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Sediment generation and provenance: process and pathways - Editorial

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The ability to trace sediments from their sources to sedimentary basins is a prerequisite for quantitative analysis of Earth-surface dynamics. The comparatively recent revival of sedimentary provenance analysis goes hand-in-hand with the ever expanding range of analytical tools available for quantifying sediment properties (isotopic, mineral, chemical, and petrographic composition, grain-size and shape distributions, age spectra, etc.), and for interpreting such data in paleo-geographic, -tectonic and -climatic terms. The breakdown of sediment budgets into source-specific contributions - one of the most important tasks of provenance analysis - permits quantification of rates of surface processes in the geological past ("deep time"), even in cases where the source areas themselves have been destroyed by global tectonics. Quantitative sedimentary provenance analysis is therefore crucial to the reconstruction of ancient sediment-routing systems, the fundamental units of mass transfer at the Earth's surface. This special issue of Sedimentary Geology results from the 2nd meeting of the Working Group on Sediment Generation (WGSG), held in June 2014 at the Georg-August University of Göttingen, Germany. The meeting hosted scientists from a broad range of disciplines and included, besides diverse topics related to provenance analysis and data treatment, contributions focused on detrital geochronology, sediment budgets and applied geomorphology. The meeting recorded the growth of the WGSG group with new participants from academic institutions including Trinity College Dublin, Darmstadt Technical University, Bern University, University College London, University of Münster and industrial partners such as Chemostrat Ltd. During the meeting, objectives for future research were defined, including the understanding and quantification of (i) the effects of sediment recycling in the geological record, (ii) mechanical weathering, i.e. the selective breakdown of particles, and (iii) chemical weathering. The special issue presents a selection of contributions to the 2nd WGSG meeting. It opens with a critical review of models currently used in provenance analysis of sands and sandstones by Eduardo Garzanti, who shows that the relationship between sediment composition and geodynamic setting is far from univocal. He proposes a new descriptive classification scheme to be used as a starting point for an upgraded dynamic approach to sedimentary petrology focusing on the nature and tectono-stratigraphic level of source terranes. The fundamental information obtained by petrographic investigation of rock fragments is emphasized. The second section concentrates on analytical methods and tests of provenance approaches. Pieter Veermesch and co-authors present provenance, a software package within the well-known open-source statistical programming environment “R” that aims to facilitate the visualisation and interpretation of large amounts of sedimentary provenance data, including mineralogical, petrographic, chemical and isotopic proxies. The package provides a number of functions tools and will be regularly expanded based on user feedback. Abijit Basu and co-authors test the applicability of chemical composition of siliciclastic rocks to infer their provenance and tectonic setting. The authors validate some of the indications given by traditional diagrams, but more importantly, they discuss the factors that may complicate interpretation. Christiane Scholonek and Carita Augustsson focus on the use of cathodoluminescence for extracting provenance information from feldspar grains. Their results, obtained from the measurement of a great number of feldspar crystals contained in both igneous and metamorphic rocks, support the usefulness of this technique in provenance studies. The third section includes case studies on modern sediments. Fabio Scarciglia and co-authors integrate macro- and micromorphological observations with physico-mechanical field tests and petrographic, mineralogical and geochemical analyses to constrain the first step of sediment generation and quantify soil production and erosion rates of weathering profiles on granitoid rocks of the Sila Massif in southern Italy. Hilmar von Eynatten and co-authors investigate sediments generated from plutonic bedrocks exposed to humid-temperate Mediterranean climate. Geochemical data of several grain size fractions from coarse sand to clay are coupled to mineralogical data obtained by X-ray diffraction and Mineral Liberation Analysis (MLA). By means of linear regression modeling of geochemistry vs. grain-size variability the authors relate compositional changes to sediment formation processes. Eduardo Garzanti and Alberto Resentini question the use of classical chemical indices (e.g., CIA, WIP, α values) to infer weathering and paleo-weathering conditions in source areas. In their modern case study of sediments generated in Taiwan, where even in wet-tropical climate physical erosion prevails because of extreme tectonic-uplift