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Abstract

Collision with and subduction of an oceanic plateau is a rare and transient process that usually leaves an indirect imprint only. Through a tectono-stratigraphic analysis of pre-Oligocene sequences in the San Jacinto fold belt of Northern Colombia, we show the Late Cretaceous to Eocene tectonic evolution of northwestern South America upon collision and ongoing subduction with the Caribbean plate. We linked the deposition of four forearc basin sequences to specific collision/subduction stages and related their bounding unconformities to major tectonic episodes. The Upper Cretaceous Cansona sequence was deposited in a marine forearc setting in which the Caribbean plate was being subducted beneath northwestern South America, producing contemporaneous magmatism in the present-day Lower Magdalena Valley basin. Coeval strike slip faulting by the Romeral wrench fault system accommodated right-lateral displacement due to oblique convergence. In Latest Cretaceous times, the Caribbean plateau collided with South America marking a change to more terrestrially-influenced marine environments characteristic of the upper Paleocene to lower Eocene San Cayetano sequence, also deposited in a forearc setting with an active volcanic arc. A lower to middle Eocene angular unconformity at the top of the San Cayetano sequence, the termination of the activity of the Romeral Fault system and the cessation of arc magmatism are interpreted to indicate the onset of low-angle subduction of the thick and buoyant Caribbean plateau beneath South America, which occurred between 56 and 43 Ma. Flat subduction of the plateau has continued to the present and would be the main cause of amagmatic post-Eocene deposition.

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... This implies that the Eocene sedimentary records were uplifted during the late Eocene and early Oligocene interval and subsequently eroded and sedimented during the late Oligocene (Fig. 10B, C). This erosional hiatus has been also identified in the San Jacinto Basin (Mora et al., 2017) and coincides with a middle Eocene -Oligocene exhumation peak along the CG Domain (between~50-35 Ma) and the PC Block (between 35 Ma and 28 Ma) - (Vinasco et al., 2015;León et al., 2018). This implies that the interaction between the Panamá-Chocó Block and northern South America started as early as the late Eocene (Farris et al., 2011) -(Figs. ...
... 10,11,12). A similar change in tectonic configuration has been proposed for the Tumaco Basin, south of the study area (Echeverri et al., 2015) and San Jacinto Basins, north of the studied area (Mora et al., 2017). The presence of an upper Eocene -lower Oligocene erosional hiatus along the westernmost part of the Middle Magdalena Valley Basin - (Reyes-Harker et al., 2015), the Cauca -Patía Basin (Sierra and Marín-Cerón, 2012) and southern part of the San Jacinto Basin (Rosero et al., 2014;Alfaro and Michael Holz, 2014;Mora et al., 2017) - (Fig. 3) suggests that the change from a fore-arc to an intra-arc tectonic setting did not resulted on intramontane siliciclastic deposition along the Romeral Suture, but instead in continuous erosion lasting at least 7 Ma (between 35 and 28 Ma). ...
... A similar change in tectonic configuration has been proposed for the Tumaco Basin, south of the study area (Echeverri et al., 2015) and San Jacinto Basins, north of the studied area (Mora et al., 2017). The presence of an upper Eocene -lower Oligocene erosional hiatus along the westernmost part of the Middle Magdalena Valley Basin - (Reyes-Harker et al., 2015), the Cauca -Patía Basin (Sierra and Marín-Cerón, 2012) and southern part of the San Jacinto Basin (Rosero et al., 2014;Alfaro and Michael Holz, 2014;Mora et al., 2017) - (Fig. 3) suggests that the change from a fore-arc to an intra-arc tectonic setting did not resulted on intramontane siliciclastic deposition along the Romeral Suture, but instead in continuous erosion lasting at least 7 Ma (between 35 and 28 Ma). Intra-arc/intramontane sedimentation along the Romeral Suture would have restarted during the late Oligocene with the Lower Member of the Amagá Formation (Fig. 10C). ...
Article
The late Oligocene-middle Miocene Amagá Formation is a continental siliciclastic succession deposited along several semi-isolated intramontane sedimentary basins in the northwestern the Andes. Despite the potential information that this sedimentary record may bear on the evolution of tropical intramontane siliciclastic successions along active Andean type convergent margins, little is known about its provenance. Here we document petrographic, heavy mineral and detrital zircon U-Pb ages data from the Amagá Formation, cropping out along the Santa Fe de Antioquia - San Jerónimo Sub-Basin, from which we investigate the evolution and controlling factors leading to changes in its provenance. Sandstones from the late Oligocene Lower Member of the Amagá Formation display compositional modes and U-Pb detrital zircon ages which suggest sediment sources exclusively associated to the continental South American Plate. The compositional modes and detrital zircon U-Pb ages of sandstones from the early - middle Miocene Upper Member suggest, instead, sediment sources associated to both, the South American Plate and the allochthonous Panamá-Chocó Block. In particular, the Upper Member documents the arrival of detrital zircons younger than 50 Ma (18.7, 21.0, 25.3, 31.9, 40.7, 45.1 Ma), which are not present in the South American Plate. This change in provenance parallels a change in sedimentary environments, from meandering (Lower Member) to braided (Upper Member) rivers, which have been interpreted as a major decrease in sediment accommodation space along the northern Andes. This decrease in accommodation space is associated to a regional accelerated uplift in the northern Andes resulting from the early Miocene accretion of the Panamá-Chocó Block to northern South America.
... For this purpose, the National Hydrocarbons Agency (ANH) has drilled several cores of exploratory wells in order to know and understand in detail the petroleum systems of the Colombian Caribbean, because its stratigraphic and structural complexity difficult to understand the geologic evolution of the basin (e.g., Taboada et al., 2000;Cediel et al., 2003;Pindell et al., 2005;Escalona and Mann, 2011;Cardona et al., 2012;Rosello and Cossey, 2012;Alfaro and Holz, 2014;Mora et al., 2017Mora et al., , 2018Silva-Tamayo et al., 2017;Montes et al., 2019). The stratigraphic studies involving the geological evolution of the SSJB show the difficulty for the establishment of the elements of the petroleum system given the continuous variation of facies both lateral and vertically (Duque-Caro, 1991;Guzmán et al., 2004;Guzmán, 2007;Bermúdez et al., 2009;Bermúdez, 2016;Mora et al., 2017Mora et al., , 2018Osorio-Granada et al., 2020;Manco-Garc é s et al., 2020). ...
... For this purpose, the National Hydrocarbons Agency (ANH) has drilled several cores of exploratory wells in order to know and understand in detail the petroleum systems of the Colombian Caribbean, because its stratigraphic and structural complexity difficult to understand the geologic evolution of the basin (e.g., Taboada et al., 2000;Cediel et al., 2003;Pindell et al., 2005;Escalona and Mann, 2011;Cardona et al., 2012;Rosello and Cossey, 2012;Alfaro and Holz, 2014;Mora et al., 2017Mora et al., , 2018Silva-Tamayo et al., 2017;Montes et al., 2019). The stratigraphic studies involving the geological evolution of the SSJB show the difficulty for the establishment of the elements of the petroleum system given the continuous variation of facies both lateral and vertically (Duque-Caro, 1991;Guzmán et al., 2004;Guzmán, 2007;Bermúdez et al., 2009;Bermúdez, 2016;Mora et al., 2017Mora et al., , 2018Osorio-Granada et al., 2020;Manco-Garc é s et al., 2020). ...
... The NW corner of South America is influenced by the interaction between Nazca, Caribbean and South America plates (Montes et al., 2019;Mora-Paez et al., 2019). This complex interaction has controlled the filling of the sedimentary basins from the Upper Cretaceous to the Recent (Mora et al., 2017(Mora et al., , 2018(Mora et al., , 2018Montes et al., 2019;Pardo-Trujillo et al., 2020). ...
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Basin analysis from Colombian Caribbean is particularly important given the interest in finding hydrocarbon reservoirs, but their complex geological evolution, and the frequent lateral and vertical variation of facies difficult a conclusive characterization, highlights the need for detailed sedimentological and ichnological studies. The study succession corresponds to an interval of a well core drilled in the south of the Sinú-San Jacinto Basin (Colombian Caribbean), with 1069 ft (∼326 m) thick of an Oligocene siliciclastic succession, interpreted in general terms, as deposited in a deltaic system. The integrated sedimentological/ichnological analysis allows the differentiation of dominant facies, with predominant lithologies such as conglomerates, sandstones, mudrocks, bioclastic sediments, as well as coal beds. The ichnological assemblage is low in abundance and moderately diverse, composed by Conichnus, Cylindrichnus, Dactyloidites, Macaronichnus, Ophiomorpha, Phycosiphon, Skolithos, Taenidium, Teichichnus, and Thalassinoides, as well as rhizoliths. The complexity of the sedimentary system is reflected in its evolution throughout the Oligocene. A type succession with coarsening-upward trend was identified and it is repeated through the succession studied. It presents a general trend from bioclastic sediments (bioclastic conglomerates, sandstones and mudrocks) that pass into laminated and massive mudrocks occasionally bioturbated by Phycosiphon, and interbedded by mudrocks and sandstones with lenticular bedding, and the occurrence of Teichichnus. Above, bioturbated muddy sandstones with Ophiomorpha, Taenidium, Thalassinoides, and rarely Teichichnus, muddy sandstones with planar cross-lamination, and laminated bedding sandstones with Dactyloidites, Ophiomorpha, Skolithos, and Thalassinoides are registered. Transition to carbonaceous mudrocks with Teichichnus, coal medium beds, and fine-to coarse-grained sandstones sometimes with Macaronichnus and/or Ophiomorpha is observed. Towards the top, are observed mudrocks with rhizoliths. This succession is interrupted by massive and laminated sandstones with low bioturbation index generated by the ichnological assemblage and/or by the exclusive occurrence of Ophiomorpha and/or Taenidium. Massive sandstones with erosive bases, asymmetrical ripples, and high content of organic debris are occasionally recorded. This succession reflects a progradational trend similar to those of fluvial-dominated deltaic sequences. Detailed analysis revealed that even the fluvial processes were dominant in the deltaic system; however, local tidal and wave influence is recorded. Moreover, integration of sedimentological and ichnological information allows characterizing the evolution of the different sub-environments of the deltaic system, as prodelta bay, distal delta front, proximal delta front, distributary channels, mouth bars, and lower delta plain, and this is essential for areas of economic interest.
... Se ha documentado la convergencia oblicua y subducción de la placa del Caribe bajo la placa Sudamericana desde el Cretácico Superior hasta el Eoceno Inferior en el norte de Colombia (Mora et al., 2017a(Mora et al., , 2017b. Dicha subducción generó un arco magmático en la actual Cordillera Central y en la cuenca del Valle Inferior del Magdalena. ...
... Esta unidad ha recibido varios otros nombres litoestratigráficos (e.g. Luruaco, Arroyo Seco) y ha sido interpretada por Mora et al. (2017b) como una secuencia estratigráfica de segundo orden (sensu Vail et al., 1977) que corresponde a un ciclo de alto rango/baja frecuencia (sensu Catuneanu et al., 2009). Con base en estudios de afloramiento (Duque-Caro, 1979, 1991Guzmán et al., 2004;Salazar-Ortiz et al., 2020b), en recientes interpretaciones de sísmica 2D y en descripciones de núcleos de algunos pozos estratigráficos perforados por la Agencia Nacional de Hidrocarburos (ANH), se ha propuesto que la secuencia de la Formación San Cayetano se encuentra limitada por discordancias regionales angulares, una a la base sobre sedimentos cretácicos de la Formación Cansona y una al tope bajo sedimentos del Grupo Chengue del Eoceno Medio. ...
... Con base en estudios de afloramiento (Duque-Caro, 1979, 1991Guzmán et al., 2004;Salazar-Ortiz et al., 2020b), en recientes interpretaciones de sísmica 2D y en descripciones de núcleos de algunos pozos estratigráficos perforados por la Agencia Nacional de Hidrocarburos (ANH), se ha propuesto que la secuencia de la Formación San Cayetano se encuentra limitada por discordancias regionales angulares, una a la base sobre sedimentos cretácicos de la Formación Cansona y una al tope bajo sedimentos del Grupo Chengue del Eoceno Medio. También se ha propuesto que la Formación San Cayetano se depositó en ambientes que varían entre turbiditas arenosas en el sur, "fan deltas" en el centro y turbiditas principalmente lodosas en el norte del Cinturón de San Jacinto (Mora et al., 2017b). Las arenitas de la Formación San Cayetano se clasifican principalmente como litoarenitas, sublitoarenitas y arenitas feldespáticas con clastos de diversos tipos: ígneo plutónico y volcánico, metamórfico y sedimentario, incluyendo abundantes clastos de chert negro con foraminíferos planctónicos cuya proveniencia serían las capas de cherts Cretácicos de la Formación Cansona (Mora et al., 2017b). ...
Article
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The San Jacinto Fold Belt comprises a heterolithic succession, particularly in the Lower Paleogene, which might hamper the presence of diagnostic fossils. This case is notorious in the San Cayetano Formation, which strata have been interpreted as deposited in turbiditic setting and presents a late Paleocene-Early Eocene age using foraminiferal assemblages. However, the presence of foraminifers in the San Cayetano Formation is scattered, mostly constituted by benthic agglutinated assemblages, and the input of new data (sedimentology, macrofossils) have increased the discussion about the age and depositional context of that unit. Considering these issues, a detailed taxonomic study of the foraminiferal assemblages that define the Lower Paleogene in the San Jacinto Fold Belt was elaborated, using material of several sections of the San Cayetano Formation. Despite the agglutinated foraminifers present low diversity values, these have several abundance and preservation degrees, comprising tubular and multiserial agglutinated forms. Though some of the taxa have been referred in the San Cayetano formation, some of the identified species such as Aschemocella subnodosiformis, Bathysiphon eocanicus, Budhashevaella trinitatensis, Nothia lattissima or Reticulophragmoides jarvisi might refine the age proposal of late Paleocene-early Eocene. Furthermore, the foraminifers can be interpreted as flysch-type assemblages, or also associated with highly unstable substrates, aspects previously reported for this unit. In view of the most recent studies on the San Cayetano Formation, our contribution reinforces the importance of integrating paleontological and sedimentological data in incoming projects. This, in order of segregating the possible turbiditic settings of this unit from those proposed like more proximal.
... The RFS, which is also considered to continue to the north to form the western boundary of the LMV, appears to be separating the oceanic to transitional basement under the belt from the felsic continental basement of the South American crust, which floors the LMV in the east (Duque-Caro, 1979, 1984Flinch, 2003;Mora et al., 2017a). In the SJFB, located west of the RFS, there are Upper Cretaceous to Eocene sedimentary units that are not preserved in the LMV to the east (Duque-Caro, 1979, 1984Mora et al., 2017b). By contrast, Oligocene to Recent units that have been mostly eroded in the SJFB, are well preserved in the LMV and they are the focus of the tectono-stratigraphic analysis performed in this study. ...
... SB: Sequence boundary; mfs: maximum flooding surface. Modified from Mora et al. (2017b). ...
... The SJFB records the existence of a Late Cretaceous to Early Eocene forearc basin, which was inverted in early to middle Eocene times and was then covered and sealed by middle Eocene to lower Oligocene units ( Fig. 2 and Mora et al., 2017b). These authors divided the sedimentary succession in the SJFB into four tectono-stratigraphic sequences, bounded by regional unconformities, which are related to major tectonic events. ...
