Conference PaperPDF Available

FANGOLITAS BITUMINOSAS ASOCIADAS A FLUJOS FLUIDOS DE FANGO, FORMACIÓN VACA MUERTA (TITHONIANO -VALANGINIANO), CUENCA NEUQUINA, ARGENTINA

Conference Paper

FANGOLITAS BITUMINOSAS ASOCIADAS A FLUJOS FLUIDOS DE FANGO, FORMACIÓN VACA MUERTA (TITHONIANO -VALANGINIANO), CUENCA NEUQUINA, ARGENTINA

XVI
RAS
26 al 30 de noviembre de 2018
General Roca - Río Negro
LIBRO DE RESÚMENES
XVI REUNIÓN ARGENTINA DE SEDIMENTOLOGÍA 2018
LIBRO DE RESÚMENES
ORGANIZAN
AUSPICIAN
Libro de Resúmenes de la XVI Reunión Argentina de Sedimentología:
Sedimentología Sin Frontera. 26 al 30 de noviembre de 2018. General Roca,
Río Negro, Argentina.
Edición: Alejandro David Báez y Ricardo Gómez
Diseño Visual: Julio Bariani y Manuela Zalazar
XVI REUNIÓN ARGENTINA DE SEDIMENTOLOGÍA 2018
LIBRO DE RESÚMENES
COMITÉ ORGANIZADOR
Presidente
Juan José Ponce (CONICET-UNRN)
Vice-Presidente
Aldo Omar Montagna (YPF-UNRN)
Secretaria
Nerina Canale (CONICET-UNRN)
Tesorera
Débora Mical Campetella (CONICET-UNRN)
Vocales
Noelia Beatriz Carmona (CONICET-UNRN)
Alberto Tomás Caselli (CONICET-UNRN)
Emiliano Santiago (YPF)
Silvio Casadío (CONICET-UNRN)
Fabián Gutiérrez (YPF)
Josefina Pons (CONICET-UNRN)
Martín Cevallos (CGC-UNSJ)
Nayibe Otalora Ardila (YPF)
Julieta Omarini (CONICET-UNRN)
Manuela Zalazar (CONICET/YTEC-UNRN)
Alejandro David ez (CONICET-UNRN)
Ricardo Gómez (AGENCIA-UNRN)
Maximiliano Nicolás Rodríguez (CONICET-UNRN)
XVI REUNIÓN ARGENTINA DE SEDIMENTOLOGÍA 2018
LIBRO DE RESÚMENES
COMITÉ CIENTÍFICO
Cecilia Eugenia del Papa (CONICET-CICTERRA)
Eduardo Luis Piovano (CONICET-CICTERRA)
Gastón Matías Iovine Palafox (YPF)
Matías Miguel Salvarredy Aranguren (YPF-UNPSJB)
Marcelo Krause (CONICET-MEF)
Eduardo Sergio Bellosi (CONICET-MACNBR)
Pablo Bouza (CONICET-CENPAT).
Carlos Alberto Zavala (GCS-UNS)
Ricardo Gómez Omil (WINTERSHALL)
Juan José Ponce (CONICET-UNRN)
Carlos Oscar Limarino (IGEBA)
Ezequiel González (YTEC)
Maisa Andrea Tunik (CONICET-UNRN)
Alberto Tomás Caselli (CONICET-UNRN)
Walter Baez (CONICET-INENCO)
Romina Daga (CONICET-CNEA)
Mario Schiuma (YPF S.A.)
Ernesto Schwarz (CONICET-CIG)
Silvia Marcomini (IGEBA)
Carlos Echevarria (PAMPAENERGÍA)
Gonzalo Diego Veiga (CONICET-CIG)
Alfonsina Tripaldi (CONICET-IGEBA)
Agustín Arguello Scotti (YPF. S.A.)
José Oscar Allard (UNPSJB)
Nicolás Foix (CONICET-UNPSJB)
Jorge Hechem (YPF)
Carlos Daniel Arregui (PAMPA ENERGIA-UNCOMA)
Diana Cuadrado (CONICET-IADO)
Miguel de Moraes Lima Silveira (Petrobras S.A.)