rates, chemical parameters are documented to depend chiefly on provenance rather than on weathering. Sandra Schneider and co-authors investigate the effects of chemical weathering on sands and muds generated in equatorial Africa, the factors controlling weathering rates, and the extent and conditions under which original provenance signatures are preserved. In the extreme case of the rift-related Rwenzori basement uplift, they document how daughter sediments may faithfully reflect parent lithologies even in wet equatorial climate. Anne Krippner and co-authors use heavy-mineral analysis and geochemistry of garnets in bedrocks and stream sediments derived from the Almklovdalen peridotite massif in SW Norway to test the representativeness of provenance signals provided by these methods. The results underline the high potential of both methods in reconstructing sediment provenance if (i) sampling sites in the drainage system are carefully selected and (ii) a relatively wide grain-size spectrum is considered to avoid misleading interpretations. The fourth section includes contributions on volcaniclastic sedimentation and dispersal mechanisms. Luca Caracciolo and co-authors focus on chemical fingerprints of detrital amphibole and pyroxene to reconstruct the dispersal mechanisms of volcanic material recorded in the Tertiary volcaniclastic sediments of the northwestern Thrace basin. Single-grain compositional signatures are used to discriminate provenance from the numerous volcanic centres active at the time of deposition. Kathleen Marsaglia and co-authors study proximal arc-derived Cretaceous sediments deposited in a volcano-bounded shallow-marine basin and in a fault-bounded deep-marine basin to evaluate the role of depositional processes on sediment detrital modes. They demonstrate that both differences in basin type and mechanisms of deposition have limited effects on sediment composition when sedimentation is controlled by a single major subaerial volcanic edifice. Andrea Di Capua and co-authors integrate sedimentological analysis with conglomerate clast counting and petrographic analyses to determine the influence of climate, tectonic activity and volcanism on sediment supply in the Oligocene foredeep of the northern Appenines. Their results indicate strong control by the activation of deformational fronts during syn- and post-eruptive periods. The 5th and last section present a series of assorted provenance case studies. Heinrich Bahlburg and Jasper Berndt analyse detrital zircons from the Devonian and Upper Paleozic siliciclastic rocks of northern Chile. Their results would point to provenance from the Faja Eruptiva, a Ordovician calc-alkaline intrusive belt in NW Argentina, which is in clear disagreement with mass-balance calculation and paleocurrent data. The authors show how the misleading provenance indications provided by detrital-zircon geochronology can be ascribed to the effects of assimilation of and contamination of magma by crustal igneous, metamorphic and sedimentary rocks during its evolution and ascent. Pedro Dinis and Álvaro Oliveira use X-ray diffraction and bulk-rock geochemistry to reconstruct the provenance of recycled Pliocene clays in western Iberia (Portugal) and evaluate the mineralogical transformation occurred during the last depositional cycle. They also consider different grain-size windows and conclude that REE still preserve the original provenance signal, whereas major elements reflect different degrees of chemical weathering in different parent lithologies. Udo Zimmermann and co-authors adopt a comprehensive analytical approach to characterise the composition and provenance of 5th-6th century pottery material from southwestern Norway. The combination of bulk-rock geochemistry EDS, XRD and Raman spectroscopy reveals the provenance of the material studied, pointing to the Karmøy region as the place of origin. The final contribution to this special issue represents one of the many potential applications of provenance analysis outside of the field of sedimentary geology.

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... Modelling the composition is more complicated than one might expect given the number of parameters that determine the occurrence and distribution of primary and secondary mineral phases in sediments. The factors controlling the composition of clastic sediments, and associated biases, have been extensively studied in the past and included in landmark special volumes (Johnsson and Basu, 1993;Valloni and Basu, 2003;von Eynatten et al., 2012a;Caracciolo et al., 2016a;Weltje et al., 2018) and reviews from Suttner (1974), Basu (1985aBasu ( , 1985b, Pettijohn et al. (1987), Haughton et al. (1991), Johnsson (1993), McLennan et al. (1993), Cox and Lowe (1995), Morton and Hallsworth (1999), Weltje (2002), Basu and Valloni (2003), Weltje and von Eynatten (2004), Najman (2006), Garzanti et al. (2007a,b), (Garzanti, 2019). Despite the fact that the role of tectonics, climate, lithology, transport dynamics and post-burial modifications ( Fig. 1) are relatively well understood, the connection between modern systems and deep-time stratigraphy remains significantly underdeveloped. ...