Article
Mechanisms of forearc basin evolution remain not very well understood, mostly because of insufficient resolution of their temporal evolution and potential drivers. The convergent margin of northwest Colombia where the San Jacinto and Lower Magdalena Valley forearc basins are located, offers a unique opportunity to study such mechanisms. The formation of the Lower Magdalena amagmatic, forearc basin occurred in a stable setting from the Oligocene to the present, characterized by the slow and nearly orthogonal, low-angle subduction of the Caribbean plateau. We use an exceptional regional database to reconstruct the subsidence, extension, sedimentation and paleo-geographic history of the Lower Magdalena forearc basin. We propose possible mechanisms controlling its evolution, in the absence of major changes in plate kinematics and in a low-angle subduction setting. Following the collapse of a pre-Oligocene magmatic arc, late Oligocene to early Miocene fault-controlled subsidence allowed initial basin fill at relatively low sedimentation rates. After the connection of the Lower and Middle Magdalena valleys, the proto-Magdalena river in the north and the proto-Cauca river in the south both started delivering high amounts of sediments in middle Miocene times. Fault controlled subsidence was gradually replaced by subsidence due to increased sedimentary load. Increase in sediment flux would have also caused the formation of an accretionary prism, weakened the plate interface through lubrication with fluid-rich sediment and initiated underplating, with the development of forearc highs in the San Jacinto area. Inherited basement structures allowed the tectonic segmentation of the basin with the formation its two depocenters (Plato and San Jorge). Our results highlight the fundamental role of sediment flux, of the basement structure and of flat subduction on the evolution of forearc basins such as the Lower Magdalena.
... According to the aforementioned and after providing a summary of the regional geological context (Chapter 2), I continue with a study of the basement underneath the Lower Magdalena Valley basin (Chapter 3, Mora et al., 2017a) , based on the analysis of potential methods, reflection seismic interpretation, well data and sampling, basement U-Pb zircon geochronology and Hf-isotope geochemistry, in order to characterize the basement in terms of structure, age and possible formation mechanisms This study is tackling the first question about the basement underneath the LMV and SJFB, though it has been focused mainly on the LMV, due to the scarcity of basement data in the SJFB. In Chapter 4, I present the results of a tectono-stratigraphic study of the pre-Oligocene (Upper Cretaceous to Eocene) sedimentary sequences in the San Jacinto fold belt, in which I also established a link between the deposition of such sequences and the Cretaceous to Eocene plate kinematics and convergence history between the Caribbean oceanic plate and the South American continental plate (Mora et al., 2017b). This chapter is therefore providing answers to questions 2 and 4, about the Late Cretaceous to Eocene paleo-tectonic evolution of NW Colombia. ...
... This chapter is a reformatted version of a Tectonics paper (Mora et al., 2017b). Supplementary text and figures have been placed in Appendix B. ...
... Citation: Mora, J.A., Oncken, O., Le Breton, E., Ibáñez-Mejía, M., Faccena, C., Veloza, G., Vélez, V., De Freitas, M., Mesa, A., 2017b Abstract Collision with and subduction of an oceanic plateau is a rare and transient process that usually leaves an indirect imprint only. Through a tectono-stratigraphic analysis of pre-Oligocene sequences in the San Jacinto fold belt of Northern Colombia, we show the Late Cretaceous to Eocene tectonic evolution of northwestern South America upon collision and ongoing subduction with the Caribbean plate. ...
Thesis
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In this thesis I used a regional geological and geophysical dataset to reconstruct the Late Cretaceous to Recent evolution of the Lower Magdalena Valley basin and San Jacinto fold belt of NW Colombia. My detailed interpretations of reflection seismic data and new geochronology analyses reveal that the Lower Magdalena basement is the northward continuation of the basement terranes of the northern Central Cordillera, consisting of Permo-Triassic metasediments, which were intruded by Late Cretaceous granitoids. Structural analyses suggest that the NE-SW trend of basement faults in the northeastern Lower Magdalena is inherited from a Jurassic rifting event, while the ESE-WNW trend in the western part is inherited from a Late Cretaceous to Eocene strike-slip and extension episode. The Upper Cretaceous to lower Eocene sediments preserved in the present day San Jacinto fold belt were deposited in a forearc marine basin formed by the oblique convergence between the Caribbean and the South American plates. A lower to middle Eocene angular unconformity at the top of the San Cayetano sequence, the termination of the activity of the Romeral Fault system and the cessation of arc magmatism are interpreted to indicate the onset of low-angle subduction of the Caribbean plateau beneath South America, which occurred between 56 and 43 Ma. Flat subduction of the plateau has continued to the present and would be the main cause of amagmatic post-Eocene deposition and formation of the Lower Magdalena Valley basin. After the collapse of a pre-Oligocene magmatic arc, late Oligocene to early Miocene fault-controlled subsidence allowed initial infill of the Lower Magdalena with relatively low sedimentation rates. Extensional reactivation of inherited, pre-Oligocene basement faults was crucial for the tectonic segmentation of the basin with the formation of its two depocenters (Plato and San Jorge). Oligocene to early Miocene uplift of Andean terranes made possible the connection of the Lower and Middle Magdalena valleys, and the formation of the most important Colombian drainage system (Magdalena River system). This drainage system started delivering high volumes of sediment in middle Miocene times, as fault-controlled subsidence was gradually replaced by sagging due to increased sedimentary load. Such an increase in sedimentation delivering great sediment volumes to the trench, caused the formation of forearc highs in San Jacinto and of an accretionary prism farther to the west. These results highlight the fundamental role of changes in plate kinematics, of the inherited basement structure and of sediment flux on the evolution of forearc basins such as Lower Magdalena and San Jacinto. Based on my interpretations and results about the evolution of the Lower Magdalena and San Jacinto, a three-dimensional model of the Lower Magdalena Valley basin was built from seismic and well data, and used to reconstruct the thermal and maturation history of the basin. I reconstructed the stratal architecture of the basin, implemented within the model episodes of uplift and erosion, and built a geothermal gradient map, which was used to construct heat flow maps for 3-D modeling. Model results indicate that the onset of hydrocarbon generation occurred at ~15 Ma (middle Miocene) for upper Oligocene to lower Miocene hydrocarbon source rocks in the northern part of the basin (Plato depocenter), while younger, lower Miocene sources started generating at ~ 9 Ma (middle-late Miocene). Maturation was influenced by sedimentation at very high rates of thick, deep marine to deltaic, Oligocene to upper Miocene sequences. Late Miocene generation was interrupted by shortening and uplift events at Pliocene (4-3 Ma) and Pleistocene times, though it appears to be ongoing in main depocenters. Low to fair source rock quality appears to be compensated by high thicknesses of the Oligocene to lower Miocene sources, which would still be generating below 3,350 m (11,000 ft) in the main pod of active source rock in the northern Lower Magdalena (Plato depocenter). By contrast, the effects of shortening pulses and low heat flow would have inhibited maturation of Oligocene to lower Miocene source rocks in the San Jorge graben of the southern Lower Magdalena, suggesting the need of additional hydrocarbon sources to explain the dry gas occurrences in that part of the basin. Proposed additional sources are pre-Oligocene units preserved in the western San Jorge depocenter, and biogenic generation. The results of this thesis provide new insights into the controls of plate tectonics and basin evolution on petroleum systems.
... Previous studies in the Caribbean province, located in the North Andean Block at northwestern South America, have been mainly focused on Late Cretaceous to Early Oligocene tectonostratigraphic sequences of the San Jacinto Fold Belt (SJFB), linking the Caribbean-South America plate boundary evolution to the Caribbean Plateau collision (e.g. Cardona et al., 2012;Mora et al., 2017b;Osorio-Granada et al., 2020) (Figure 1). ...
... The Caribbean-South American convergent margin has shown different pulses of deformation since Late Cretaceous, period in which is suggested a subduction erosion after an accretionary event (Mora et al., 2017b). An Oligocene-Early Miocene stratigraphic section in the SJFB was studied, which is part of the Ciénaga de Oro Formation (COF) and represents the first episode of sedimentation above the Oligocene unconformity (Arminio et al., 2011). ...
... This study strive to contribute to enhance the understanding of this complex issue by using a multi-tool approach throughout: 1) clastscounting in sandstones and conglomerates with mesh, 2) heavy minerals assemblages, 3) paleocurrents, and 4) U-Pb detrital zircon ages. (Mora et al., 2017b), Late Paleocene -Late Eocene (Cardona et al., 2012), Early Eocene -Oligocene (Osorio-Granada et al., 2020) sediments and the stratigraphic section are also included. ...
Article
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How to cite: Manco-Garcés, A.; Marín-Cerón, M.I.; Sánchez-Plazas, C.J.; Escobar-Arenas, L.C.; Beltrán-Triviño, A.; von Quadt, A. (2020). Provenance of the Ciénaga de Oro Formation: unveiling the tectonic evolution of the Colombian Caribbean margin during the Oligocene-Early Miocene. Boletín de Geología, 42(3), 205-226. https://doi.org/10.18273/revbol.v42n3-2020009 Supplementary material: This article has supplementary material. Abstract A stratigraphic section in the San Jacinto fold and thrust belt located at northwestern Colombia was studied. This section displays part of the Oligocene-Early Miocene Ciénaga de Oro Formation (COF). This work analyses the sediments provenance using a multi-tool approach which include: (I) conglomerate and sandstone counting clast with mesh, (II) heavy minerals assemblages, (III) paleocurrents and (IV) U/Pb detrital zircon ages. The sedimentary sequence was deposited in deltaic to transitional environment deposition, with reduction in the waves and tidal effect, and increase in the dominance of transitional river processes upward the section. Two main source areas have been identified from a dissected arc province: a main granitic to pegmatitic and a secondary basic igneous source rocks, located to the east and southwest of the current position. Detrital zircon U-Pb geochronology analysis display four age populations: (I) Devonian-Permian, (II) Permian-Triassic, (III) Jurassic and (IV) Cretaceous, with maximum deposition ages of 75.2±0.9 Ma in the lower part of the section, 68.9±0.6 Ma in the middle and 74.5±0.7 Ma for the upper part. It is proposed that COF was sediment-supplied by a south-to-north fluvial system, which drained exposed basement blocks and their late Cretaceous to Paleogene sedimentary cover during the Oligocene. This fluvial system carried sediments from late Cretaceous plutons like the Antioqueño Batholith and mafic/ ultramafic rocks, which make up the basement of the Western and Central Cordilleras.
... The Meso-Cenozoic tectonic evolution of the Northern Andes is characterized by the interaction of the South American continental margin with a series of allochthonous terranes of oceanic affinity, which were accreted diachronously along different segments of the continental margin and subsequently fragmented and dispersed along transcurrent fault systems during the Cenozoic (Toussaint, 1996;Ramos and Aleman, 2000;Cediel et al., 2003;Villagómez, 2010;Bayona et al., 2012;Spikings et al., 2015;Mora et al., 2017). ...
... The tectonic configuration of the western margin of the Northern Andes is limited by a suture, known regionally as the Romeral Fault System (RFS). The RFS demarcates the collision of oceanic units to the west and continental units to the east, and is defined by the presence of dispersed ultramafic rocks (Cediel et al., 2003;Villagómez, 2010;Spikings et al., 2015;Mora et al., 2017). The origin of these ultramafic rocks may be associated with different oceanic elements formed in environments of MOR (e.g. ...
... It is made up of three anticlinorium structures: San Jerónimo, San Jacinto, and Luruaco (Duque-Caro, 1980;González and Londoño, 2001;Geotec Ltda, 2003;Guzmán et al., 2004). They comprise marine sediments with terrigenous influence which were deposited in a fore-arc environment and later accreted to the northern margin of Colombia during the Eocene (Villagómez, 2010; Mora et al., 2017): the Upper Cretaceous Cansona Formation, the Upper Paleocene to Lower Eocene San Cayetano Formation, and the Middle to Upper Eocene Chengue and San Jacinto Formations. Based on U/Pb geochronology and Hf-isotopes on detrital zircons, Mora et al. (2017) suggested that the San Cayetano and Chengue/ San Jacinto sequences represent Late Cretaceous oceanic and continental magmatic arcs, respectively. ...
Article
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Platinum-group elements (PGE) are included among the so-called critical metals, and are essential metals for the technological industry. However, there are very few deposits in the world from which these metals can be extracted. The present work investigates three Ni-laterite profiles (hydrous Mg silicate type) formed over the ultramafic rocks of Cerro Matoso and Planeta Rica in Colombia. The main goal is to determine their PGE concentration and distribution, as well as to identify the carrier phases of these noble metals. The highest PGE contents in Cerro Matoso and Planeta Rica are concentrated in the limonite horizon (141–272 ppb), showing a strong decrease towards the saprolite and the underlying serpentinized peridotite (parent rock; < 50 ppb). The highest concentrations correspond to Pt>Ru>Pd and the lowest to Rh<Os<Ir. Such distribution indicates that PGE are mobilized in different proportions by the laterization processes. The high affinity between PGE and Fe favors the formation of PGE-Fe mineral alloys such as the Pt-IrFe-Ni minerals hosted by Fe-oxyhydroxide found in the limonite–saprolite transition zone in Planeta Rica. In addition, in the same zone, nanoparticles of Pt (< 1 µm) were found within framboidal pyrite. Both types of platinum group minerals (PGM) are secondary in origin. In the case of Pt-IrFe-Ni alloys, this interpretation is supported by their morphology and chemical composition, which is comparable with PGE-Fe-Ni alloys found in laterites of Dominican Republic. In the case of Pt nanoparticle, textural relations suggest the neoformation of PGM adhered to the porous edges of altered pyrite. Cerro Matoso and Planeta Rica should be considered as unconventional PGE deposits, if adequate recovery processes can be applied for their recovery as by-products during Ni (+Co) production.
... The basement underneath the LMV was characterized, based on the integration of a regional subsurface database, which included geochronologic analyses of borehole samples in combination with outcrop data from the literature (Figure 3; Mora et al., 2017a). Then, the tectono-stratigraphy of Upper Cretaceous to Eocene sequences in the forearc basin that today corresponds to the SJFB was studied, linking them with the plate tectonic kinematics (Mora et al., 2017b). Finally, the Oligocene to recent tectono-stratigraphic sequences in the LMV were studied, and the subsidence, extension, sedimentation, and paleo-geographic history of the basin was reconstructed, proposing possible mechanisms controlling its evolution (Mora et al., 2018). ...
... Though there has been some debate about the occurrence of flat-subduction of the Caribbean Plate under South America, beneath the LMV and SJFB (e.g., Rosello & Cossey, 2012), GPS data have shown (e.g., Müller et al., 1999;Trenkamp et al., 2002;Boschman et al., 2014;Matthews et al., 2016) that NW South America and the Caribbean are converging in a nearly orthogonal fashion (Symithe et al., 2015). Furthermore, seismicity data indicates the existence of a Benioff zone in the eastern LMV (Bernal-Olaya et al., 2015a;Syracuse et al., 2016;Mora et al., 2017aMora et al., , 2017b, while geophysical studies including tomography data (Mantilla-Pimiento, 2007;Mantilla-Pimiento et al., 2009;Bernal-Olaya et al., 2015a), have provided new and more robust evidence supporting a flat-subduction geometry. Hence, there is agreement between the results and interpretations of this study and previous proposals (e.g., Mantilla-Pimiento et al., 2009), which consider the LMV as a forearc basin within a convergent margin where flat-slab subduction is operational (Bernal-Olaya et al., 2015a, 2015b, 2015c. ...
