Basin Research最新文献

{"title":"Lithological influence on sill geometry in sedimentary basins: Controls and recognition in reflection seismic data","authors":"Martin Kjenes,&nbsp;Christian Haug Eide,&nbsp;Agustin Argüello Scotti,&nbsp;Isabelle Lecomte,&nbsp;Nick Schofield,&nbsp;Anna Bøgh","doi":"10.1111/bre.12857","DOIUrl":"https://doi.org/10.1111/bre.12857","url":null,"abstract":"<p>Sills play a leading role in the transport of magma in sedimentary basins. The contact between sills and host rocks reflects the acting emplacement processes during sill propagation and evolution. Recent studies have shown that the propagation of sills and dykes is strongly influenced by the lithology of the host rocks, but none have detailed documentation of marginal features in large-scale intrusive complexes. Three-dimensional seismic data is the primary method of mapping and investigating such complexes, but it is difficult to accurately image sills due to their low thickness compared to seismic resolution. By understanding the relationship between local lithology and marginal sill features, we can better understand the imaging of sills in seismic datasets and their resulting geometry. In this study, we present a seismic-scale sill analogue through multiple high-resolution three-dimensional models, with corresponding logs and field observations from Cedar Mountains, San Rafael Swell, US. This model was further used to develop a synthetic seismic dataset, providing us with a strong control on which marginal sill features fall beneath seismic resolution. We found that lithology plays a critical control in sill geometry and morphology. In Cedar Mountains, sills emplaced within massive sandstones frequently exhibit strata-discordant base contact with the host rock. Conversely, sills found within heterolithic intervals and mudstones typically display strata-concordant base contact with the host rocks. Sills within heterolithic intervals also tend to exhibit a more complex segmentation with multiple broken bridges. Furthermore, our findings show that sills are more than 3.7 times more likely to intrude in mudstone compared to sandstone and heterolithic intervals. These results suggest how sill geometries can be adapted to interpret lithology in seismic datasets from sedimentary basins with little to no well control. We anticipate that our findings may provide better knowledge for interpreting sills in sedimentary basins and contribute to developing more sophisticated geomechanical emplacement models for igneous intrusions.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 2","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12857","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139993926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Geometry and evolution of polygonal fault systems under a regionally anisotropic stress field: Insights from 3D seismic analysis of the Qiongdongnan Basin, NW South China Sea","authors":"Shouxiang Hu,&nbsp;Alte Rotevatn,&nbsp;Christopher Jackson,&nbsp;Wei Li,&nbsp;Xiaochuan Wu","doi":"10.1111/bre.12855","DOIUrl":"https://doi.org/10.1111/bre.12855","url":null,"abstract":"<p>Polygonal fault systems (PFS) are developed in many sedimentary basins, and their formation, growth, and ultimate geometry have been widely studied. The geometry and growth of PFS forming under the influence of regionally anisotropic stresses, however, are poorly understood, despite the fact these structures may serve as key paleo-stress indicators that can help reconstruct the tectonic and stress history of their host basins. We here use high-quality 3D seismic reflection data and quantitative fault analysis to determine the geometry and evolution of a PFS in the Qiongdongnan Basin (NW South China Sea), and its possible relationship with the geological and stress history of the basin. The PFS is dominated by two intersecting NNW-to-N- and E-striking fault sets, which initiated in the Early Miocene. The dominant fault strike at the structural level at which the faults nucleated and where strain is greatest (i.e., Lower Miocene) is close to NW–SE. However, at the top and bottom of the PFS tier faults strike NNW–SSE, thereby defining a very slight vertical, clockwise rotation of strike. Based on the observation that the host rock is flat-lying, it is unlikely that basin-tilting perturbed (i.e., δ2 ≠ δ3) the otherwise radially isotropic stress field that typically characterize PFS. Likewise, diapirs that punctuate the host rock and that are spatially related to the PFS appear not to control fault geometry. We instead infer that the PFS geometry reflects a combination of local isotropic and regional, extension-related tectonics stress affecting the Qiongdongnan Basin during the Early Oligocene to Middle Miocene. Regional studies suggest that during this time, extensional stresses in eastern Qiongdongnan Basin rotated clockwise from roughly NNW to N; we noticed the rotation of strike of the PFS, within which the vertical change in fault strike being relatively minor. Our study determines the timing of polygonal fault growth within the Qiongdongnan Basin and the associated geometry, highlighting the key role played by regional and local stresses.