... When coupled together, sedimentary petrography and single-grain analysis can precisely identify the origin of volcanic material and attribute them to specific volcanic eruptions and provide key information for paleogeographic and paleodrainage reconstruction (e.g. Caracciolo et al., 2016a). Supercontinent cycles with timescales of 10 6 to 10 8-9 years can be successfully restored through the integration of most of the techniques described above (Fig. 8), especially when integrated with regional geology and other constraints such as complementary isotopic analyses on single grains (e.g. ...
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... The WGSG (www.wgsg.info) is an informal group bringing together Earth scientists broadly interested in expanding the knowledge of sediment generation and provenance in research and teaching. The WGSG has held multiple training schools for early career researchers and has published four special issues since its foundation in 2009 (Caracciolo et al., 2016von Eynatten et al., 2012;Weltje et al., 2018). ...
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Clastic sediment composition constitutes a key archive of Earth history, controlled by allogenic and autogenic processes that impact weathering, erosion, sediment transfer, and deposition. Deciphering those processes can provide valuable insights into ancient and modern tectonic, geomorphic, climatic, and anthropogenic controls that shape sediment routing systems over a wide range of temporal and spatial scales. However, in order to clearly identify the controls on sediment composition, it is necessary to exclude sources of bias that may mask or diminish the original provenance signal. Such biases may be natural, including mineral fertility, sediment recycling, and grain size, or analytical. This special collection arises from the fifth meeting of the working group on sediment generation held at the University Milano‐Bicocca in Milan, Italy, from 28 to 30 June 2022. The collation includes studies that investigate biasing factors affecting all steps of the sediment cascade and all stages of sample collection, preparation, and analysis, as well as case studies that aim to disentangle original provenance signals from geological, environmental, or analytical noise.
... The sedimentary record of a foreland basin offers the opportunity to study the interplay between distinct source areas, allowing to infer the uplift and exhumation history of mountain belts [1][2][3]. Sediment provenance analysis is a useful tool to understand the processes occurring in the hinterland of a sedimentary basin and enables to constrain the timing of geodynamic events, as well as to unravel sediment pathways and correlate stratigraphic sequences [4][5][6][7][8][9][10]. This arduous task requires combining as many provenance indicators as possible in order to achieve the highest resolution for identifying and characterizing the sediment routing systems in the related basins [8,[11][12][13][14][15]. Sandstone petrography and heavy mineral analysis are widespread techniques in sedimentary provenance studies [5,8,[16][17][18][19][20][21][22]. ...
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Combined sandstone petrography and heavy mineral analysis allow to decipher different sediment routing systems that could not be resolved by one method alone in the South Pyrenean foreland basin. We apply this approach to deltaic and alluvial deposits of the southern part of the Jaca basin, and in the time equivalent systems of the nearby Ainsa and Ebro basins, in order to unravel the evolution of source areas and the fluvial drainage from the Eocene to the Miocene. Our study allows the identification of four petrofacies and five heavy-mineral suites, which evidence the interplay of distinct routing systems, controlled by the emergence of tectonic structures. Two distinct axially-fed systems from the east coexisted in the fluvial Campodarbe Formation of the southern Jaca basin that were progressively replaced from east to west by transverse-fed systems sourced from northern source areas. In the late stages of evolution, the Ebro autochthonous basin and the Jaca piggy-back basin received detritus from source areas directly north of the basin from the Axial Zone and from the Basque Pyrenees. Coupling sandstone petrography with heavy mineral provenance analysis allows challenging the existing model of the South Pyrenean sediment dispersal, highlighting the relevance of this approach in source-to-sink studies. Keywords: provenance; sandstone petrography; heavy minerals; sediment routing systems; Jaca basin; South Pyrenean foreland; Pyrenees
... Among these, the identification of both tectonic and climatic perturbations represents one challenge. External forcing controls can be identified and quantified using quantitative provenance analysis (QPA - Weltje and von Eynatten, 2004;Garzanti et al., 2014;Caracciolo et al., 2015Caracciolo et al., , 2016 or by applying empirical scaling relationships and numerical models based on modern analogues (Sømme et al., 2009;Allen, 2017;Nyberg et al., 2018). Sediment discharge (Q) currently is the most frequently used parameter to document paleo-sediment fluxes induced by external perturbations, despite the difficulty to predict it with high accuracy in ancient systems (Allen et al., 2013b;Covault et al., 2013;Caracciolo, 2020). ...