... The RFS, which is also considered to continue from the south to form the western boundary of the LMV, separates the oceanic to transitional basement under the belt from the felsic continental basement of the South American crust, which floors the LMV in the east (Duque-Caro, 1979, 1984Flinch, 2003;Mora et al., 2017a). In the SJFB, located west of the RFS, there are Upper Cretaceous to Eocene sedimentary units that are not preserved in the LMV to the east (Duque-Caro, 1979, 1984Mora et al., 2017b). By contrast, Oligocene to recent units have been mostly eroded in the SJFB and are well preserved in the LMV (Figures 4 and 5). ...
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Using a regional geological and geophysical dataset, we reconstructed the stratigraphic evolution of the Lower Magdalena Valley basin and San Jacinto fold belt of northwestern Colombia. Detailed interpretations of reflection seismic data and new geochronology analyses reveal that the basement of the Lower Magdalena basin is the northward continuation of the basement terranes of the northern Central Cordillera and consists of Permo-Triassic metasedimentary rocks intruded by Late Cretaceous granitoids. Structural analyses suggest that the NE-SW strike of faults in basement rocks underlying the northeastern Lower Magdalena is inherited from a Jurassic rifting event, while the ESE-WNW –striking faults in the western part originated from a Late Cretaceous to Eocene strike-slip and extensional episode. The Upper Cretaceous to lower Eocene sedimentary rocks preserved in the present-day San Jacinto fold belt were deposited in a submarine, forearc basin formed during the coeval oblique convergence between the Caribbean and South American plates. A lower to middle Eocene angular unconformity at the top of the upper Paleocene to lower Eocene San Cayetano sequence, the termination of the activity of the Romeral Fault system, and the cessation of arc magmatism are all interpreted to indicate the onset of low-angle orthogonal subduction of the Caribbean plateau beneath South America between 56 and 43 Ma. Flat subduction of the plateau has continued to the present and would be the main cause of amagmatic post-Eocene deposition and formation of the Lower Magdalena Valley forearc basin. Extensional reactivation of inherited, pre-Oligocene basement faults was crucial for the tectonic segmentation of the basin and the formation of its two depocenters (Plato and San Jorge). Late Oligocene to early Miocene fault-controlled subsidence allowed initial infill of the Lower Magdalena, while uplift of Andean terranes made possible the connection of the Lower and Middle Magdalena valleys, and the formation of the largest Colombian drainage system (Magdalena River system). This drainage system started delivering enormous amounts of sediments in middle Miocene times, as fault-controlled subsidence was gradually replaced by sedimentary loading. Such dramatic increase in sedimentation and the huge volume of sediment being delivered to the trench caused the formation of forearc highs in San Jacinto and of an accretionary prism farther to the west. Our results highlight the fundamental role of plate kinematics, inherited basement structure and sediment flux on the evolution of forearc basins such as the Lower Magdalena and San Jacinto.
... The southernmost edge of the Caribbean (CAR) plate subducts obliquely at a low angle beneath northwestern South America (NWSA) due to a buoyant large igneous province impinging on a trench that lies offshore northwestern Colombia ( Figure 1) (Burke, 1988;Kellogg & Bonini, 1982;Pennington, 1981). Like other flat slab subduction zones, the overriding South American plate has lacked magmatism for at least 45 m.y., has mountains up to ∼500 km from the trench and is seismically active over that same length (Figures 3 and S1) (e.g., Cardona, Valencia, Bayona, et al., 2011;Mora et al., 2017;Taboada et al., 2000). However, the subducting CAR has not been previously well imaged due to limited instrumentation, leaving open questions regarding how the flat slab contributes to the Laramide-style uplifts seen in NWSA (e.g., Audemard & Audemard, 2002;Monod et al., 2010). ...
... Where this transition occurs is not resolved. It has been proposed to be along the Oca-Ancón fault near Lake Maracaibo (Masy et al., 2015) and south of the Oca-Ancón fault near the Santa Marta Massif (Mora et al., 2017). Farther south the subduction of CAR ends. ...
... Along the Southern Caribbean Deformation Belt, where no physiographic trench is visible due to sedimentation into the Colombia and Venezuela basins, the CAR under-thrusts the northern edge of NWSA and subducts beneath the northwest margin of NWSA ( Figure 1) (Miller et al., 2009;van der Hilst & Mann, 1994). The CAR began subducting beneath NWSA between 70 and 55 Ma, coinciding with magmatism along the margin (Cardona, Valencia, Bayona, et al., 2011;Mora et al., 2017). By 45-55 Ma magmatism abruptly ceased, likely due to the onset of low-angle subduction of the Caribbean Large Igneous Province (CLIP) (Montes et al., 2019;Mora et al., 2017;Taboada et al., 2000). ...
... This contributes to the controversy about the existence/absence of an ongoing subduction process along this boundary (Rossello and Cossey., 2012). Nevertheless, recent studies support the existence of active subduction (Vargas and Mann., 2013;Lara et al., 2013;Vargas et al., 2015;Bernal-Olaya et al., 2015;Syracuse et al., 2016;Mora et al., 2017;Pérez et al., 2018;Vargas, 2020). ...
... For example, the age of the subducting oceanic lithosphere is 10-50 Ma for the Nazca plate and more than 90 Ma for the Caribbean plate. The subduction rate in South American fixed reference frame and dip angle of the subducting slab is ~54 mm/yr and ~28 • (Lallemand et al., 2005) for the Nazca plate, and ~17 mm/yr and ~8 • (Mora et al., 2017) for the Caribbean plate, respectively. Probably related with these differences, there is no active volcanic arc along the Caribbean while the Nazca subduction is characterized by active volcanism. ...
... It is essential to assume an appropriate configuration of the subducting Caribbean plate in order to evaluate the interplate coupling. In this study, we use a geometry by Mora et al. (2017) estimated by integrating seismic reflection data for the shallow part, seismicity for the intermediate part and seismic tomography for the deeper part of the slab. We digitize the published depth contours and compute a spatial interpolation using the "surface" command of the Generic Mapping Tools (GMT) (Wessel et al., 2013) to obtain a continuous surface configuration (See Fig. 5). ...
Article
Northwestern Colombia is located at a convergent plate boundary between the Caribbean plate and the North Andean Block; however, no megathrust earthquakes have been reported during last 500 years. In order to evaluate seismic potential in this area, we analyze GPS data during 2007–2018 from GeoRED – the nationwide GPS array in Colombia – to obtain interseismic 3-dimensional velocities. GPS velocity data indicate the northern part of the North Andean Block is differentiated as another block and we name it Macondo Block. The velocity data are then inverted to estimate interplate coupling on the subducting Caribbean plate interface. The result shows an isolated, fully locked patch south of the city of Cartagena extending from 9.0 to 20 km in depth on the subduction interface with an area of ∼11,000 km². The estimated locked patch implies a potential of M-8 class earthquake with an average recurrence time of ∼600 years, which is consistent with the absence of such an event in the available historical record. As another possibility, the observed surface deformation may be accommodated inelastically. A comparison of geological and geodetic strain rates in the convergence direction shows that the geological one is smaller by one or two orders of magnitude and does not support such an interpretation though the estimate itself still has a large uncertainty. For improving the evaluation of earthquake/tsunami potential, it is essential to conduct a careful geological investigation to identify recent evidence of crustal shortening or paleotsunami along northwestern Colombia.
... An important tectonic event that influenced the evolution of the Cenozoic sedimentary basins in northern South America is the middle Eocene initial interaction between Central America and South America (Farris et al., 2011;Montes et al., 2012). This event, which caused the opening of several middle Eocene marginal basins, was followed by the onset of low-angle flat subduction of the Caribbean Plate under the South American Plate during the late Eocene -Oligocene interval (Mora et al., 2017). This tectonic reorganization resulted in fore-arc extension and enhanced subsidence, and siliciclastic sedimentation along several of the middle Eocene incipient marginal basins in northern South America. ...
... This tectonic reorganization resulted in fore-arc extension and enhanced subsidence, and siliciclastic sedimentation along several of the middle Eocene incipient marginal basins in northern South America. In the San Jacinto and Alta Guajira Basins, these conditions favored the coeval occurrence of late Eocene coarse-grained clastic and shallow marine carbonate sedimentation (Mora et al., 2017). The increase in sediment and nutrient supply from the emerged orogens into these basins, amplified by the Eocene hothouse conditions (Zachos et al., 2001(Zachos et al., , 2008, could be a mechanism to explain the predominance of heterozoan biotic associations over photozoan biotic associations as the main carbonate factory along the studied Colombian Cenozoic basins (i.e., Arroyo de Piedra Formation of the San Jacinto Basin and Macarao Formation of the Alta Guajira Basin; Figure 19). ...
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In this chapter, we report existing and new lithostratigraphic information and Sr-isotope chemostratigraphic ages of several Cenozoic marine carbonate successions deposited within numerous Colombian basins. This information is used to link main changes in the shallow marine carbonate factory to regional environ-mental/tectonic events in the tropical SE Circum-Caribbean. Our results and the available literature show that during the Eocene-early Oligocene transition, car-bonate successions developed along the Alta
... Although there is no seismic activity at the trench, the hypocenters exist to the southeast and a Benioff zone can be traced to a depth of 175 km. This confirms, as reported in previous papers (Bernal-Olaya et al., 2015;Cornthwaite et al., 2021;Mora et al., 2017;M. Sun et al., 2022;van Benthem et al., 2013), the subduction of the Caribbean plate beneath northern South America and implies that part of the plate has been consumed at this active margin. ...
... We instead suggest that the ocean crust of the Venezuela basin formed in the Pacific during the Jurassic-Cretaceous as suggested by Mauffret and Leroy (1997), and also proposed based on an analysis of marine magnetic data ( ( Figure 4b) provide evidence of the ongoing eastward movement of the Caribbean plate, and the southern boundary of the block moving to the east. Also, a slab tear or STEP fault (subduction transform edge propagator, Govers & Wortel, 2005) as indicated by Mora et al. (2017) would be present where the SSEP dextral strike-slip fault ( Figure 8) and the convergent boundary meet, indicating the SW corner of the Caribbean plate. Hayes et al. (2018) investigated the geometry of subducted slabs on a global basis and identified the seismicity of the Antilles and Central American subduction zones as extending to a depth of 200 km, whereas seismicity reaches 660 km beneath much of South America, the SW Pacific, and Japan. ...
... There, only the San Diego maar (Borrero et al., 2017), the El Escondido tuff cone (Monsalve et al., 2019;Sánchez-Torres et al., 2019), and the Pela Huevos dome (Sánchez-Torres et al., 2019) have been clearly recognized as volcanoes and therefore previously studied. This work characterizes four more monogenetic volcanic edifices (Norcasia, Piamonte, Morrón, and Guadalupe) as part of the Samaná Monogenetic Volcanic Field (SMVF), highlights the potentially active volcanism in an area previously defined as non-volcanogenic (Vargas & Mann, 2013;Syracuse et al., 2016;Mora et al., 2017;Wagner et al., 2017), and sheds light into the magmatic evolution of the scarcely studied evolved monogenetic volcanism in subduction zones around the globe (Murcia & Németh, 2020). ...
... This weakness crosses underneath the SMVF ( Figure 1A) and is known as the Caldas Tear (Vargas & Mann, 2013). The prolongation of this tear to the surface has been defined as the limit of the volcanism given by the boundary marked between a "normal" subduction (volcanogenic) to the south and a "flat" subduction (non-volcanogenic) to the north (Vargas & Mann, 2013;Syracuse et al., 2016;Mora et al., 2017;Wagner et al., 2017). However, Londoño et al. (2020), based on the recently reported volcanism north of the Caldas Tear (Borrero et al., 2017;Monsalve et al., 2019;Murcia et al., 2019;Sánchez-Torres et al., 2019), proposed to move this volcanic limit from 5 to 6°N. ...
Article
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The northernmost volcanism in South America (5–6°N) is defined by the presence of several monogenetic volcanic edifices in Colombia, which have been grouped within the Samaná monogenetic volcanic field. Few volcanoes have been studied so far, but they are recognized as a cluster of volcanoes of intermediate-to-acid composition, formed by both explosive and effusive eruptions. This study aims to 1) characterize four more monogenetic volcanic edifices as part of the Samaná field, 2) highlight the potentially active volcanism in an area previously defined as non-volcanogenic, and 3) give insights into the magmatic evolution of the scarcely studied evolved monogenetic volcanism linked to subduction zones worldwide. To achieve these aims, this study uses petrography, mineral chemistry, whole-rock geochemistry, geochronological analyses, and geothermobarometric calculations. The analyses indicate that the field is formed by at least seven volcanoes with similar composition and that it is long-lived and potentially active. Mineralogically, the erupted products host plagioclase (An26–74) and amphibole (magnesio-hastingsite, tschermakite, and occasionally mangesio-hornblende) as the most abundant phases, although orthopyroxene (enstatite; Wo2–3, En70–76, Fs21–28) and clinopyroxene (diopside and augite; Wo44–45, En41–42, Fs13–15, and Wo42–44, En46–47, Fs10–11) also appear. Less abundant phases such as olivine (Fo81–88), biotite (magnesiobiotite), quartz, and Fe–Ti oxides (Usp4–89 Mag96–11, and Ilm61–92 Hem39–8) were also recognized. Chemically, the volcanoes are of andesitic-to-dacitic composition with calc-alkaline affinity and show similar behavior of LILE, HFSE, and REE, which is typical for magmatism in subduction environments. Ages yield a range between 1.32 ± 0.06 Ma (K/Ar) and 16,919 ± 220 years (14C). The results also indicate that the volcanoes share a common magmatic source that fed the individual eruptions and that the magma differentiation is mainly controlled by processes of fractional crystallization, although evidence of magma recharge processes or magma mixing and assimilation as a minor process are also recognized. Geothermobarometric calculations suggest that the different mineral phases are crystallized between 1,194 and 687 °C and a pressure between 0.88 and 0.19 GPa. This indicates that the aforementioned processes occurred not only at the main magmatic reservoir (∼33–21 km depth) but also at different stagnation zones at shallower levels of the crust (∼7–5 km). Taking this into account, it is shown that the magma evolution of this monogenetic field is more complex than individual batches of magma reaching the surface uninterrupted, as is normally described for monogenetic volcanic fields of more mafic compositions in other tectonic settings.
... There, we find the conjunction of three plates, with the South American plate converging with both the Caribbean and Nazca plates. Matters are further complicated by the subduction of the buoyant, Cretaceous Caribbean Large Igneous Province (∼ 1.8 × 10 6 km 2 ) (Burke, 1988;Mora et al., 2017;, and the northward migration of the Nazca plate and Nazca-Caribbean-South America triple junction in the past ∼70 Ma (Boschman et al., 2014;Kellogg et al., 2019;Montes et al., 2019). This complex tectonic setting has spawned many conflicting hypotheses for how convergence between the different plates is * Corresponding author. ...
... The Maracaibo segment must be Caribbean. On the other hand, a common Caribbean origin for all three segments can also be ruled out because the Cartago segment is clearly related to active volcanism that can only be a product of Nazca subduction(Taboada et al., 2000;Wagner et al., 2017;Mora et al., 2017;Kellogg et al., 2019). The Cartago segment must belong to Nazca. ...