Ivan Lanusse (YPF)
Guillermina Sagasti (YPF)
Silvio Casadío (CONICET-UNRN)
María Angélica Diez (UNRN)
Leandro D’elía (CONICET-CIG)
175
XVI REUNIÓN ARGENTINA DE SEDIMENTOLOGÍA 2018
T-S11: SISTEMAS NO CONVENCIONALES
FANGOLITAS BITUMINOSAS ASOCIADAS A FLUJOS
FLUIDOS DE FANGO, FORMACIÓN VACA MUERTA
(TITHONIANO -VALANGINIANO), CUENCA NEUQUINA,
ARGENTINA
Germán Aníbal Otharán1,2,3, Carlos Alberto Zavala2,3, Mariano Arcuri2,3,
Mariano Di Meglio2,3, Agustín Zorzano2,3, Denis Marchal4 y Guillermina
Köhler4
1 CONICET
2 GCS Argentina SRL. Interna 1320, Bahía Blanca, 8000, Buenos Aires, Argentina
3 Departamento de Geología, Universidad Nacional del Sur. Av. Alem 1253, cuerpo B´ - 2º Piso, Bahía
Blanca, 8000, Argentina
4 Pampa Energía S.A. Maipú 1, CABA
gotharan@gcsargentina.com
Se presenta un estudio sedimentológico de afloramiento y subsuelo de la
Formación Vaca Muerta en áreas centrales de la Cuenca Neuquina. El estudio
de afloramiento estuvo enfocado al análisis puntual de cortes macroscópicos
pulidos de concreciones carbonáticas, las cuales preservan un registro
excepcional de los rasgos sedimentarios primarios presentes en depósitos
fangolíticos. El estudio de subsuelo permitió desarrollar un análisis
sedimentológico continuo de diferentes testigos corona de la Formación Vaca
Muerta. Los resultados obtenidos sugieren que existe una gran variedad de
depósitos de grano fino (<62,5) acumulados a partir de flujos fluidos de fango
de distinta naturaleza. Su origen parece estar relacionado a dos procesos
principales: flujos hiperpícnicos fangosos de larga duración (origen
extracuencal) y flujos de fango intracuencales asociados a procesos de
resedimentación. Los flujos de fango intracuencales serían más frecuentes en
sectores próximos al quiebre de la plataforma, generando depósitos con bajo
contenido orgánico. Por otro lado, los flujos hiperpícnicos fangosos de origen
extracuencal habrían actuado como excelentes medios de transferencia de
sedimentos finos y materia orgánica desde áreas emergidas hasta zonas
internas de la cuenca, atravesando relieves de muy baja pendiente. En su
trayectoria cuenca adentro, habrían incorporado material intracuencal
previamente depositado creando depósitos mixtos. La rápida transferencia de
fango rico en materia orgánica (tipo II y III) hacia sectores internos de la cuenca
habría permitido alcanzar un soterramiento rápido y eficiente, evitando su
exposición en el fondo marino. Este proceso habría favorecido la preservación
de fangos bituminosos en sectores internos de la Cuenca Neuquina.
... El hecho de que esta facies exhiba una diferencia composicional tan marcada entre láminas de fangolitas gruesas detríticas y fangolitas arenosas intraclásticas parece estar asociado a un fenómeno de competencia hidráulica entre las partículas. Se interpreta que el origen de las variaciones rítmicas en el tamaño del grano común a la facies FsL podría estar asociado a flujos de larga duración sujetos a ligeras fluctuaciones en su velocidad y concentración sedimentaria (Otharán y Zavala, 2018;Otharán et al., 2018b). ...
Article
Full-text available
The conventional sedimentological model suggests that the accumulation of organic-rich fine-grained sedimentary rocks (<62.5 μm) is uniquely associated with fallout processes in low energy depositional environments. This contribution analyzes organic-rich mudstones belonging to the lower section of the Vaca Muerta Formation at central areas of the Neuquén Basin (Arroyo Mulichinco, Tres Chorros and Río Neuquén localities). The studied interval is characterized by the highest organic matter content of the Vaca Muerta Formation (up to 8% TOC). The associated mudstone deposits are usually highly compacted, thus obscuring the recognition of the original fabric and the analysis of mudstone depositional processes. Nevertheless, the common occurrence of carbonate concretions within these highly compacted intervals provides an exceptional preservation of mudstone primary fabric. After macroscopic study of polished slabs and thin sections of these cemented beds, a series of facies genetically linked to muddy underflows were recognized. The origin of these deposits is related to long-lived muddy hyperpycnal flows (quasi-steady mud flows) triggered by extreme river discharges during rainfall humid periods. During their travel basinward, hyperpycnal flows, originally composed of detrital mud, would be able to go through very low gradient reliefs, incorporating the available intrabasinal components (including organic matter) to their extrabasinal sedimentary load. The rapid basinward transfer of organic-rich mud would have provided a fast deposition and efficient burial of organic matter, avoiding its potential degradation at seafloor. Muddy underflows constitute a rational mechanism to explain the common occurrence of bituminous mudstones at central areas of the Neuquén Basin.