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Reconstructing sediment load in deep-time is one of the greatest challenges in the reconstruction of ancient sediment routing systems, particularly because solid statistical models are absent and paleo-climatic, paleo-tectonic, and sedimentary constraints are lacking. This study proposes a reliable workflow for the estimation of paleo-sediment fluxes (Qs) applying the BQART model to a case study from the SE Germanic Basin across the Middle Permian – Early Triassic interval. The input parameters of the simulations derive from: integrated plate modelling and structural kinematics; paleodrainage and paleogeographic reconstructions; global circulation models; and sandstone compositional signatures. We apply Monte Carlo simulation to overcome the input uncertainties for eight different scenarios obtained from the combination of two area estimates, two climate models, and two time resolutions. All the models are in general agreement and show changes in sediment flux (i) being steady or declining slightly through the Middle Permian, (ii) an increase of 31% at the beginning of the Late Permian (3.6–4.6 Mt yr−1), (iii) and a nearly 100% rise at the onset of the Early Triassic (7.4 Mt yr−1). The variation of sediment load across the PTB is coeval to the transition from meandering/sabkha to perennial braided depositional settings recorded from the well data of Obernsees-1 and Lindau-1; it results from both increased tectonism and seasonal precipitation. The Qs estimates agree with those of modern drainages under analogous environmental conditions, highlighting the reliability of the workflow included in this study for the quantification of sediment flux in deep time. Furthermore, the results of this study provide new insights on the highly debated evolution of the continental sequences across the PTB with strong implications for both past and future paleo-environmental reconstructions.
... The sedimentary infill of a foreland basin may record the interaction of distinct source areas, thus offering a good opportunity to study the interplay between them and to infer the evolution of the uplift and exhumation of mountain belts (e.g., Dickinson and Suczek 1979;Steidtmann and Schmitt 1988). Sediment provenance studies are important to understand the processes occurring in the hinterland of a sedimentary basin, helping to constrain the timing of geodynamic events, to unravel sediment pathways, and to correlate stratigraphic sequences (Graham et al. 1986;Haughton et al. 1991;Mange-Rajetzky 1995;Von Eynatten and Dunkl 2012;Garzanti et al. 2013aGarzanti et al. , 2013bKilhams et al. 2014;Caracciolo et al. 2016). In complex geodynamic settings, the integration of as many provenance tools as possible is essential to resolve ambiguous provenance signals when facing sediment routing in related basins (Dickinson 1988;Nie et al. 2012;Garzanti et al. 2013a;Garzanti 2016;Caracciolo et al. 2019;McKellar et al. 2020). ...