Article
Both the Caribbean and Nazca plates subduct beneath northwestern South America. The configuration of the two subducted slabs and the nature of any interaction between them has long been a matter of debate. Based on the location of intermediate-depth seismicity and active and extinct volcanism, as well as on seismic imaging, several different tectonic scenarios have been proposed. In this paper, we use teleseismic data recorded by the Colombian National Network and the temporary CARMA array in Venezuela and Colombia to produce a finite-frequency tomography model for the region. Our results show several distinct subduction segments. Through synthetic tests, we show that our results require a zone of overlap between Nazca and Caribbean subduction north of the “Caldas Tear” as has been proposed by previous studies. Additionally, we find that the Bucaramanga Nest occurs within the Caribbean Plate and coincides with bending of the slab in two planes, where both the strike and the dip of the slab change. We infer that elevated stresses are an important factor in producing the very high rates of seismicity in the nest.
... However, the origin and tectonic setting where these magmatic units were formed remains poorly understood and isotopic and geochemical studies must be performed. The peak at 332 Ma can be related to the San Jorge depocentre basement dates ( Figure 6; Mora et al. 2017b). These peaks have been interpreted to reflect pulses of magmatism followed by a magmatic event towards the end of the Palaeozoic, due to the subduction of oceanic crust beneath the continent, during the last stages of the amalgamation of Pangea (Alleghanian orogeny, Restrepo-Pace 1992;Vinasco et al. 2006;Mora et al. 2017b). ...
... The peak at 332 Ma can be related to the San Jorge depocentre basement dates ( Figure 6; Mora et al. 2017b). These peaks have been interpreted to reflect pulses of magmatism followed by a magmatic event towards the end of the Palaeozoic, due to the subduction of oceanic crust beneath the continent, during the last stages of the amalgamation of Pangea (Alleghanian orogeny, Restrepo-Pace 1992;Vinasco et al. 2006;Mora et al. 2017b). The corresponding detrital zircon peaks are similarly subdued, and widespread mainly throughout the Caribbean, the Central and Eastern Cordilleras and the main intermountain basins (Figure 2). ...
Article
Geochronological databases are powerful tools for characterizing the crustal evolution and the age spectra of a region and allow comparison with other areas at a regional scale. In this contribution, we present the Colombian Geochronological Database (CGD), which contains a curated compilation of ca. 67,406 individual published U-Th-Pb, K-Ar, Ar-Ar, Rb-Sr, Sm-Nd, Lu-Hf, Fission-track, U-Th-He, and Re-Os mineral and whole rock ages that are reported in the published literature. Each date includes geographic coordinates, geological setting, petrologic and chemical information extracted from the respective publications. The structure of the database provides a powerful interface for constructing queries and allows searching and extracting information on geographic domains, provinces, stratigraphic units, isotopic systems, date interpretations, references, etc. This information establishes a framework for regional and global geological interpretations with geochronological, stratigraphic, structural and palaeogeographic implications. With the present effort we present to the geoscience community a clear insight, from a regional perspective, to the geology and tectonics of Colombia since Precambrian times. The comparison of all (detrital and magmatic) single zircon U-Pb dates from the Colombian (Gondwana sourced) geochronological database with the Global and North American (Laurentia sourced) databases provides a temporal constraint on the evolution of the South American continent. U-Pb zircon ages in Colombia define 13 peak clusters centred at 1767, 1530, 1325, 1178, 1007, 605,540, 468, 271, 237, 182, 76 and 10 Ma but of those, only few have a good correlation in all three databases: 1007 (Grenvillian/Orinoquian/Putumayo Orogeny), 605 (Braziliano/Pan-African Orogeny), 468 (Famatinian/Taconic Orogeny), and 182 Ma (Break-up of Pangea) zircon peaks. This correlation suggests that some tectonic events in Colombia are global and might represent crustal production and preservation while the other peaks might just represent local arc magmatic events.
... Complex plate interaction gives rise to a wide deformation zone, extending from Ecuador to Colombia and Venezuela, characterized by both submarine/onshore accretionary wedges and seismically active dextral faults (Alvarado et al., 2016;DeMets et al., 2010;Mora et al., 2017;Pousse-Beltran et al., 2017;Trenkamp et al., 2002). After the study done by Pennington (1981), this Andean sector was considered as a proper microplate: the Northern Andean Block (NAB in Figure 1a), undergoing 0.6 cm/yr NNE-ward (Trenkamp et al., 2002) independent drift with respect to nearby plates (Cediel et al., 2003;Egbue & Kellogg, 2010;Ramos, 2009). ...
Article
Full-text available
GPS data suggest that the NW South America corner forms a semi-rigid block drifting NE-ward along regional dextral strike-slip faults that bound an oceanic terrane accreted in Late Cretaceous times to W Ecuador and Colombia. However, the relevance of both strike-slip versus thrust tectonics during Cenozoic times and their relation with oceanic terrane accretion are unclear. Here we report on the paleomagnetism of 31 mid-upper Eocene to upper Miocene mainly volcanic sites from the Cordilleras Occidental and Real of southern Ecuador. Eleven sites show that the western Cordillera Occidental underwent a 23.9°±9.6° clockwise (CW) rotation with respect to South America after late Miocene times, while no rotation occurred further east. We relate the regional CW rotation to the emplacement of the Cordillera Occidental nappe onto the continental sediments of the Interandean Valley, blanketing the Cordillera’s eastern margin. As rotation and continental sedimentation onset ages are similar, we interpret such tectonic depression as a narrow flexural basin formed ahead of the advancing nappe front. The 20°-30° CW Neogene rotation of the Cordillera Occidental is indistinguishable from the post-Cretaceous rotation of the Coastal forearc oceanic blocks, implying that the whole W Ecuador Andean chain was detached and rotated over a mid-crustal detachment during the last 10 Ma. Eocene-Miocene paleomagnetic inclination values are systematically consistent with those expected for South America, thus excluding latitudinal terrane drift. We suggest that the Andes of Ecuador and Peru form the “Ecuadorian Orocline”, formed by opposing orogenic rotations around the Amazonian craton indenter.
... González de Juana et al. 1980;Kellogg & Bonini 1982;Yrigoyen & Urien 1988;Audemard 2003;Duerto et al. 2006;Monod et al. 2010;Arnaiz-Rodríguez et al. 2011;Dhont et al. 2012;Pérez et al. 2018). As a part of the North Andean Block, the evolution of the MA is thought to be controlled by flat subduction of the shallow (∼40 km) Caribbean slab under northwestern Venezuela (Audemard & Audemard 2002;Monod et al. 2010;Mora et al. 2017). MT studies of orogens often revealed complex resistivity structures, typically associated with active deformation (see Unsworth 2009;Brasse 2011, and references therein). ...
Article
The Caribbean and South American tectonic plates bound the north-eastwards expulsion of the North Andean Block in western Venezuela. This complex geodynamic setting resulted in the formation of major strike-slip fault systems and sizeable mountain chains. The 100-km-wide Mérida Andes extend from the Colombian/Venezuelan border to the Caribbean coast. To the north and south, the Mérida Andes are bound by hydrocarbon-rich sedimentary basins. Knowledge of lithospheric structures, related to the formation of the Mérida Andes, is limited though, due to a lack of deep geophysical data. In this study, we present results of the first broad-band magnetotelluric profile crossing the Mérida Andes and the Maracaibo and Barinas–Apure foreland basins on a length of 240 km. Geoelectrical strike and dimensionality analysis are consistent with 1-D or 2-D subsurface structures for the sedimentary basins but also indicate a strong 3-D setting for the Mérida Andes. Using a combination of 2-D and 3-D modelling we systematically examined the influence of 3-D structures on 2-D inversions. Synthetic data sets derived from 3-D modelling allow identification and quantification of spurious off-profile features as well as smoothing artefact due to limited areal station coverage of data collected along a profile. The 2-D inversion models show electrically conductive basins with depths of 2–5 km for the Barinas-Apure and 2–7 km for the Maracaibo basins. A number of resistive bodies within the Maracaibo basin could be related to active deformation causing juxtaposition of older geological formations and younger basin sediments. The most important fault systems of the area, the Boconó and Valera Faults, cross-cut the Mérida Andes in NE–SW direction along its strike on a length 400 km and N–S direction at its centre on a length 60 km, respectively. Both faults are associated with subvertical zones of high electrical conductivity and sensitivity tests suggest that they reach depths of up to 12 km. A sizeable conductor at 50 km depth, which appears consistently in the 2-D sections, could be identified as an inversion artefact caused by a conductor east of the profile. We speculate the high conductivity associated with the off-profile conductor may be related to the detachment of the Trujillo Block. Our results partially support the ‘floating orogen hypothesis’ developed to explain the geodynamic evolution of western Venezuela and they highlight the relevance of the Trujillo Block in this process.
... Finally, a subducting Caribbean slab was included to the west and north of the study area with 10,000 Ωm and a 10 Ωm accretionary wedge and dehydration zone (Fig. 3c) based on Caribbean subduction models (e.g. Taboada et al., 2000;Mora et al., 2017). ...
Article
The 100 km wide Mérida Andes extend from the Colombian/Venezuelan border to the Coastal Cordillera. The mountain chain and its associated major strike-slip fault systems in western Venezuela formed due to oblique convergence of the Caribbean with the South American Plates and the north-eastwards expulsion of the North Andean Block. Due to the limited knowledge of lithospheric structures related to the formation of the Mérida Andes research projects have been developed to illuminate this zone with deep geophysical data. In this study, we present three-dimensional inversion of broadband magnetotelluric data, collected along a 240 km long profile crossing the Mérida Andes and the Maracaibo and Barinas-Apure foreland basins. The distribution of the stations limits resolution of the model to off-profile features. Combining 3D inversion of synthetic data sets derived from 3D modelling with 3D inversion of measured data, we could derive a 10 to 15 km wide corridor with good lateral resolution to develop hypotheses about the origin of deep-reaching anomalies of high electrical conductivity. The Mérida Andes appear generally as electrically resistive structures, separated by anomalies associated with the most important fault systems of the region, the Boconó and Valera faults. Sensitivity tests suggest that the Valera Fault reaches to depths of up to 12 km and the Boconó Fault to more than 35 km depth. Both structures are connected to a sizeable conductor located east of the profile at 12-15 km depth. We propose that the high conductivity associated with this off-profile conductor may be related to the detachment of the Trujillo Block. We also identified a conductive zone that correlates spatially with the location of a gravity low, possibly representing a SE tilt of the Maracaibo Triangular Block under the mountain chain to great depths (>30 km). The relevance of these tectonic blocks in our models at crustal depths seems to be consistent with proposed theories that describe the geodynamics of western Venezuela as dominated by floating blocks or orogens. Our results stress the importance of the Trujillo Block for the current tectonic evolution of western Venezuela and confirm the relevance of the Boconó Fault carrying deformation to the lower crust and upper mantle. The Barinas-Apure and the Maracaibo sedimentary basins are imaged as electrically conductive with depths of 4 to 5 km and 5 to 10 km, respectively. The Barinas-Apure basin is imaged as a simple 1D structure, in contrast to the Maracaibo Basin, where a series of conductive and resistive bodies could be related to active deformation causing the juxtaposition of older geological formations and younger basin sediments.
... Although factors such as salt withdraw, faulting or shelf morphology can provide a catalyst for mass-wasting (Jabaloy et al., 2003;Posamentier and Martinsen, 2011;Gadol et al., 2019;Bauer et al., 2020;Matenco and Haq, 2020), anomalous, synchronised changes in deposition at convergent margins, particularly abrupt mass-wasting, can signal plate scale re-configurations (Moxon and Graham, 1987;Sevin et al., 2014;Greene and Surpless, 2017;Mora et al., 2017;Englert et al., 2018). The stratigraphic framework presented here not only contains a gradational, tectono-stratigraphic transition between subduction wedge and cover deposition, but stratigraphic indicators of evolving plate margin dynamics as well. ...
Article
Sediments that accumulate within marine basins at convergent plate margins can provide important insights into the evolution and tectonic stability of the subduction wedge. Long-term sediment dispersal and stratigraphic patterns can also be influenced by geodynamic reconfigurations of the plate margin, such as changes in plate dip or velocity, or the subduction of anomalous oceanic crust. An understanding of tectonic context and complexity is therefore critical for any interpretation of convergent margin stratigraphy. Unfortunately, ongoing subduction and wedge deformation tends to obscure or destroy the stratigraphic record of such events as sediments become progressively incorporated within the wedge. The Awatere Valley in New Zealand's South Island contains a well-preserved forearc stratigraphic record that accumulated within coastal-plain and marine basins during the final stages of East Gondwana subduction. We assign seven facies associations (FA) to characterise post-subduction units, showing that a transition from syn to post-subduction deposition is contained within largely marine strata from the New Zealand Urutawan to Ngaterian stages (c. 108 to 95 Ma). In contrast to previous accounts of deposition within nascent rift-basins, restored basin geometries are most consistent with those of terraced subduction wedges. We find no evidence that extension affected deposition prior to 95 Ma. Our results instead document a transition from highly deformed sedimentary wedge (pre 108 Ma) to largely undeformed sedimentary cover units (∼100 Ma) that is predominantly gradational. Up to 2 km of basin fill documents a relative sea-level (RSL) rise and fall between 108 and 95 Ma. A period of relative sediment starvation during the Urutawan (108–103 Ma) was abruptly terminated by synchronous mass-wasting, including the remobilisation of metre-scale blocks and rafts, that signals a dramatic increase in depositional energy relative to preceding patterns. Within the context of a large RSL fluctuation, diminishing compressional tectonism and forearc volcanism (from 98 Ma), this increase is anomalous and appears to signal a significant change in underlying subduction dynamics.
... The northwestern edge of the South American plate is described as an independent block, the Northern Andean Block (NAB; Fig. 1a), which accommodates displacement from the Edirected Nazca subduction and from the ESE-directed Caribbean subduction (Pindell et al., 1988;Taboada et al., 2000;Cediel et al., 2003;Bernal-Olaya et al., 2015;Chiarabba et al., 2016;Syracuse et al., 2016;Mora et al., 2017). The eastern limits of the NAB are the Eastern Cordillera thrust front, the southeastern front on the Andes de Mérida and the Bocono fault in Venezuela (Fig. 1b). ...
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Widespread wrench tectonics has been described along the Northern Andes. The Bucaramanga fault, described as sinistral strike-slip, bounds the high Santander Massif. We combine structural and thermochronologic data at the central-southern portion of the fault, in order to investigate the vertical displacement. Structural survey data shows: 1) old phases of activity preserved in the host rocks along the fault trace, with superimposition of different slickenlines generations; and 2) both strike- and dip-slip kinematics indicators. New and previous thermochronologic data show that differential exhumation of the fault walls has been ongoing from 50 Ma. The hangingwall, the Santander Massif, records: 1) in the central portion, decreasing exhumation rates from the early Miocene to the middle-late Miocene; and 2) in the southern portion, constant rates through the Late Oligocene to the Pliocene. Combining such observations, the thermochronologic offset resulting from the relative motion of the two fault walls is comparable with the observed elevation drop across the fault, suggesting that the present topography of the Santander Massif is related to the vertical movement along the Bucaramanga fault. We infer that the fault has a significant Neogene reverse component, consistent with present-day horizontal GPS vector data, long-term exhumation rates and the structural assemblage.
... This event has been recorded in the EC (Gómez, 2001) and in the WC (León et al., 2018) and now in the CC in this study; in our modelled data sets only. Further, the estimated ~4 km of crustal material that has been eroded from the CC region during the time of deposition in the Amagá basin, implies that most of the detrital material was possibly never deposited locally but the sediments bypassed the basins and were moved along south-to-north drainage system (e.g., Proto-Cauca River) towards formations in the Caribbean realm of northern Colombia (e.g., Sinú San Jacinto Fold Belt (Mora et al., 2017;Osorio-Granada et al., 2020). ...