Article
This paper presents a multidisciplinary study of a new basinal section of Tithonian-Berriasian the Vaca Muerta Formation at Las Tapaderas area, including detailed, biostratigraphic, sedimentologic, sequence stratigraphic and cyclostratigraphic analysis. Biostratigraphy based on ammonite, calpionellids and calcareous dinoflagellate cysts indicate that Las Tapaderas section spans through the Lower Tithonian - lowermost Upper Berriasian, however, its upper part is covered through an erosive unconformity by Pleistocene volcaniclastic deposits, and therefore Las Tapaderas section could reach the Lower Valanginian. Two facies associations were identified, corresponding to basinal and distal outer ramp subenvironments. Recognition of flooding surfaces allowed the identification of three composite depositional sequences and eight high-frequency depositional sequences, which can be correlated with other sections throughout the basin. Cyclostratigraphic analysis based on the recognition of marlstone/limestone couples (elementary cycles) allowed to build a time series based on bed thickness. Fourier analysis indicates the characteristic mid latitude precession-eccentricity syndrome, with 220 precessional cycles (∼20.4 and ∼23 kyr), 53 low frequency eccentricity cycles (∼79, ∼90 and ∼140 kyr) and 11 high frequency eccentricity cycles (∼400 kyr). Spectral analysis also allowed to recognize the presence of the obliquity cycle (38.5 kyr), which has been erratically recorded in the Vaca Muerta Formation. Our data allowed the construction of an orbital scale, calibrated by cosmopolitan markers (calpionellids and calcareous dinoflagellate cysts), for this section. The precise bio- and cyclostratigraphic location of the Jurassic-Cretaceous boundary was established for this section. The sedimentation rate was studied at the scale of the precession cycle, showing values between 0.6 and 3 cm/kyr, while at the low-frequency eccentricity scale it shows values between 1 and 2 cm/kyr.
Article
The Vaca Muerta-Quintuco (VM-Q) system of Tithonian-early Valanginian age was studied in the Chacay Melehue section of the Neuqu´en Basin (western Argentina) by means of sedimentological, mineralogical and geochemical analyses in order to determine the main driving factors that triggered the paleoenvironmental change from a carbonate ramp (Vaca Muerta Formation, VMFm) to a mixed siliciclastic/carbonatic marine environment (Quintuco Formation, QFm). The VMFm was divided into two stratigraphic intervals: Lower VMFm (LVMFm) and Upper VMFm (UVMFm), whereas the QFm is subdivided into the Puesto Barros Member (PBMb) and the Cerro La Visera Member (CVMb), which can be correlated to other sections in the basin (e.g., Puerta Curaco). Isolated, turbiditic sandstone beds, correlated to the Huncal Member, are included in the QFm. The LVMFm (Tithonian) and the UVMFm (Berriasian) are constituted by dark, well-laminated marls, mudstones, calcite concretions and tuffs. The PBMb (earlier early Valanginian) is constituted by marls and sandstones, whereas the CVMb (later early Valanginian) is constituted by marls, mudstones, siltstones, sandstones and coquinas. The LVMFm (Total organic carbon, TOC ~ 1–4 wt%) is characterized by the enrichment of redox sensitive trace elements (RSTE), where the enrichment of Ni and Cu suggest high productivity in the water column, and the enrichment of Mo, U, V points to sea bottom anoxia, with periods of increased oxygenation as deduced from higher P concentrations in marls and mudstones. The clay mineral association is constituted by mixed-layer illite/smectite formed by the transformation of smectitic layers. The predominance of smectite in coeval sucessions, less overprinted by burial diagenesis, suggests a temperate and semi-arid climate in the adjacent continent. The UVMFm (TOC ~ >1 wt%) is characterized by a gradual decrease of the RSTE pointing to a decrease in productivity and a slight increase in the oxygenation of the sea bottom. In addition, a change towards more humid conditions in the continent is inferred by both the increase in the Chemical Index of Alteration and the Al2O3/TiO2 ratio. The PBMb (TOC ~1 wt%) has even lower content of RSTE indicating diminished sea water productivity and a gradual rise of the oxygenation of the sea bottom. In this interval, increased