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In the Jaca foreland basin (southern Pyrenees), two main sediment routing systems merge from the late Eocene to the early Miocene, providing an excellent example of interaction of different source areas with distinct petrographic signatures. An axially drained fluvial system, with its source area located in the eastern Central Pyrenees, is progressively replaced by a transverse-drained system that leads to the recycling of the older turbiditic foredeep. Aiming to provide new insights into the source-area evolution of the Jaca foreland basin, we provide new data on heavy-mineral suites, from the turbiditic underfilled stage to the youngest alluvial-fan systems of the Jaca basin, and integrate the heavy-mineral signatures with available sandstone petrography. Our results show a dominance of the ultrastable Ap-Zrn-Tur-Rt assemblage through the entire basin evolution. However, a late alluvial sedimentation stage brings an increase in other more unstable heavy minerals, pointing to specific source areas belonging to the Axial and the North Pyrenean Zone and providing new insights into the response of the heavy-mineral suites to sediment recycling. Furthermore, we assess the degree of diagenetic overprint vs. provenance signals and infer that the loss of unstable heavy minerals due intrastratal dissolution is negligible at least in the Peña Oroel and San Juan de la Peña sections. Finally, we provide new evidence to the idea that during the late Eocene the water divide of the transverse drainage system was located in the North Pyrenean Zone, and areas constituted by the Paleozoic basement were exposed in the west-Central Pyrenees at that time. Our findings provide new insights into the heavy-mineral response in recycled foreland basins adjacent to fold-and-thrust belts.
... Mineralogical, geochronological and thermochronological analyses were undertaken on selected sediments from cutting samples derived from borehole K14-12 ( Fig. 3; material provided by Nederlandse Aardoile Maatschappij (NAM)). Previous work demonstrates that provenance analysis is an accurate method for the identification of the source areas of sediment in glacial environments and in the SNS region (Zandstra 1983;Morton & Hallsworth 1994;Kuhlmann et al. 2004;Weltje & von Eynatten 2004;Sch€ uttenhelm & Laban 2005;Krippner & Bahlburg 2013;Caracciolo et al. 2016;Hodder et al. 2016). Due to the high degree of dilution of compositional signals that occurs during whole-rock analysis, datawere complemented with single-mineral analysis. ...
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This study offers new insights into the origin and depositional history of the mixture of sediments infilling one of the largest offshore, northward-orientated, clinoform-structured, tunnel valleys (TVs) of Elsterian age in the southern North Sea (SNS). Specifically, the study sheds light on the provenance of TV deposits based on K-Ar dating of illite, QEMSCAN� heavy mineral assemblage study, and U-Pb and fission track dating on single grains of apatite. Early Pleistocene substrate and the TV infill demonstrate provenance from the Scandinavian and Baltic realms as well as from Renish central Europe and the Alps. Prior to Elsterian glaciation fluvial transport to the SNS increasingly switched from Baltic sources to a more central European influence. However, based on similar provenance of both the substrate and TV infill, the episode of subglacial tunnel valley formation interrupted this central European influence. Glacial erosional processes associatedwith the expansion of theElsterianice sheet to the SNS reworked alarge amount of sediment from theEarly Pleistocene deposits of the SNS. The sediment was eventually deposited as the tunnel valley infill. Taking into account a high uncertainty related to the facies of TV sedimentary infill, which thus far has been inferred from seismic reflection surveys only, this study offers the first comprehensive set of data on the composition and provenance of the offshore Elsterian TV sediment.