Article
New zircon and apatite fission-track analyses and aluminium in hornblende thermobarometric data are presented from Cretaceous and Triassic plutons situated along an east-west transect across the Central Cordillera, the Cauca Romeral Fault System and the eastern slopes of the Western Cordillera in the Colombian Andes. The results are combined with published apatite (U–Th)/He ages revealing three episodes of increased cooling during the Late Cretaceous (~110 - 90 Ma), the Eocene (~55-40 Ma) and the Miocene (23-20 Ma). The latter two phases correlate well with the Pre-Andean and Proto-Andean periods previously identified on the basis of stratigraphic unconformities and thermochronology studies in the region. A fourth event, at ~10 Ma, is tentatively recognized in modelled data sets, but not by absolute age values. The thermochronology data imply a total of uplift-driven exhumation (i.e., crustal unroofing) in the study area of up to 10 kms since ~50 Ma at rates of ~0.1 km/Myr and 4 kms since ~23 Ma initially at 0.2 km/Myr. From 10 Ma the rates changed to 0.3–0.33 km/Myr with estimated geothermal gradients of 25–30 °C/km. Thermobarometry data suggest that the crystallization of the Cretaceous intrusions, now at the surface, took place at depths of 8–13 km confirming the amount of exhumation revealed by low-temperature thermochronology.
... It is well known that the northern margin of the NWCSA is convergent, subject to subduction during the Paleogene [54], [80], Ec o p e t r ol [81]. However, the eastward rate of displacement of the Caribbean Plate seems to remain close or accelerated with respect to the current values of 2 cm/y [82], [83] measured by the GPS campaigns [56], with a very low subduction angle [52]. ...
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The Colombia basin contains large volumes of sediment accumulated during the last 17 My. The use of isochore maps, exploratory wells, micropaleontological and geochronological dates has enabled us to estimate the volumes of sediment and accumulation rates in this basin. The analysis of source of sediments and exhumation data from the Northern Andes of South America led to the definition of areas and thicknesses of material eroded during the Neogene - Quaternary, to obtain volumes or material eroded from the continent that can be correlated with sediment volumes accumulated in the Colombia Basin. The analyzed sediment volumes suggest that during the last 17 My ~72.06x1015 Tons accumulated in the Colombia Basin, while ~ 7.16x1013 Tons accumulated in the continental catchment areas. The sedimentation in the Colombian Basin has occurred at variable rates, with values ranging from 55 MTons/My to 295 MTons/My, with a peak of 803 MTons/My in the early Pleistocene (between 2.4 and 2.2 Ma). The evaluation between the total volumes of sediment accumulated in the offshore and onshore, suggests that in the continental part of the basin less than 4% of the total volume of eroded sediment is trapped and, therefore, the behavior of the accumulation rates calculated in the offshore directly reflect the relief evolution of South America’s Northern Andes. It seems, at large, that the lithospheric convergence rates and subduction angle (South America vs Nazca and Meso Atlantic opening) have controlled the regional exhumation of the Northern Andes, with the exception of the Pleistocene high sedimentation event, which seems to coincide with local events such as the collision of the Panama Arch against Western Antioquia. It may be concluded that thanks to this collision, drainage systems such as those of the Magdalena and Cauca rivers were modified, which resulted in the formation of the Magdalena Submarine Fan.
... Topographic upheavals such as those presented here are known to be a consequence of second-order subduction processes (e.g., Andjić et al., 2019Andjić et al., , 2018Haschke et al., 2006;Knesel et al., 2008;Meffre & Crawford, 2001;Mora et al., 2017). In Honduras, stalled subduction due to the resistance of young, buoyant crust precipitated slab detachment and mantle upwelling, resulting in uplift of a broad plateau to elevations over 800 m (Rogers et al., 2002). ...
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Sedimentary successions deposited within arc-trench gaps (forearcs) record topographic oscillations related to subduction tectonism. The collision of oceanic plateaus can inhibit normal subduction and induce detachment of the subducted oceanic lithosphere (slab), leading to subduction translation or shut-down. Such second-order subduction processes complicate the stratigraphic record making discrete events difficult to resolve, as preserved examples are rare and typically overprinted by deformation. We compiled and averaged (stacked) top subduction wedge (Pahau Terrane) subsidence and paleo water-depth curves from thirty locations containing mid-Cretaceous forearc successions in Marlborough, New Zealand. Subsidence curve stacking proved effective in removing deformation due to normal subduction, allowing for resolution of higher order plate-margin events. The stacked curves reveal a synchronous topographic oscillation affecting over 100 km of the paleo-coastline between 110 and 95 Ma, which penetrated almost 250 km into the forearc hinterland and created up to 3 km of accommodation space. Topographic drawdown and highstand deposition from 110 Ma were followed by rebound and volcanism by 98 Ma, a response to regional tectonism that was compared to theoretical predictions for ridge and plateau collision. We conclude that plate flexure, slab extension and tearing reasonably account for the synchronous topographic oscillation observed, which we attribute Hikurangi Plateau collision. We postulate that collision began east of Marlborough along the present-day Chatham Rise from 110 Ma, producing topographic upheaval and disruption of adjacent sedimentary systems. Sediments deposited contemporaneously along the margin preserve a record of these events and provide a rare insight into evolving mid-Cretaceous plate dynamics.
... Regional changes in deposition marked by abrupt increases in sediment volume and calibre, particularly when coupled with forearc volcanism, can signal second order subduction processes or plate scale reconfigurations (e.g. Delteil et al., 2006;Greene and Surpless, 2017;Kortyna et al., 2014;Mora et al., 2017;Uruski, 2008). For comparison, debrites and olistostromes appear absent from the relatively steep gradients of the modern Hikurangi Margin, despite ongoing subduction of the Hikurangi Plateau (Bailleul et al., 2007;Bland et al., 2015;Burgreen-Chan and Graham, 2014;Paquet et al., 2011). ...
Article
Compression during normal continental-oceanic subduction leads to the development of a rugose subduction wedge landward of the trench. Within the marine forearc, fault-bounded highs across the wedge partition clastic deposition between sub-basins, producing wide variations in sediment thickness over 10’s of kilometres. Partitioning, exacerbated by localised mass-wasting, produces forearc successions that are characterised by a broad spectrum of depositional processes and grainsizes. Second order subduction events (e.g. ridge or plateau collision) can disrupt these processes over several millions of years and elicit depositional responses that are discordant within the forearc stratigraphy. These responses thus constitute stratigraphic signals of such events, but can be difficult to decipher owing to the stratigraphic complexity and inherently destructive nature of marine forearcs. Stratigraphic interpretations for well-preserved clastic and volcanic successions in Marlborough, in New Zealand’s South Island, have long held that between 105 and 95 Ma deposition took place into a series of nascent rift basins, consistent with extension elsewhere in New Zealand. We propose a new stratigraphic framework for Marlborough for the New Zealand Urutawan-Motuan (108.4 to 99.5 Ma) and Ngaterian (99.5 to 95.2 Ma) that instead describes deposition within a coastal plain and attached marine basins during ongoing subduction of the Phoenix Plate. We posit that between 108.4 and 95.2 Ma, hiatus conditions, coarse mass-wasting (including olistostromes), prolific highstand deposition, and forearc exhumation punctuated by forearc volcanism represent a significant disruption of preceding depositional patterns. The synchronicity, long-term cyclicity (1 to 5 Ma) and regional extent of these stratigraphic changes indicate that regional tectonism underpinned deposition, which we attribute to second order subduction events along the mid-Cretaceous convergent margin. The stratigraphic framework presented here is consistent with regional geochronologic, stratigraphic and plate reconstruction data that independently argue for continued Phoenix Plate subduction after 92 and as late as 86 Ma. This study underlines the complexity of plate margin dynamics and the complications produced by second order subduction events. The framework presented here indicates that subduction was contemporaneous with continental extension, which following subduction shutdown led to continental breakup from 85 Ma. A stratigraphic record of these events is preserved within the exhumed forearc in Marlborough, which continued to accumulate sediments despite the profound plate-scale events taking place below.
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Remnants of the Caribbean Large Igneous Plateau (CLIP) are found as thicker than normal oceanic crust in the Caribbean Sea, that formed during rapid pulses of magmatic activity at ~ 91–88 Ma and ~ 76 Ma. Strong geochemical evidence supports the hypothesis that the CLIP formed due to melting of the plume head of the Galápagos hotspot, which interacted with the Farallon (Proto-Caribbean) plate in the east Pacific. Considering the plate tectonics theory, it is expected that the lithospheric portion of the plume-related material migrated within the Proto-Caribbean plate, in a north–north-eastward direction, developing the present-day Caribbean plate. In this research, we used 3D lithospheric-scale, data-integrative models of the current Caribbean plate setting to reveal, for the first time, the presence of positive density anomalies in the uppermost lithospheric mantle. These models are based on the integration of up-to-date geophysical datasets, from the Earth’s surface down to 200 km depth, which are validated using high-resolution free-air gravity measurements. Based on the gravity residuals (modelled minus observed gravity), we derive density heterogeneities both in the crystalline crust and the uppermost oceanic mantle (
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We combine previous data from Mesozoic-Cenozoic outcrops in the Guajira Peninsula of northern Colombia with regional gravity, bathymetric, and seismic interpretations to demonstrate the existence of a 280-km-long western extension of the Great Arc of the Caribbean (GAC) along the continental margin of Colombia. Seismic data reveal an 80- to 100-km-wide domal-shaped basement high which exhibits internal chaotic seismic facies. This elongate and domal-shaped structure extends 1800 km from the Aves Ridge in the Caribbean Sea to the study area in offshore Colombia. The western extension of the GAC in Colombia and western Venezuela is buried by 700 to 3000 m of continental margin sedimentary rocks as a result of the GAC colliding earlier with the Colombian margin (Cretaceous-early Paleogene collision) than its subaerially-exposed eastern extension along the Leeward Antilles Ridge (late Paleogene-Neogene). Our compilation of geologic information from the entire GAC shows that GAC magmatism occurred from 128 to 74 Ma with magmatism ages progressively younger towards the east. Six Upper Eocene to Recent marine seismic sequences overlying the domal basement high of the GAC have been mapped by our analysis of 2400 km of seismic lines and 12 well log data. Based on subsurface mapping correlated with well log information and onland geology in the Guajira Peninsula, these six sequences record four major deformational events: 1) late Eocene rifting in an east-west direction produced half-grabens in the northern part of the area; 2) Oligocene transtension in the southern part of the area expressed by right-lateral Oligocene strike-slip faulting and extensional basin formation; 3) early-middle Miocene transtension; and 4) late Miocene-early Pliocene Andean uplift accompanied by rapid erosion and clastic infilling of offshore basins by the Magdalena delta and deep-sea fan. The significance of this basin framework is discussed for known and inferred hydrocarbon systems.
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The left lateral strike-slip Bucaramanga Fault exhibits a transpressional southern termination located towards the axial zone of the Eastern Cordillera of Colombia, where the Boyacá and Soapaga Faults are also identified as inversion-related structures. To unravel their exhumation history, we obtained apatite and zircon fission-track and (U–Th)/He ages from samples collected along different structural domains, along five vertical profiles. Joint Bayesian inverse modeling of these data reveals at least four different episodes of cooling. These are approximately: (i) 50 ± 5 Ma, (ii) 20 ± 5 Ma, (iii) 12 ± 3 Ma, and (iv) 5 ± 3 Ma. The earliest pulse is associated with reactivation of the Boyacá and Soapaga Faults. The second pulse is related to the age of transpressive reactivation along the southern termination of the Bucaramanga Fault and coincides with a marked increase in relief. The Miocene-Pliocene pulses are related to Bucaramanga Fault strike-slip reactivation. Older fission-track ages previously reported from other areas of the Santander Massif suggest migration of exhumation from north to south. The four cooling episodes identified in this study can be related, within a broader geodynamic context, to interaction between the Cocos, Nazca, Caribbean, and South American plates, and the accretion of large tectonic domains of different affinity (oceanic or continental) against the South American plate during the Cenozoic. Our results are consistent with previous work reported in the Santander Massif. The ages observed in the in-situ data correspond with the ages found in modern river sediments and support a relief development from the Eocene to the present.
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Oblique convergent margins accumulate strike‐slip deformation that controls basin formation and evolution. The Bahia Basin is located offshore, proximal to major strike‐slip fault systems that affect northern Colombia. It lies behind the toe of the modern accretionary prism, where the Caribbean Plate is being subducted obliquely beneath South America. This is the first attempt using 3‐D seismic reflection data to interpret a complex strike‐slip basin at the western end of the southern margin of the Caribbean Plate. Detailed 2‐D and 3‐D seismic mapping of regional unconformities and faults is used to describe the structural geometry, timing, and evolution of extensional and strike‐slip faults, which controlled the formation of the basin. Analysis of the fault zones is coupled with a description of the seismic‐stratigraphic units observed within the Bahia Basin to reconstruct the spatial and temporal evolution of deformation and to evaluate the influence of the pervasive shale tectonics observed in the area. The results, presented as a series of structural‐paleogeographic maps, illustrate an initial stage of transtension that controlled the formation of shale‐withdrawal minibasins from late Oligocene to late Miocene times. The continuous deformation and northward expulsion of the Santa Marta Massif resulted in transpression during Pliocene times, leading to basin inversion and ultimate closure of the basin. Basin evolution along the southern Caribbean oblique, convergent margin, shows the occurrence of a complex interaction between subduction and major‐onshore strike‐slip fault systems and illustrates how strain‐partitioning led to the break‐up and lateral displacement of early accretionary prisms formed along the margin.
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Mesozoic and Cenozoic strata of the San Jacinto Fold Belt (Colombian Caribbean) provide insights about sedimentary environments and paleogeographic evolution in the transition between the northern Andes and the South Caribbean deformed belt. We report new provenance (conventional sandstone petrography, heavy mineral analysis, and detrital zircon U‑Pb geochronology and typology) and micropaleontologic data (palynology, calcareous nannofossils, and foraminifera) in samples collected from the lower Eocene (San Cayetano Formation) and upper Eocene–Oligocene (Toluviejo and Ciénaga de Oro Formations) rocks in boreholes drilled by the Colombian Agencia Nacional de Hidrocarburos as well as from recently exposed Oligocene outcrops from the Ciénaga de Oro Formation. Sandstone petrography shows modal variations, with high feldspar content in the lower Eocene rocks and high quartz content in the Oligocene deposits. This shift in compositional maturity may be due to climatic variations, tectonic activity, and/or changes in source areas. Heavy mineral analyses indicate variations that suggest sources primarily related to felsic igneous and/or low-grade metamorphic and mafic and ultramafic rocks. Zircon U‑Pb geochronology displays age populations mainly in the Late Cretaceous, Late Jurassic, Permian–Triassic, and Precambrian (ca. 900–1500 Ma). In addition, zircon typology analyses indicate that the igneous zircons came primarily from monzogranites and granodiorites. Finally, the micropaleontologic and sedimentary data sets indicate that the sediments were deposited in tropical coastal and shallow marine environments. The sediments were transported by short rivers from the crystalline massifs of the Lower Magdalena Valley and the northern Central Cordillera basements, while distal transport of sediments may have occurred along longer rivers, which brought sediments from southern regions located between the Central and Western Cordilleras.