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139942914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-source detrital contributions in the Po alluvial basin (northern Italy) since the Middle Pleistocene. Insights into sediment accumulation in intermediate sinks","authors":"Luca Demurtas,&nbsp;Daniela Fontana,&nbsp;Stefano Lugli,&nbsp;Luigi Bruno","doi":"10.1111/bre.12858","DOIUrl":"https://doi.org/10.1111/bre.12858","url":null,"abstract":"<p>Integrated stratigraphic-compositional studies on alluvial successions provide a valuable tool to investigate the provenance of detritus in multi-source systems. The Po Plain is an intermediate sink of the Po-Adriatic source-to-sink system, fed by rivers draining two orogens. The Alps are characterized by extensive outcrops of plutonic-metamorphic and ultramafic rocks to the north-west and of Mesozoic carbonates to the east (Southern Alps). The Northern Apennines, to the south, are dominated by sedimentary successions. The Po River flows from the Western Alps to the Adriatic Sea, interacting with a dense network of transverse tributaries that drain the two orogens. Stratigraphic, sedimentological and compositional analyses of two 101 and 77.5 m-long cores, recovered from the Central Po Plain, reveal the stacking of three petrofacies, which reflects distinct provenance and configurations of the fluvial network. A South-Alpine sedimentary input between MIS 12 and MIS 10 is testified by petrofacies 1, characterized by carbonate- and volcanic-rich detritus from rocks exposed in the Southern Alps. A northward shift of the Po River of more than 30 km is marked by a quartz-feldspar and metamorphic-rich detritus (petrofacies 2), similar to modern Po River sands. This dramatic reorganization of the fluvial network likely occurred around MIS 9–MIS 8 and is possibly structurally controlled. A further northward shift of the Po River and the onset of Apennine sedimentation in the Late Holocene is revealed by petrofacies 3, rich in sedimentary lithics from the Apennine successions. The results of this study document how compositional analysis, if framed in a robust stratigraphic picture, may provide clues on the evolution of multi-source alluvial systems.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139908839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sensitivity of modelled passive margin stratigraphy to variations in sea level, sediment supply and subsidence","authors":"William J. Schmelz,&nbsp;Kenneth G. Miller,&nbsp;Gregory S. Mountain,&nbsp;Michael S. Steckler,&nbsp;James V. Browning","doi":"10.1111/bre.12854","DOIUrl":"https://doi.org/10.1111/bre.12854","url":null,"abstract":"<p>We produced a 10 Myr synthetic stratigraphic section using a forward stratigraphic model that generates marine deltaic stratigraphy over geological timescales. We recursively fit the model using a Bayesian inversion algorithm to test: (1) if it could be accurately reconstructed; (2) if the parameters used to create it could be recovered; and (3) the sensitivity of the model output to given model parameters and the attendant physical processes. The original synthetic stratigraphic section was produced with cyclical sea-level variations of 40 and 30 m with 2.4 and 10 Myr periods respectively. Sediment was also supplied cyclically, in 2.4 and 10 Myr cycles with amplitudes of 30 and 80 tons/100 kyr, respectively, varying from a mean of 232 tons/100 kyr. Parameter values were sampled to fit the model using a Markov chain Monte Carlo algorithm, resulting in a ±5 m (1σ) variation between the experimental output and the original. Sea level varied by ±7 m (1σ) within the posterior distribution of parameters. As a result, both the 10 Myr and 2.4 Myr sea-level cycles could be extracted from the original output. The variation in sediment supply was approximately ±38 tons/100 kyr (1σ) and, as a result, only the larger long-term supply variations could be accurately recovered in refitting the model. The variation in thermal, flexural and total subsidence across those parameter sets is less than ±10 m (1σ). The original section experienced 150 m of total subsidence at the depocentre. Our results demonstrate the distinct and interpretable imprint of sea level and subsidence on continental margin stratigraphy can be quantified. Moreover, we conclude that sea-level change produces a defined effect on the geometries of stratigraphic architecture, and that techniques applied for the purpose of delineating sea-level variation from continental margin strata have a well-founded conceptual basis.