illite contents suggest periods of enhanced physical weathering, probably related to the tectonic uplift of the Huincul Ridge. The RSTE in the CVMb (TOC <1 wt%) documents a fully oxygenated sea bottom, where the productivity of the water column was negligible. The presence of kaolinite and the increment of the detrital sedimentation in the CVMb indicate a change towards more humid conditions in the hinterlands. The enhanced runoff caused by this paleoclimatic change towards more humid conditions that started in the early Berriasian and increased during the later early Valanginian triggered the change from carbonate ramp to mixed siliciclastic/carbonatic to siliciclastic marine paleoenvironments. The organic carbon isotope composition (δ13Corg vs. VPDB) of the VMFm ranges between - 30.0 and - 23.4‰, whereas in the QFm values range between - 29.0 and - 23.9‰. Two positive carbon isotope excursions (PCIE) are recorded in the system: PCIE-A in the lower part of the VMFm (early Tithonian) with δ13Corg values ~ - 25‰, and PCIE-B in the upper part of the QFm (later early Valanginian) with δ13Corg values ~ - 24.5‰. The shift in δ13Corg at PCIE-B is up to +4.2‰ and marks the onset of the Weissert Event. This is the first time that the onset of this event is recorded in the Neuqu´en Basin, within the Lissonia riveroi ammonite zone. The results of our study confirm that clay mineralogy, trace elements and stable isotopes are valuable proxies of past ocean-climate variability even in sediment deposits that underwent nearsurface and deep burial diagenesis.
Article
Full-text available
A hyperpycnal flow forms when a relatively dense land-derived gravity flow enters into a marine or lacustrine water reservoir. As a consequence of its excess of density, the incoming flow plunges in coastal areas, generating a highly dynamic and often long-lived dense underflow. Depending on the characteristics of the parent flow (flow duration and flow rheology) and basin salinity, the resulting deposits (hyperpycnites) can be very variable. According to flow duration, land-derived gravity flows can be classified into short-lived or long-lived flows. Short-lived gravity flows last for minutes or hours, and are mostly related to small mountainous river discharges, alluvial fans, collapse of natural dams, landslides, volcanic eruptions, jökulhlaups, etc. Long-lived gravity flows last for days, weeks or even months, and are mostly associated with medium- to large-size river discharges. Concerning the rheology of the incoming flow, hyperpycnal flows can be initiated by non-Newtonian (cohesive debris flows), Newtonian supercritical (lahars, hyperconcentrated flows, and concentrated flows) or Newtonian subcritical flows (pebbly, sandy or muddy sediment-laden turbulent flows). Once plunged, non-Newtonian and Newtonian supercritical flows require steep slopes to accelerate, allow the incorporation of ambient water and develop flow transformations in order to evolve into a turbidity current and travel further basinward. Their resulting deposits are difficult to differentiate from those related to intrabasinal turbidites. On the contrary, long-lived Newtonian subcritical flows are capable of transferring huge volumes of sediment, freshwater and organic matter far from the coast even along gentle or flat slopes. In marine settings, the buoyant effect of interstitial freshwater in pebbly and sandy hyperpycnal flows can result in lofting due to flow density reversal. Since the excess of density in muddy hyperpycnal flows is provided by silt-clay sediments in turbulent suspension, lofting is not possible even in marine/saline basins. Muddy hyperpycnal flows can also erode the basin bottom during their travel basinward, allowing the incorporation and transfer of intrabasinal sediments and organic matter. Long-lived hyperpycnal flow deposits exhibit typical characteristics that allow a clear differentiation respect to those related to intrabasinal turbidites. Main features include (1) composite beds with gradual and recurrent changes in sediment grain-size and sedimentary structures, (2) mixture of extrabasinal and intrabasinal components, (3) internal and discontinuous erosional surfaces, and (4) lofting rhythmites in marine/saline basins.
ResearchGate has not been able to resolve any references for this publication.