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Remnants of the Caribbean Large Igneous Plateau (C-LIP) are found as thicker than normal oceanic crust in the Caribbean Sea that formed during rapid pulses of magmatic activity at ∼91–88 and ∼76 Ma. Strong geochemical evidence supports the hypothesis that the C-LIP formed due to melting of the plume head of the Galápagos hotspot, which interacted with the Farallon (Proto-Caribbean) plate in the eastern Pacific. Considering plate tectonics theory, it is expected that the lithospheric portion of the plume-related material migrated within the Proto-Caribbean plate in a north–north-eastward direction, developing the present-day Caribbean plate. In this research, we used 3D lithospheric-scale, data-integrative models of the current Caribbean plate setting to reveal, for the first time, the presence of positive density anomalies in the uppermost lithospheric mantle. These models are based on the integration of up-to-date geophysical datasets from the Earth's surface down to 200 km depth, which are validated using high-resolution free-air gravity measurements. Based on the gravity residuals (modelled minus observed gravity), we derive density heterogeneities both in the crystalline crust and the uppermost oceanic mantle (
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Upper plates of subduction zones commonly respond to flat slab subduction by structural reactivation, magmatic arc disruption, and foreland basin inversion. However, the role of active strike-slip faults in focusing convergent deformation and magmatism in response to oblique flat slab subduction remains less clear. Here, we present new detrital apatite fission-track (dAFT) ages from 12 modern catchments in the eastern Alaska Range, Alaska, USA, to reveal how the dextral Denali fault system has facilitated bedrock exhumation and topographic growth during ca. 30 Ma-to-present oblique flat slab subduction of the Yakutat oceanic plateau. Additionally, a 940 ka (⁴⁰Ar/³⁹Ar whole rock) basalt flow is spatially associated with Cenozoic structures, locally reset AFT ages and provides the first evidence for Quaternary volcanism along the southern flank of the eastern Alaska Range. We integrate our new data with other thermochronologic, geochronologic, and regional geologic datasets to show that (1) most high topography regions in southern Alaska have undergone rapid bedrock cooling and exhumation since ca. 30 Ma; (2) elevated terrain and young cooling are spatially associated with long-lived active strike-slip fault systems; (3) topographic growth associated with strike-slip fault deformation led to local inversion of basin systems and drainage reorganization; (4) the onset of oblique oceanic plateau subduction is coeval with a southward shift in arc magmatism from one region of active strike-slip faulting to another above the northeastern edge of the flat slab; and (5) Quaternary volcanism marks the revival of magmatism in the eastern Alaska Range above the geophysically imaged northeastern edge of the flat slab. Our analysis of the post-30 Ma geologic evolution of southern Alaska demonstrates that strike-slip fault systems that were active at the time of slab flattening evolved into transpression zones that focused bedrock cooling, rock exhumation, and topographic growth.
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The onset of subduction in the Caribbean Plate under the South American Plate allowed the development of an Active Continental Margin; the age of onset, the mechanism and the plates involved are a discussion topic, especially at the Colombian South Caribbean Margin, due to the lack of geological information related to the basement. This article integrates petrographic, geochemical analyses and U/Pb dating of basement samples, in addition to the inclusion of published magnetic anomalies maps from the North of Colombia, in order to generate a compositional distribution map of the basement and determine the presence of a magmatic arc under the sediments of the Lower Magdalena Valley (LMV), which supports the existence of a Late Cretaceous active continental margin represented by a magmatic arc, called Magmatic Arc of Magangué. Dating of the arc yield a Late Cretaceous Age (84-74 Myr), and petrographic and geochemical evidence suggests it is comprised of igneous bodies of felsic to intermediate composition, which intrude the LMV continental crust, originated in a subduction setting. The origin of the LMV continental crust seems to be related to the continent-continent collision (consolidation of Pangaea) during the Permian (300 Ma ago), and to the post-Alleganian extension event of Triassic age (232 Ma ago).
Poster
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The Eocene succession of northern South America was characterized by a complex tectonic configuration developing provinces with characteristic structural and tectonic features which have petroleum potential. One of these provinces is the Sinu-San Jacinto Basin. It is located in the north of Colombia and is composed of Late Cretaceous to Holocene sediments in the San Jacinto Folded Belt and sediments not older than late Oligocene in the Sinu Folded Belt. For the purpose of contributing to the knowledge about paleo-environmental conditions for early-middle Eocene succession in the Sinu-San Jacinto Basin, we analyzed the planktonic and benthic foraminifera from samples of the Chengue Formation in two stratigraphic sections. Microfaunas analyzed were composed of abundant planktonic and benthic foraminifera, where the benthic foraminifera with hyaline wall were the most common. Foraminiferal assemblages were characterized mainly by planktonic specimens of Clavigerinella akersi, C. colombiana, Pseudoglobigerinella bolivariana, Acarinina pentacamerata, Morozovella aragonensis, Igorina broedermanni, Paragloborotalia nana and P. griffinoides. Benthic foraminifera were represented by Bolivina spp., Bulimina spp., Uvigerina spp., Hanzawaia spp., Cibicides spp. and specimens of Nodosariacea. Environmental conditions were estimated from paleo- bathymetric analyses, diversity analyses, planktonic and benthic foraminifera ratio, triangular plots for the foraminiferal assemblage structure based on types of wall textures in benthic foraminifera, epifauna/infauna ratio and other ecologic characteristics of foraminifera. The interpretation of the depositional environment suggests that the sediments analyzed from the Chengue Formation (early-middle Eocene) were deposited in neritic environments of shelf with possible variations to bathyal environments (upper-middle slope). The results match with previous analyses in this basin which propose neritic environments with possible variations from transitional to shelf. However, they do not suggest possible changes to bathyal environments from upper to middle slope, as proposed by this study. Moreover, the presence of planktonic foraminifera as Clavigerinella spp., Pseudoglobigerinella bolivariana and Paragloborotalia griffinoides could indicate that the depositional environment was characterized by high biological productivity probably associated with upwelling events. Finally, high abundances of Bolivina spp., Bulimina spp., Uvigerina spp. and specimens of Nodosariacea suggest environments with low oxygen levels.
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Abs tract We present the results of 59 new apatite fission tracks (AFT), 24 new vitrinite reflectance analysis, and 154 new He thermocronometric analysis from the eastern flank of the Colombian eastern Cordillera at lat7° N to constrain the roles of plate tectonics, tectonic inheritance, and surface processes in building the Cocuy syntaxis. The Cocuy syntaxis is the region with the highest structural and topographic relief in the eastern Cordillera. The primary factor controlling that is faster tectonism, apparently related to the most important Panama collision at 4 Ma. This push from behind is focused between two resistant plates and escapes toward a weak foreland plate, which is able to flex. However, we document new Pliocene and younger AFT ages in the eastern side of the eastern Cordillera, which are related with focused and faster exhumation in the eastern flank. We suggest that this episode is responsible for the limited advance of the deformation front as basement-involved blocks. In addition, faster denudation causes faster sedimentation rates in the weak foreland plate east of the Cocuy syntaxis. In this case, the thick pile of Neogene synkinematic sediments would have limited thin skin deformation migration.
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Global Positioning System (GPS) data from southern Central America and northwestern South America were collected during 1991, 1994, 1996, and 1998 in Costa Rica, Panama, Ecuador, Colombia and Venezuela. These data reveal wide plate boundary deformation and escape tectonics occurring along an approximately 1400 km length of the North Andes; locking of the subducting Nazca plate and strain accumulation in the Ecuador-Colombia forearc; ongoing collision of the Panama arc and Colombia; and convergence of the Caribbean plate with Panama and South America. Elastic modeling of observed horizontal displacements in the Ecuador forearc is consistent with partial locking (50%) in the subduction zone and partial transfer of motion to the overriding South American plate. The deformation is hypothesized to reflect elastic recoverable strain accumulation associated with the historic seismicity of the area and active faulting associated with permanent shortening of 6 mm/a. Deformation associated with the Panama-Colombia collision is consistent with elastic strain accumulation on a fully locked Atrato-Uraba Fault Zone (AUFZ) suture.
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Seismicity at the northern terminus of the Nazca subduction is diffused over a wide area containing the puzzling seismic feature known as the Bucaramanga nest. We relocate about 5000 earthquakes recorded by the Colombian national seismic network and produce the first 3-D velocity model of the area to define the geometry of the lithosphere subducting below the Colombian Andes. We found lateral velocity heterogeneities and an abrupt offset of the Wadati-Benioff zone at 5°N indicating that the Nazca plate is segmented by an E-W slab tear, that separates a steeper Nazca segment to the south from a flat subduction to the north. The flat Nazca slab extends eastward for about 400 km, before dip increases to ∼50° beneath the Eastern Cordillera, where it yields the Bucaramanga nest. We explain this puzzling locus of intermediate-depth seismicity located beneath the Eastern Cordillera of Colombia as due to a massive dehydration and eclogitization of a thickened oceanic crust. We relate the flat subducting geometry to the entrance at the trench at ca. 10 Ma of a thick - buoyant oceanic crust, likely a volcanic ridge, producing a high coupling with the overriding plate. Sub-horizontal plate subduction is consistent with the abrupt disappearance of volcanism in the Andes of South America at latitudes>5°N.
Thesis
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The Santa Fé de Antioquia – Dabeiba section offers a complete view troughout the different units of the Western Cordillera of Colombia, including, from base to top, an oceanic-crust basin associated with the Barroso Formation (Aptian-early Coniacian) and a sedimentary cover from the late Cretaceous (late Campanian-early Paleocene), the Penderisco Formation. This unit is divided into an inferior, clastic part, the Urrao Member which is the product of the deposition of hyperpycnical flows in a continental slope, and the upper fine-grained, calcareous and siliceous with volcanic intercalations Nutibara Member. This sequences sum a considerable thickness of aproximatedly 8.560 m overcoming the dimension of the Cretaceous basins, like the Eastern Cordillera of Colombia, which thickness varies from 3.000 m to 6.000 m. The opening of this sedimentary basin occurred due to the formation of an Antiform during the early Campanian, which is marked by the end of the deposition of the Barroso Formation, coinciding with the blockade of the subduction between the South American and Caribe Plates.
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High-grade basement massifs exposed in the northern Andes and the buried basement of the adjacent Putumayo foreland basin contain a record of Amazonia's involvement in the supercontinent Rodinia. Metasedimentary granulites and orthogneisses, strongly deformed during at least one metamorphic episode dated at ca. 0.99 Ga, provide critical information on the pre-collisional history of the Mesoproterozoic continental margin. Here, new U-Pb, Lu-Hf, Sm-Nd and O isotopic data from outcrop samples of the Garzon and Las Minas Cordilleran basement massifs as well as fragments of drill-core recovered from the Putumayo basin basement are reported. We explore the application of a dual-ICP-MS approach to obtain concurrent U-Pb and Lu-Yb-Hf information on complexly zoned zircon from orogenic lower-crust, and demonstrate its use to retrieve reliable pre-metamorphic information despite possible complexities introduced by mixed-domain ablation and isotopic disturbance of the U-Pb system by thermally induced recrystallization. In combination with delta O-18 compositions from the same zircon growth domains, and bulk-rock Nd isotope information, we reconstruct segments of the tectonic and crustal evolution of a long-lived accretionary orogen that developed along the (modern) NW margin of Amazonia during most of the Mesoproterozoic. Inherited zircons in metaigneous samples from the Cordilleran massifs, with protolith crystallization ages in the range from ca. 1.47 to 1.15 Ga, have Hf-O compositions that indicate significant crustal reworking in their source region, but denote a trend of increasing Hf-176/Hf-177 with decreasing age that can be attributed to rejuvenation by progressive addition of radiogenic components during this time interval. Detrital zircons within this same age range found in metasedimentary granulites of the Garzon massif also follow this trend, further supporting previous inferences that their protoliths were deposited in arc-proximal basins with little to no coarse-grained detritus delivered from an older cratonic domain. A shift in orogenic deformation style starting at similar to 1.15-1.10 Ga, inferred to be associated with the accretion of fringing-arc terranes against the continental margin, triggered an early amphibolite-grade metamorphic episode; this was accompanied by pervasive partial melting and migmatite development in fertile metasedimentary units and is interpreted to be responsible for enhanced crustal reworking evidenced from the shallowing of Hf-176/Hf-177 vs. age trends in detrital and metamorphic zircons from the Garzon and Las Minas massifs. Convergent tectonism along the Putumayo margin came to an end during the final incorporation of Amazonia to the core of the Rodinia supercontinent, possibly during collision against the Sveconorwegian segment of Baltica at 0.99 Ga. Although the position and role of Amazonia within Rodinia remains controversial, the new Nd and Hf isotope data provide additional evidence to link the evolution of this orogenic segment with the basement of Oaxaquia, as well as continue to draw fundamental differences with the timing and nature of the tectonic processes associated with the development of the Sunsas-Aguapei Orogen of SW Amazonia. (C) 2015 Elsevier B.V. All rights reserved.
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A B S T R A C T In Colombia, palynology has been widely used as a biostrati-graphic tool in oil exploration over the last two decades and, as a result of these efforts, an understanding of the chronostratigraphic range of thousands of palynomorph species is now available. Furthermore, because of their relative resistance to physical and chemical degradation, palynomorphs can often survive several tectonic-erosive cycles, allowing them to be used as unique tracers of long-term sedimentological changes. In this work, we use the palynological record from wells and outcrops in the Llanos foot-hills and the Llanos basin of Colombia to establish the intensity of Cenozoic reworking and its relationship to the tectonic evolution of the Colombian Andes. Using this approach, we were able to discern several tectonic episodes associated with the uplift of the Eastern Cordillera. We documented three periods of either faster erosion in the hinterland or more widespread areas being eroded in the catchment areas (late Paleocene–early Eocene, early to mid Miocene and Pliocene) and two periods of tectonic quiescence (mid-Eocene and mid–late Miocene). These periods correlate well with the deposition of different elements of the petroleum systems in the Llanos basin of Colombia (seals and reservoirs).
Technical Report
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The Geological Map of Colombia (GMC) 2007 summarizes the superficial geological information of the Colombian territory, was compiled using ArcGIS 8.3 by integration and generalization of 1:100,000 scale geological sheets published by INGEOMINAS. The harmonization was controlled using remote sensing imagery such as Landsat, radar and a 30 m resolution NASA SRTM DEM. The units represented on the GMC were defined according to a mixed chronostratigraphic–lithostratigraphic classificatory outline that took into account age, lithology and province to the basements rocks. As a result of the compiled information analysis for the GMC, evolutionary models that consider the configuration of the Colombian territory by multiple accretions are supported. In particular, the GMC allows postulating the accretion of four crustal blocks —three of them of oceanic affinity— to the northwestern edge of autochthonous Gondwana. Such accretion episodes occurred possibly in Neoproterozoic, the two older ones, whereas the last two episodes occurred during the Paleogene. For the handling of the GMC’s data it was designed a digital model that in addition to its character as an independent GIS to be use with ArcMap–ArcGIS, could be implemented into a corporate geodatabase integrated to the GIS of INGEOMINAS (SIGER). The technological platform that supports the SIGER is based on the database management systems Oracle 8i and ArcSDE 8.3 for the handling of the data, and on ArcGIS 9.1 for their spatial treatment. The GMC brings a scientific and institutional vision that will allow strengthening of the geoscientific lines of research that the country needs to improve the knowledge of its underground resources and sustainable development.