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12854","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139901684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to Integrated uplift, subsidence, erosion and deposition in a tightly coupled source-to-sink system, Pagliara basin, northeastern Sicily, Italy","authors":"","doi":"10.1111/bre.12851","DOIUrl":"https://doi.org/10.1111/bre.12851","url":null,"abstract":"<p>Pavano, F., Pazzaglia, F. J., Rittenour, T. M., Catalano, S., Corbett, L. B., &amp; Bierman, P. (2024). Integrated uplift, subsidence, erosion and deposition in a tightly coupled source- to- sink system, Pagliara basin, northeastern Sicily, Italy. Basin Research, 36, e12845. https://doi.org/10.1111/bre.12845</p><p>In Table 4, the table note was incorrect. This should have read:</p><p>“We used 5.0E-7 yrs for the ¹⁰Be decay constant and 1,386,555 yrs for the half-life. ¹⁰Be exposure is modeled using the CRONUS-Earth online calculators (Balco et al., 2008) to have occurred at a mean elevation of 420 m, which we derived from the assumed steady-state hypsometry of the Pagliara basin (670 m, Pavano et al., 2016), less 250 m of post-middle 300 ka uplift of the Pagliara basin”.</p><p>The References list should include the following:</p><p>Balco, G., Stone, J. O., Lifton, N. A., and Dunai, T. J., 2008, A complete and easily accessible means of calculating surface exposure ages or erosion rates from 10Be and 26Al measurements: Quaternary Geochronology, 3, 174–195.</p><p>In Section 5.2 “Cosmogenic ¹⁰Be paleo-erosion rate data” the text “The measured ¹⁰Be concentrations (Nt) (Table 3) are increased to their decay-corrected burial values (No) using the ¹⁰Be decay constant of 4.3 e-09 yr^-1” was incorrect. This should have read “The measured ¹⁰Be concentrations (Nt) (Table 3) are increased to their decay-corrected burial values (No) using the ¹⁰Be decay constant of 5.0e-7 yr^-1”.</p><p>We apologize for this error.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12851","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139750115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of preexisting structures on salt structures in the Kuqa Depression, Tarim Basin, Western China: Insights from seismic data and numerical simulations","authors":"Keji Yang,&nbsp;Jiafu Qi,&nbsp;Liangwei Xu,&nbsp;Yanqiu Yu,&nbsp;Tong Sun,&nbsp;Fangle Shen,&nbsp;Li Peng,&nbsp;Ji Lv,&nbsp;Hanting Zhao","doi":"10.1111/bre.12850","DOIUrl":"https://doi.org/10.1111/bre.12850","url":null,"abstract":"<p>The preexisting structures that developed in the basement and subsalt strata play a key role in the salt structural deformation in the Kuqa Depression, Tarim Basin. The characteristics of preexisting structures and their controls on the salt structure are investigated via the latest three-dimensional seismic data and numerical modelling. The results show that the preexisting structures that developed in the Kuqa Depression mainly consist of basement faults, palaeouplifts, subsalt slopes and early passive salt diapirs. Basement faults are mainly distributed in the Kelasu and Qiulitag structural belts and control the position of development and deformation style of the Miocene compressive salt structure. The differences in styles and reactivation degrees of basement faults lead to great diversity in the salt structure. The palaeouplifts mainly include the Wensu, western Qiulitag, Xinhe and Yaha-Luntai palaeouplifts. The original sedimentary range and later deformation space of the salt layer are limited by the palaeouplift, resulting in strong salt thrusting in the Awate sag in the western part of the Kuqa Depression. The heterogeneous spatial distribution of the palaeouplift promoted the development of regional strike-slip transform belts. Subsalt slopes are located mainly on the northern edge of the western Qiulitag low uplift and block the southward flow of the salt, causing the salt to form salt domes; the size of these domes is closely related to the subsalt slope. Early passive salt diapirs mainly developed in the Quele and Bozidun areas of the western Kuqa Depression, and they were preferentially active during the compression period, inducing the formation of a piercement salt nappe. Numerical modelling revealed that the preexisting structure strongly controlled the stress–strain distribution during the deformation of the salt structure. The spatial distribution heterogeneity of the basement structure is an important factor in the structural zonation along the north–south strike and segmentation along the west–east strike in the Kuqa Depression, as well as an important inducer of the piercement salt structure.