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We here review what is known about the dunefields and fluvial systems of the Kalahari Basin in terms of geological setting and Quaternary dynamics and set out what has been hypothesized about the provenance of Kalahari sand so far. Previous work has tackled this problem by applying a limited number of techniques (mostly sediment textures and heavy minerals) to parts of the large dryland. The generally highly quartzose mineralogy of aeolian dunes and their compositional variability have been only broadly evaluated and several sedimentological issues have thus remained controversial, including the relative role played by fluvial processes versus aeolian reworking of older sediments and weathering controls. This reveals a need for a systematic provenance study that considers the entire basin. For this reason, here we combine original petrographic, heavy-mineral, and detrital-zircon geochronology data with previously published clay-mineral, geochemical, and geochronological information to present the first comprehensive provenance study of the vast Kalahari sand sea. Our multi-proxy dataset comprises 100 samples, collected across the Kalahari Basin from 11°S (NW Zambia) to 28°S (NW South Africa) and from 15°E (Angola) to 28°30′W (Zimbabwe). Kalahari aeolian-dune sand mostly consists of monocrystalline quartz associated with durable heavy minerals and thus drastically differs from coastal dunefields of Namibia and Angola, which are notably richer in feldspar, lithic grains, and chemically labile clinopyroxene. The western Kalahari dunefield of southeastern Namibia is distinguished by its quartz-rich feldspatho-quartzose sand, indicating partly first-cycle provenance from the Damara Belt and Mesoproterozoic terranes. Within the basin, supply from Proterozoic outcrops is documented locally. Composition varies notably at the western and eastern edges of the sand sea, reflecting partly first-cycle fluvial supply from crystalline basements of Cambrian to Archean age in central Namibia and western Zimbabwe. Basaltic detritus from Jurassic Karoo lavas is dominant in aeolian dunes near Victoria Falls. Bulk-sediment petrography and geochemistry of northern and central Kalahari pure quartzose sand, together with heavy-mineral and clay-mineral assemblages, indicate extensive recycling via aeolian and ephemeral-fluvial processes in arid climate of sediment strongly weathered during previous humid climatic stages in subequatorial Africa. Distilled homogenized composition of aeolian-dune sand thus reverberates the echo of paleo-weathering passed on to the present landscape through multiple episodes of fluvial and aeolian recycling. Intracratonic sag basins such as the Kalahari contain vast amounts of quartz-rich polycyclic sand that may be tapped by rivers eroding backwards during rejuvenation stages associated with rift propagation. Such an event may considerably increase the sediment flux to the ocean, fostering the progradation of river-fed continental-embankments, as documented by augmented accumulation rates coupled with upward increasing mineralogical durability in the post-Tortonian subsurface succession of the Zambezi Delta. The Central Kalahari is not a true desert. It has none of the naked, shifting sand dunes that typify the Sahara and other great deserts of the world. In some years the rains may exceed twenty — once even forty — inches, awakening a magic green paradise.” Mark Owens, Cry of the Kalahari.
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The subequatorial Angolan continental margin offers excellent conditions to test textbook theories on the composition of passive-margin sediments generated in different climatic and tectonic regimes. We use here comprehensive petrographic, heavy-mineral, geochemical and zircon-geochronology datasets on modern fluvial, beach, shelfal, and deep-marine sands and muds collected from hyperarid northern Namibia to hyperhumid Congo to investigate and assess: a) how faithfully sand mineralogy reflects the lithological and time structures of source rocks in a tectonically active rifted margin; b) in what climatic and geomorphological conditions the mark of chemical weathering becomes strong and next overwhelming; and, c) to what extent the effect of weathering can be isolated from quartz dilution by recycling of older siliciclastic strata and other physical controls including hydraulic sorting and mechanical wear. A new refined classification of feldspatho-quartzose and quartzose sands and sandstones is proposed.First-cycle quartzo-feldspathic to feldspar-rich feldspatho-quartzose sand eroded from mid-crustal granitoid gneisses of the Angola Block exposed in the dynamically uplifted Bié-Huila dome is deposited in arid southern Angola, whereas quartz-rich feldspatho-quartzose to quartzose sand characterizes the lower-relief, less deeply dissected, and more intensely weathered rifted margin of humid northern Angola. Pure quartzose, largely recycled sand is generated in the vast, low-lying hyperhumid continental interiors drained by the Congo River. The progressive relative increase of durable minerals toward the Equator results from three distinct processes acting in accord: active tectonic uplift in the arid south, and progressively stronger weathering coupled with more extensive recycling in the humid north. The quartz/feldspar ratio increases and the plagioclase/feldspar ratio decreases rapidly in first-cycle sand generated farther inland in the Catumbela catchment, reflecting stronger weathering in wet interior highlands. Discriminating weathering from recycling control is difficult in northern Angola. Although textural features including deep etch pits even on relatively resistant minerals such as quartz and microcline or rounded outline and abraded overgrowths provide valuable independent information, recycling remains as a most elusive problem in provenance analysis of terrigenous sediments.
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