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Plateau related rocks accreted to the Caribbean plate margins provide insights into the understanding of the intra-oceanic evolution of the Caribbean plate and its interaction with the continental margins of the Americas. Petrologic, geochemical and isotope (Sr and Nd) data were obtained in rocks from the Santa Fé Gabbro-Tonalite and Buriticá Tonalite in the Western Cordillera of Colombia. Field relations and whole rock–mineral geochemistry combined with juvenile isotope signatures of the different rocks present in the area, suggest that initial melts, represented by the Buriticá Tonalite, formed due to asthenospheric upwelling at ∼100 Ma, which intrude the Colombian-Caribbean Oceanic Plateau (CCOP) basalts, and subsequent migration of the Caribbean plate towards the northeast resulted in subduction initiation and the formation of the Santa Fé tonalitic units at ∼90 Ma on the CCOP. The relation of the Santa Fé Batholith with other units from the Caribbean, such as Aruba and the Buga Batholiths suggests the existence of an immature arc constructed on the Caribbean Plateau, which partially accreted onto a continental margin of South American in pre-Eocene times, or migrated to the present day position in the Lesser Antilles.
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Uranium-lead geochronology in detrital zircons and provenance analyses in eight boreholes and two surface stratigraphic sections in the northern Andes provide insight into the time of closure of the Central American Seaway. The timing of this closure has been correlated with Plio-Pleistocene global oceanographic, atmospheric, and biotic events. We found that a uniquely Panamanian Eocene detrital zircon fingerprint is pronounced in middle Miocene fluvial and shallow marine strata cropping out in the northern Andes but is absent in underlying lower Miocene and Oligocene strata. We contend that this fingerprint demonstrates a fluvial connection, and therefore the absence of an intervening seaway, between the Panama arc and South America in middle Miocene times; the Central American Seaway had vanished by that time. Copyright © 2015, American Association for the Advancement of Science.
Article
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The Caribbean oceanic crust was formed west of the North and South American continents, probably from Late Jurassic through Early Cretaceous time. Its subsequent evolution has resulted from a complex tectonic history governed by the interplay of the North American, South American and (Paleo-)Pacific plates. During its entire tectonic evolution, the Caribbean plate was largely surrounded by subduction and transform boundaries, and the oceanic crust has been overlain by the Caribbean Large Igneous Province (CLIP) since ~ 90 Ma. The consequent absence of passive margins and measurable marine magnetic anomalies hampers a quantitative integration into the global circuit of plate motions. Here, we present an updated, quantitatively described kinematic reconstruction of the Caribbean region back to 200 Ma, integrated into the global plate circuit, and implemented with GPlates free software. Our reconstruction includes description of the tectonic units in terms of Euler poles and finite rotation angles. Our analysis of Caribbean tectonic evolution incorporates an extensive literature review. To constrain the Caribbean plate motion between the American continents, we use a novel approach that takes structural geological observations rather than marine magnetic anomalies as prime input, and uses regionally extensive metamorphic and magmatic phenomena such as the Great Arc of the Caribbean, the CLIP and the Caribbean high-pressure belt as correlation markers. The resulting model restores the Caribbean plate back along the Cayman Trough and major strike-slip faults in Guatemala, offshore Nicaragua, offshore Belize and along the Northern Andes towards its position of origin, west of the North and South American continents in Early Cretaceous time. We provide the paleomagnetic reference frame for the Caribbean region by rotating the Global Apparent Polar Wander Path into coordinates of the Caribbean plate interior, Cuba, and the Chortis Block. We conclude that formation of the Caribbean plate, west of the North and South Americas, as a result of Panthalassa/Pacific spreading leads to a much simpler plate kinematic scenario than Proto-Caribbean/Atlantic spreading. Placing our reconstruction in the most recent mantle reference frames shows that the CLIP originated 2000-3000 km east of the modern Galápagos hotspot, and may not have been derived from the corresponding mantle plume. Finally, our reconstruction suggests that most if not all modern subduction zones surrounding the Caribbean plate initiated at transform faults, two of these (along the southern Mexican and NW South American margins) evolved diachronously as a result of migrating trench-trench-transform triple junctions.
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Northwestern South America preserves a record of the assembly of western Pangaea, its disassembly and initiation of the far western Tethys Wilson Cycle, subsequent Pacific margin magmatism and ocean plateaucontinent interaction since the Late Cretaceous. Numerous models have been presented for various time slices although they are based on either spatially restricted datasets, or dates that are inaccurate estimates of the time of crystallisation. Here we review a very large quantity of geochronological, geochemical, thermochronological, sedimentological and palaeomagnetic data that collectively provide tight constraints for geological models. These data have been collected over a trench (Pacific)-parallel distance of >1500 km (Colombia and Ecuador), and reveal important temporal trends in rifting and subduction. The temporal framework for our model constraints are obtained from robust concordant zircon U-Pb ages of magmatic rocks during 290-75 Ma. The Late Cretaceous thermal history of the margin (<350 degrees C) is described by Ar-40/Ar-39 and fission track data, and the higher temperature and thus older (pre-75 Ma) history are constrained by apatite U-Pb thermochronology. Variations in the isotopic compositions of Hf (zircon), Nd (whole) and 0 (quartz) with time have been used to track the evolution of the source of magmatism, and are used as proxies for crustal thickness. Atomic chemical compositions, combined with isotopes and dense mineral assemblages are used to differentiate between continental and oceanic environments. These data show that rifting within western Pangaea started at 240 Ma, leading to sea floor spreading between blocks of Central and South America by 216 Ma. Pacific active margin commenced at 209 Ma, and continued until 115 Ma above an east-dipping subduction zone that was rolling back, attenuating South America and forming new continental crust. The opening of the South Atlantic drove South America westwards, compressed the Pacific margin of northwestern South America at 115 Ma and obducted an exhumed subduction zone. Passive margin conditions prevailed until the Oceanic Plateau and its overlying intra-oceanic arc (The Rio Cala Arc) collided and accreted to South America at 75 Ma.
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Crustal anatectites are frequently observed along ocean–continent active margins, although their origins are disputed with interpretations varying between rift-related and collisional. We report geochemical, isotopic and geochronological data that define an ~ 1500 km long belt of S-type meta-granites along the Andes of Colombia and Ecuador, which formed during 275–223 Ma. These are accompanied by amphibolitized tholeiitic basaltic dykes that yield concordant zircon U–Pb dates ranging between 240 and 223 Ma. A model is presented which places these rocks within a compressive Permian arc setting that existed during the amalgamation of westernmost Pangaea. Anatexis and mafic intrusion during 240–223 Ma are interpreted to have occurred during continental rifting, which culminated in the formation of oceanic crust and initiated the break-up of western Pangaea. Compression during 275–240 Ma generated small volumes of crustal melting. Rifting during 240–225 Ma was characterized by basaltic underplating, the intrusion of tholeiitic basalts and a peak in crustal melting. Tholeiitic intrusions during 225–216 Ma isotopically resemble depleted mantle and yield no evidence for contamination by continental crust, and we assign this period to the onset of continental drift. Dissected ophiolitic sequences in northern Colombia yield zircon U–Pb dates of 216 Ma. The Permo-Triassic margin of Ecuador and Colombia exhibits close temporal, faunal and geochemical similarities with various crustal blocks that form the basement to parts of Mexico, and thus these may represent the relict conjugate margin to NW Gondwana. The magmatic record of the early disassembly of Pangaea spans ~ 20 Ma (240–216 Ma), and the duration of rifting and rift–drift transition is similar to that documented in Cretaceous–Tertiary rift settings such as the West Iberia–Newfoundland conjugate margins, and the Taupo–Lau–Havre System, where rifting and continental disassembly also occurred over periods lasting ~ 20 Ma.
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En estudios estratigráficos realizados recientemente en las secciones del Arroyo Alférez (Cretáceo - Paleogeno) y la de Carmen - Zambrano (Paleogeno - Neogeno), situadas en la Costa Norte de Colombia, ha sido posible reconocer variaciones cíclicas en el contenido de carbonato de calcio. Esto se ha interpretado, entre otras causas, como debido a la solución diferencial y descalcificación de la fauna, consecuencia directa del aumento en la profundidad de la cuenca. Teniendo en cuenta este fenómeno, se plantean dos ciclos tectónicos y sedimentarios separados por períodos de tectonismo intenso y erosión, los cuales están confirmados por cambios paleoecológicos bruscos en los ambientes de depósito. Estos ciclos se pueden comparar en un sentido general con las Facies geosinclinales de Auboin (1965) y sirven como unidades estratigráficas prácticas para correlaciones regionales. De esta manera los ciclos reconocidos se proponen como unidades tiempo – roca.
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We combine previous data from Mesozoic-Cenozoic outcrops in the Guajira Peninsula of northern Colombia with regional gravity, bathymetric, and seismic interpretations to demonstrate the existence of a 280-km-long western extension of the Great Arc of the Caribbean (GAC) along the continental margin of Colombia. Seismic data reveal an 80- to 100-km-wide domal-shaped basement high which exhibits internal chaotic seismic facies. This elongate and domal-shaped structure extends 1800 km from the Aves Ridge in the Caribbean Sea to the study area in offshore Colombia. The western extension of the GAC in Colombia and western Venezuela is buried by 700 to 3000 m of continental margin sedimentary rocks as a result of the GAC colliding earlier with the Colombian margin (Cretaceous-early Paleogene collision) than its subaerially-exposed eastern extension along the Leeward Antilles Ridge (late Paleogene-Neogene). Our compilation of geologic information from the entire GAC shows that GAC magmatism occurred from 128 to 74 Ma with magmatism ages progressively younger towards the east. Six Upper Eocene to Recent marine seismic sequences overlying the domal basement high of the GAC have been mapped by our analysis of 2400 km of seismic lines and 12 well log data. Based on subsurface mapping correlated with well log information and onland geology in the Guajira Peninsula, these six sequences record four major deformational events: 1) late Eocene rifting in an east-west direction produced half-grabens in the northern part of the area; 2) Oligocene transtension in the southern part of the area expressed by right-lateral Oligocene strike-slip faulting and extensional basin formation; 3) early-middle Miocene transtension; and 4) late Miocene-early Pliocene Andean uplift accompanied by rapid erosion and clastic infilling of offshore basins by the Magdalena delta and deep-sea fan. The significance of this basin framework is discussed for known and inferred hydrocarbon systems.
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Subducting plates around the globe display a large variability in terms of slab geometry, including regions where smooth and little variation in subduction parameters is observed. While the vast majority of subduction slabs plunge into the mantle at different, but positive dip angles, the end-member case of flat-slab subduction seems to strongly defy this rule and move horizontally several hundreds of kilometers before diving into the surrounding hotter mantle. By employing a comparative assessment for the Mexican, Peruvian and Chilean flat-slab subduction zones we find a series of parameters that apparently facilitate slab flattening. Among them, trench roll-back, as well as strong variations and discontinuities in the structure of oceanic and overriding plates seem to be the most important. However, we were not able to find the necessary and sufficient conditions that provide an explanation for the formation of flat slabs in all three subduction zones. In order to unravel the origin of flat-slab subduction, it is probably necessary a numerical approach that considers also the influence of surrounding plates, and their corresponding geometries, on 3D subduction dynamics.
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Detailed interpretations of reflection seismic data and new U-Pb and Hf isotope geochemistry in zircon, reveal that the basement of the Lower Magdalena Valley basin is the northward continuation of the basement terranes of the northern Central Cordillera, and thus that the Lower Magdalena experienced a similar pre-Cenozoic tectonic history as the latter. New U-Pb and Hf analyses of zircon from borehole basement samples retrieved in the basin show that the southeastern region consists of Permo-Triassic (232-300Ma) metasediments, which were intruded by Late Cretaceous (75–89 Ma) granitoids. In the northern Central Cordillera, west of the Palestina Fault System, similar Permo-Triassic terranes are also intruded by Late Cretaceous felsic plutons and display ESE-WNW-trending structures. Therefore, our new data and analyses prove not only the extension of the Permo-Triassic Tahamí-Panzenú terrane into the western Lower Magdalena, but also the along-strike continuity of the Upper Cretaceous magmatic arc of the northern Central Cordillera, which includes the Antioquia Batholith and related plutons. Hf isotopic analyses from the Upper Cretaceous Bonga pluton suggest that it intruded new crust with oceanic affinity, which we interpret as the northern continuation of a Lower Cretaceous oceanic terrane (Quebradagrande?) into the westernmost Lower Magdalena. Volcanic andesitic basement predominates in the northwestern Lower Magdalena while Cretaceous low-grade metamorphic rocks that correlate with similar terranes in the Sierra Nevada de Santa Marta and Guajira are dominant in the northeast, suggesting that the Tahamí-Panzenú terrane does not extend into the northern Lower Magdalena. Although the northeastern region of the Lower Magdalena has a similar NE-SW fabric as the San Lucas Ridge of the northeastern Central Cordillera and the Sierra Nevada de Santa Marta, lithologic and geochronologic data suggest that the San Lucas terrane terminates to the north against the northeastern Lower Magdalena, as the Palestina Fault System bends to the NE. The NE-SW trend of basement faults in the northeastern Lower Magdalena is probably inherited from the Jurassic rifting event which is responsible for the conspicuous fabric of surrounding terranes outcropping to the east of the Palestina Fault System, while the ESE-WNW trend in the western Lower Magdalena is inherited from a Late Cretaceous to Eocene strike-slip and extension episode that is widely recognized in the western Andean forearc from Ecuador to Colombia.
Article
Between the Late Cretaceous and Paleogene, the Northern Andes experienced subduction and collision due to the convergence between the oceanic Caribbean Plate and the continental margin of Ecuador and Colombia. Subduction-related calc-alkaline plutonic rocks form stocks of limited areal expression or local batholiths that consist mostly of diorites and granodiorites. We investigated two stocks (Hatillo and Bosque) exposed in the Central Cordillera of Colombia that had U–Pb zircon crystallization ages between 60 and 53 Ma. Relatively low radiogenic Sr, Nd and Pb isotopes from selected samples account for a heterogeneous crustal source, whereas negative anomalies of Nb and Ti, high LREE/HREE and Sr/Y > 28 ratios indicate that the magmas were emplaced in a continental magmatic arc setting. ƐHf(i) values of the dated zircons were between − 4 and + 7 and suggest some contamination of the magmas during their ascent through the crust. The high Sr/Y ratios recorded both in the investigated plutons as well as in other Paleogene plutons in the Central Cordillera suggest that the magmas differentiate in high-pressure conditions (garnet stability field). This differentiation probably occurred at the base of a thickened crust through the Mesozoic subduction and accretion of oceanic arcs to the continental margin during the Lower Cretaceous and Paleocene. The existence of other Paleogene granitoids with evidence of shallower differentiation signatures may be also an inheritance of along strike variations in the Northern Andean continental crust due to Cretaceous to Paleogene oblique convergence. The Hf isotope results from Paleogene detrital zircons from volcanoclastic rocks of the eastern Colombian basins reinforce the possibility of a distal magmatic focus.