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139750117","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Northward expansion of the Jiaolai Basin during the Early Cretaceous: Insights from source-to-sink reconstruction","authors":"Bo Zhang,&nbsp;Shaofeng Liu,&nbsp;Chengfa Lin,&nbsp;Pengfei Ma","doi":"10.1111/bre.12856","DOIUrl":"https://doi.org/10.1111/bre.12856","url":null,"abstract":"<p>The Jiaolai Basin, situated in the northern Sulu orogenic belt along East Aisa continental margin, preserves evidence of the extensional events in East Asia and the post-orogenic evolution of the Sulu orogenic belt during the Cretaceous period. In this study, multiple provenance analyses were employed to reconstruct the source-to-sink system of the Laiyang Group within the Jiaolai Basin. These studies reveal a history of northward expansion dictated by two significant rift events. During the early Early Cretaceous period (ca. 135–121 Ma), the Zhucheng and Gaomi sags in southern region developed initially. Subsequently, in the late Early Cretaceous period (ca. 120–113 Ma), the Laiyang sag in northern region emerged. Furthermore, these sags were fed by independent source-to-sink systems in their early stages but eventually shared a similar source-to-sink system towards the end of the Laiyang Group deposition (ca. 113 Ma). The provenance analysis results indicate that ca. 121 Ma, ultrahigh-pressure rocks in the northern segment of the Sulu orogenic belt experienced rapid exhumation, while those in the southern segment might have remained concealed until ca. 113 Ma. The two rift events in East Asia, coupled with the alteration in the direction and magnitude of extension documented in the Jiaolai Basin, suggests that trench retreat and the change in subduction direction from E–W to NW–SE of the Izanagi plate played a principal role in driving the extensional events in East Asia during the Early Cretaceous. Our findings imply that the change in Izanagi subduction direction may have occurred ca. 121 Ma.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139750118","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Penecontemporaneous polygonal faulting triggered by sand overloading onto unconsolidated clays: Evidence from the northern South China Sea","authors":"Qingfeng Meng,&nbsp;Fang Hao","doi":"10.1111/bre.12853","DOIUrl":"10.1111/bre.12853","url":null,"abstract":"<p>Layer-bound polygonal fault systems (PFS) are a prevalent feature in fine-grained sediments across many continental margin basins worldwide, yet their origin remains enigmatic. In this study, we report on the structural characteristics of polygonal faults recently discovered in Middle Miocene mudrocks of the Yinggehai Basin, northern South China Sea. Our data reveal that the polygonal arrays of normal faults, which comprise master faults and minor synthetic/antithetic faults with complex tiers, exhibit either straight or curvilinear traces with frequent orthogonal intersections, forming a highly interconnected fault network. We observe several sub-circular to elliptical-shaped depressions that lie above the faulted interval and are filled with syn-deformation deposits, with the long axis of these depressions aligned sub-parallel to the structure contour lines. Our findings suggest that the polygonal faults emerged during the sediment deposition and compaction preceding the deposition of overlying sediments. The faults were created through the nucleation of penecontemporaneous faults due to the overloading of sandy sediments onto unconsolidated clays, followed by the propagation of the faults along with continuous sediment deposition. The cessation of fault propagation coincided with the termination of sedimentation in the faulted interval. Additionally, the local horizontal stress anisotropy resulting from topographic-gravitational effects may have played a crucial role in the development of polygonal faults. Our study provides novel insights into early sediment deformations in the northern South China Sea region and sheds light on the timing and genesis of PFS.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139715405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reconstructing the Zama (Mexico) discovery source to sink palaeogeography, Part II: Sediment routing from the Late Miocene shelf-margin to deepwater basin","authors":"J. W. Snedden,&nbsp;M. G. Rowan,&nbsp;D. F. Stockli,&nbsp;M. Albertson,&nbsp;J. Pasley","doi":"10.1111/bre.12849","DOIUrl":"https://doi.org/10.1111/bre.12849","url":null,"abstract":"<p>The Late Miocene source terrane tectonic history in the southern Gulf of Mexico Basin, as informed by detrital zircon geothermochronology data, supports a detailed regional palaeogeographic reconstruction from palaeoshoreline to the deepwater Zama minibasin of the Sureste salt basin. Seismic mapping points to a trio of pathways that converge upon two entry points into the Zama minibasin, illuminating how sediment gravity flows transit a complex seascape defined by shallow salt bodies. Consideration of empirical scaling relationships within and between segments of this sediment dispersal system allows for testable predictions of Upper Miocene submarine fan-runout lengths over basin exploration areas. Distances from the reconstructed shelf-margin to the Zama wells vary around 100 km, an increase of 20% over a straight-line distance as flows likely navigated around extant salt stocks, walls and sheets. This 100-km fan length is about 40% of the reconstructed minimum palaeo-river length, within predicted ranges for smaller source-to-sink systems in tectonically active areas (25 to 50%). The estimated fan-runout distance can be extended even further basinwards, considering the contemporaneous passage of the mobile Chortis block along the Tonala shear zone, expanding the Palaeo-Rio Grijalva drainage network during the Tortonian. These Late Miocene deepwater systems linked to the Palaeo-Rio Grijalva differ substantially from onshore Mexico-sourced turbidity flows feeding into the axis of the north-trending Veracruz Trough. Textural data from wells here suggests these systems were less effective at larger grain transport and sorting. Local (intrabasinal) variations are also evident within the Zama minibasin, as well data (image logs and cores) indicate that axially oriented sediment gravity flows involved fewer high-density turbidities, depositing lower net-to-gross sandstones and thicker shales than those flowing transverse to the basin axis from a southeastern basin entry point. These interpretations will guide both local exploitation of these economic resources and could also support future exploration for analogous salt-influenced deepwater reservoir systems in the Sureste basin and globally.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139695311","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Neogene evolution of the margin adjacent to the La Plata River Delta (Pelotas Basin): Sedimentary pathways and the origins of the Rio Grande Cone","authors":"Gabriel Tagliaro,&nbsp;Adolfo Britzke,&nbsp;Mateus A. C. Gama,&nbsp;Pedro Bauli,&nbsp;André P. Negrão,&nbsp;Luigi Jovane","doi":"10.1111/bre.12848","DOIUrl":"10.1111/bre.12848","url":null,"abstract":"<p>Continental margins that exhibit high terrigenous input are generally located near deltas that are capable of transporting large quantities of sediments into the basin. However, in rare cases, high terrigenous sedimentation occurs in regions deprived of major riverine systems where the sedimentary pathway is enigmatic. One such case is the Neogene of the Pelotas Basin of Brazil and Uruguay, adjacent to the La Plata River mouth. Since the Miocene, anomalous sedimentation formed a giant progradational wedge, the Rio Grande Cone, one of the largest submarine fan-like features on Earth. To understand the Neogene evolution of the margin and the origins of the Rio Grande Cone, here we present a seismic-stratigraphic framework based on well-logs and 2D seismic data. Three depositional environments are identified: (1) on the shelf, upper Miocene to Pliocene fluvial channels delivered sand deposits on the mud-dominated shelf; (2) on the slope, sediment instability resulted in structural deformation and multiple phases of mass transport deposition and (3) on the lower slope and basin floor, large contourite drifts formed by sediment reworking. We classify the Rio Grande Cone as a megaslide complex, due to its depositional and structural setting. Local deltaic systems were active on the shelf in the Neogene, but the limited size of their paleo-drainage systems in comparison to the volume of sedimentation in the margin suggests that an additional sedimentary pathway existed. In this sense, the demise of an epicontinental sea over the La Plata Basin during the Neogene likely enabled the input of large volumes of fine sediments into the margin, via the La Plata plume water. We suggest that the desiccation of this epicontinental sea and the intensification of ocean currents since the middle Miocene explains the anomalous Neogene terrigenous influx into the SW Atlantic margin.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 1","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139655965","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}