Article
The structure, stratigraphy and magmatic history of northern Peru, Ecuador and Colombia are only adequately explained by Pacific-origin models for the Caribbean Plate. Inter-American models for the origin of the Caribbean Plate cannot explain the contrasts between the Northern Andes and the Central Andes. Persistent large magnitude subduction, arc magmatism and compressional deformation typify the Central Andes, while the Northern Andes shows back-arc basin and passive margin formation followed by dextral oblique accretion of oceanic plateau basalt and island arc terranes with Caribbean affinity. Cretaceous separation between the Americas resulted in the development of a NNE-trending dextral–transpressive boundary between the Caribbean and northwestern South America, becoming more compressional when spreading in the Proto-Caribbean Seaway slowed towards the end of the Cretaceous. Dextral transpression started at 120–100 Ma, when the Caribbean Arc formed at the leading edge of the Caribbean Plate as a result of subduction zone polarity reversal at the site of the pre-existing Trans-American Arc, which had linked to Central America to South America in the vicinity of the present-day Peru–Ecuador border. Subsequent closure of the Andean Back-Arc Basin resulted in accretion of Caribbean terranes to western Colombia. Initiation of flat-slab subduction of the Caribbean Plate beneath Colombia at about 100 Ma is associated with limited magmatism, with no subsequent development of a magmatic arc. This was followed by northward-younging Maastrichtian to Eocene collision of the trailing edge Panama Arc. The triple junction where the Panama Arc joined the Peru–Chile trench was located west of present-day Ecuador as late as Eocene time, and the Talara, Tumbes and Manabi pull-apart basins directly relate to its northward migration. Features associated with the subduction of the Nazca Plate, such as active calc-alkaline volcanic arcs built on South American crust, only became established in Ecuador, and then Colombia, as the triple junction migrated to the north. Our model provides a comprehensive, regional and testable framework for analysing the as yet poorly understood collage of arc remnants, basement blocks and basins in the Northern Andes.
Article
Many aspects of deep-time Earth System models, including mantle convection, paleoclimatology, paleobiogeography and the deep Earth carbon cycle, require high-resolution plate models that include the evolution of the mosaic of plate boundaries through time. We present the first continuous late Paleozoic to present-day global plate model with evolving plate boundaries, building on and extending two previously published models for the late Paleozoic (410–250 Ma) and Mesozoic-Cenozoic (230–0 Ma). We ensure continuity during the 250–230 Ma transition period between the two models, update the absolute reference frame of the Mesozoic-Cenozoic model and add a new Paleozoic reconstruction for the Baltica-derived Alexander Terrane, now accreted to western North America. This 410–0 Ma open access model provides a framework for deep-time whole Earth modelling and acts as a base for future extensions and refinement.
Presentation
The integrated analysis of seismic, well log and outcrop data from the Cenozoic section of the northern San Jacinto Fold belt (SJFB) in NW Colombia, revealed a complex tectonic evolution from Paleogene extension to Neogene compression and inversion. Interpretation of the first 3D-seismic survey in the SJFB allowed the best imaging and most detailed mapping to date of the pre-Oligocene structure and potential reservoirs. This was complemented by the interpretation of new 2D-seismic in the northernmost portion of the SJFB. Paleocene to Miocene units contain both potential source rocks and main reservoirs, though Cretaceous source rocks may also be active in the area. Six main second-order sequences of Late Paleocene to Pliocene age were identified in the northern SJFB. The San Cayetano sequence (Late Paleocene-Middle Eocene) was deposited in marine environments and lies unconformably on top of the Cretaceous. In the Middle to Late Eocene, conglomerates and limestones of the Chengue Group were unconformably deposited on top of San Cayetano. 3D-seismic data shows that the Chengue Group was deposited in an extensional fault-controlled regime, as evidenced by planar domino-faulting. After Latest Eocene-Early Oligocene erosion, fine-grained deposits of the Late Oligocene Ciénaga de Oro Sequence onlap the pre-existing paleo-topography, as the area continues subsiding due to sagging. In Early Miocene times, the first compressive event caused initial inversion of pre-existing extensional structures. While pre-Oligocene extensional structures are well preserved in the area of the 3D, inversion is much more intense towards the north, where the pre-Oligocene sequences are affected by more recent WNW-verging thrust faults. The syn-inversion marine, fine-grained Porquero sequences of Middle-Late Miocene age, evidence intense inversion of structures such as the Cibarco Anticline, as they thin and onlap its eastern flank. In the Late Miocene, extensional faulting commonly detaching in Ciénaga de Oro mudstones, affected the Porquero Sequences possibly due to gravitational sliding caused by uplift in other areas. Therefore, the Ciénaga de Oro marks the boundary between two contrasting extensional structural styles. A notorious angular unconformity marks the base of the Tubará Sequence, a Latest Miocene - Pliocene succession of fluvial to shallow marine deposits, that evidences strong inversion pulses which started to shape the present-day topography of the northern SJFB.
Article
Most of the plate boundaries are activated obliquely with respect to the direction of far field stresses, as roughly only 8% of the plate boundary total length shows a very low obliquity (ranging from 0 to 10°, sub-orthogonal to the plate displacement). The obliquity along plate boundaries is controlled by (i) lateral rheological variations within the lithosphere and (ii) consistency with the global plate circuit. Indeed, plate tectonics and magmatism drive rheological changes within the lithosphere and consequently influence strain localization. Geodynamical evolution controls large-scale mantle convection and plate formation, consumption, and re-organization, thus triggering plate kinematics variations, and the adjustment and re-orientation of far field stresses. These geological processes may thus result in plate boundaries not perpendicular to the direction of far field stresses, i.e. to obliquity of deformation. This paper reviews the global patterns of obliquity along plate boundaries. Using GPlate, we provide a statistical analysis of present-day obliquity along plate boundaries. Within this framework, by comparing natural examples and geological models, we discuss deformation patterns and kinematics recorded along oblique plate boundaries.
Article
Subduction beneath the northernmost Andes in Colombia is complex. Based on seismicity distributions, multiple segments of slab appear to be subducting, and arc volcanism ceases north of 5° N. Here, we illuminate the subduction system through hypocentral relocations and Vp and Vs models resulting from the joint inversion of local body wave arrivals, surface wave dispersion measurements, and gravity data. The simultaneous use of multiple data types takes advantage of the differing sensitivities of each data type, resulting in velocity models that have improved resolution at both shallower and deeper depths than would result from traditional travel time tomography alone. The relocated earthquake dataset and velocity model clearly indicate a tear in the Nazca slab at 5° N, corresponding to a 250-km shift in slab seismicity and the termination of arc volcanism. North of this tear, the slab is flat, and it comprises slabs of two sources: the Nazca and Caribbean plates. The Bucaramanga nest, a small region of among the most intense intermediate-depth seismicity globally, is associated with the boundary between these two plates and possibly with a zone of melting or elevated water content, based on reduced Vp and increased Vp/Vs. We also use relocated seismicity to identify two new faults in the South American plate, one related to plate convergence and one highlighted by induced seismicity.
Article
New apatite U-Pb and multiphase 40Ar/39Ar data constrain the high to medium temperature (~ 500 °C - ~ 300 °C) thermal histories of igneous and metamorphic rocks exposed in the Mérida Andes of Venezuela, and new apatite and zircon fission track data constrain the ~ 500 °C - ~ 60 °C thermal histories of pre-Jurassic igneous and metamorphic rocks of the adjacent Santander Massif of Colombia. Computed thermal history envelopes using apatite U-Pb dates and grain size information from an Early Palaeozoic granodiorite in the Mérida Andes suggest that it cooled from > 500 °C to < 350 °C between ~ 266 Ma and ~ 225 Ma. Late Permian to Triassic cooling is also recorded in Early Palaeozoic granitoids and metasedimentary rocks in the Mérida Andes by numerous new muscovite and biotite 40Ar/39Ar plateau dates spanning 257.1 ± 1.0 Ma to 205.1 ± 0.8 Ma. This episode of cooling is not recognised in the Santander Massif, where 40Ar/39Ar data suggest that some Early Palaeozoic rocks cooled below ~ 320 °C in the Early Palaeozoic. However, most data from pre - Jurassic rocks reveal a regional heat pulse at ~ 200 Ma during the intrusion of numerous shallow granitoids, resulting in temperatures in excess of ~ 520 °C, obscuring late Palaeozoic histories.
Article
A solicitud del Departamento de Suelos, del Instituto Geográfico de Colombia "Agustín Codazzi", se ha elaborado el croquis estratigráfico de la Sabana de Bogotá, adjunto con sus columnas correspondientes. El departamento de Fotogeología del Instituto Geológico Nacional emprenderá la obra de hacer el mapa geológico detallado de la misma zona. Aparte de la estratigrafía se caracterizan en este informe las materias útiles del suelo y subsuelo del área croquizada. Otro fin que se persigue es normalizar la nomenclatura estratigráfica. La Sabana de Bogotá es una cuenca terciaria compleja que prolonga la subsidencia cretácea del área de la cordillera Oriental al Oligoceno y, con intermitencias, al Pleistoceno y localmente al Holoceno.
Article
Durante el Meso-Cenozóico la actividad ígnea y tectónica en la cordillera Central, se desarrolla en dos etapas con caracteres distintivos. La Primera etapa, de edad Jura-Triásico, está asociada al solevantamiento de la cordillera y se manifiesta en los bordes oriental y occidental. Esta etapa consiste de intrusiones de granodiorita y cuarzomonzonita, las cuales fueron seguidas por erupciones de material félsico, principalmente de composición riodacítica. Durante el desarrollo de esta etapa la cordillera existe como un arco montañoso sometido a erosión, evidencias de este fenómeno se encuentran estudiando la composición de los clastos de las formaciones Jura-Triásicas. En el estado final se desarrolla un sistema de fallas cuya dirección predominante es NW. La Segunda etapa, la cual se denominará Ciclo Geotectónico Andino, está caracterizada por una asociación volcánico-plutónica de regiones orogénicas y se desarrolla desde el Cretáceo Inferior hasta los tiempos actuales. Cuatro fases caracterizan el Ciclo Geotectónico Andino: 1) Erupción de lavas dominantemente básicas, durante la fase geosinclinal del ciclo. Este vulcanismo inicial, típicamente de fisura, está íntimamente relacionado con el nacimiento de la falla fundamental de Romeral. 2) Inyección de plutones ultrabásicos y básicos en la zona interna del geosinclinal (intérnides) durante el estado embrionario del plegamiento. A partir de este momento la cordillera evoluciona, de área emergida, a un alto geosinclinal (Ridge) sobre el cual se depositan por primera vez sedimentos cretáceos (Aptiano) en la cordillera Central. Posteriormente se desarrolla un importante sistema de fallas, con dirección predominante NE y NW (Fallas de Otú y Palestina). 3) Desarrollo de batolitos cuarzodioríticos en la parte central de la cordillera. Como consecuencia, se origina un intenso fracturamiento y se produce reactivación y reorientación tectónica de las fallas existentes. 4) Erupciones superficiales de basaltos, andecitas y riolitas, posteriores al plegamiento pero contemporáneas al solevantamiento (Regional Uplift) final de la cordillera. Esta serie volcánica a diferencia de la primera ocurre en la zona axial de la cordillera y se manifiesta como volcanes de tipo central, los cuales empiezan a formarse durante el Mioceno. Se propone el nombre de Ciclo Geotectónico Andino, para englobar todos los fenómenos de subsidencia, vulcanismo, plutonismo, plegamiento, fracturamiento y solevantamiento que se han sucedido desde el Cretáceo Inferior hasta nuestros días y los cuales han dado origen a los Andes colombianos.
Article
Dentro de la costa noroccidental colombiana se pueden reconocer dos elementos geotectónicos principales: a) una región estable o plataforma que suprayace a una corteza continental (no plegada), y b) una región inestable o geosinclinal que suprayace a una corteza oceánica (plegada). La plataforma se ha subdividido en cuatro zonas estructurales muy prominentes: Los altos de Cicuco y El Difícil, la geofractura de Plato y la depresión tectónica de Sucre, que a su vez están controlados tectónicamente por siete lineamientos mayores del basamento con direcciones N, N20°E, N40°E, N55°W y N20°W. La región geosinclinal comprende la porción costera occidental adyacente a la plataforma, y se ha dividido en dos elementos estructurales: el cinturón fragmentado de San Jacinto de edad Eoceno medio, con una dirección N20°E y que posiblemente se extiende mucho al norte dentro del mar Caribe, y el cinturón de Sinú de edad PlioPleistoceno, paralelo al cinturón de San Jacinto hasta el área de Cartagena – Barranquilla donde toma una dirección más hacia el NE, siempre paralelo a la línea de costa. Estas formas estructurales están limitadas por tres lineamientos geomorfológicos: Romeral, Sinú y Colombia, los que considero de importancia crítica para entender la evolución tectónica y sedimentaria de esta región del Caribe colombiano. Estos tres elementos geomorfológicos, también los considero como remanentes de antiguos surcos o paleosurcos que fueron migrando sucesivamente hacia el occidente y cuyo relleno sedimentario turbidítico fue levantado y deformado progresivamente durante las orogenias pre-Andina y Andina. Así mismo, los cambios bruscos lito-faciales asociados con los márgenes de los paleosurcos, muestran una migración progresiva hacia el occidente a partir de las Iitofacies de la plataforma, a medida que aumenta el acrecimiento continental.
Article
Gravity loading of pelagic and hemipelagic sediments by denser turbidites triggered diapirism along the trench margins during the two principal accretionary episodes in the evolution of this terrane. The magnitude of deformation combined with uplift characterizes this diapirism as orogenic. The scales of deformation and uplift also appear directly related to the intensity of turbidite sedimentation. Each episode of intense diapirism was followed by uplift accompanied by little deformation. The diapirism appears related to deep-sea sedimentation, whereas uplift was accompanied by shallower marine and terrestrial sedimentation. -from Author
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Detrital modes of sandstone suites primarily reflect the different tectonic settings of provenance terranes, although various other sedimentological factors also influence sandstone compositions. Comparisons of sandstone compositions are aided by grouping diverse grain types into a few operational categories having broad genetic significance. Compositional fields associated with different provenances can then be displayed on standard triangular diagrams. The major provenance types related to continental sources are stable cratons, basement uplifts, magmatic arcs, and recycled orogens. Each provenance type contributes distinctive detritus preferentially to associated sedimentary basins that occupy a limited number of characteristic tectonic settings in each case. Sands of composite provenance can be described as mixtures of quartzose sand from stable cratons, quartzofeldspathic sand from basement uplifts or arc plutons, feldspatholithic sand from arc volcanics, and quartzolithic sands of several types from different kinds of recycled orogens that yield varying proportions of quartzose and lithic grains. Proportions of contributions from different provenance types can be estimated from mean compositions for ideal derivative sands represented by points or restricted areas on triangular plots. Evolutionary trends in sandstone composition within individual basins or sedimentary provinces commonly reflect changes in tectonic setting through time, or erosional modification of provenance terranes. Forearc sandstone suites typically evolve from feldspatholitic petrofacies of volcaniclastic nature, through lithofeldspathic petrofacies of volcanoplutonic origin, to quartzofeldspathic petrofacies of plutonic derivation. Foreland sandstone suites commonly evolve from rift-related quartzofeldspathic petrofacies, through quartzose petrofacies of passive continental margins, to quartzolithic petrofacies derived from recycled orogens.
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Forearc basins are large sediment repositories that develop in the upper plate of convergent margins and are a direct response to subduction. These basins are part of the magmatic arc-forearc basin-accretionary prism “trinity” that defines the tectonic configuration of the upper plate along most subduction-related convergent margins. Many previous studies of forearc basins have explored the links between construction of magmatic arcs, exhumation of accretionary prisms, and sediment deposition in adjacent forearc basins. These studies provide an important framework for understanding firstorder tectonic processes recorded in forearc basins that are characterized by long-lived subduction of “normal” oceanic crust. Many convergent margins, however, are complicated by second-order subduction processes, such as flat-slab subduction of buoyant oceanic crust in the form of seamounts, spreading and aseismic ridges, and oceanic plateaus. These second-order processes can substantially modify the tectonic configuration of the upper plate both in time and space, and produce sedimentary basins that do not easily fit into the conventional magmatic arc-forearc basin-accretionary prism trinity.