Basin Research最新文献

{"title":"Spatial distribution of bedforms and related flow processes around canyon mouths: Insights from the Rovuma Basin (offshore Mozambique)","authors":"Yuhang Chen,&nbsp;Yintao Lu,&nbsp;Xiaofeng Wang,&nbsp;Guozhang Fan,&nbsp;Lin Li,&nbsp;Xiaoyong Xu,&nbsp;Guoping Zuo,&nbsp;Dali Shao,&nbsp;Quanbin Cao","doi":"10.1111/bre.12887","DOIUrl":"10.1111/bre.12887","url":null,"abstract":"<p>Bedforms associated with turbidite systems are commonly observed on seafloor. Previous studies have analysed bedform morphological and sedimentary features to determine their formation mechanisms and flow dynamics. However, the seafloor topography and ocean circulation have comprehensively influenced both down- and along-slope turbidity flow processes, complicating the spatial distribution of the related bedforms. Three-dimensional seismic data (3D) were used to depict the morphological and sedimentary features of the bedforms around the canyon mouth on the slope of the Rovuma Basin (offshore Mozambique), to reveal the spatial distribution and related flow processes of the bedforms. The results show that the spatial morphological and sedimentary features of the submarine bedforms at canyon mouths are controlled by the combined action of down- and along-slope factors. The along-slope bottom currents influence the deposition distribution of the turbidity current at the canyon mouth. However, slope breaks control bedform morphological and sedimentary features during downslope turbidity currents. Coarse-grained material of turbidity current flows along the axial zone of the canyon mouth, forming a linear series of crescent-shaped net-erosional cyclic steps characterized by short steep stoss sides and long gentle lee sides. The fine-grained material of the turbidity currents is deflected towards the northern flank of the axial zone by the bottom currents and deposited as undulating net-depositional cyclic steps at upper reach of the northern flank, showing long gentle stoss sides and short steep sides. Slope breaks enhance the erosion on cyclic steps by altering the velocity of turbidity current, forming net-erosional cyclic steps with the manifestation of both short and steep stoss and lee sides at lower reaches of northern flank. The turbidity current in the axial zone formed lateral flow diversions caused by the obstruction of the cyclic steps. The flow diversions converge with the downslope flowing unconfined turbidity current at the northern flank and constitute a confluence characterized by continuous variation of flow properties, forming the cyclic steps featuring irregular morphology.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141726199","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":"Miocene sequences and depocentres in the Roer Valley Rift System","authors":"Alexandra Siebels,&nbsp;Johan ten Veen,&nbsp;Dirk Munsterman,&nbsp;Jef Deckers,&nbsp;Cornelis Kasse,&nbsp;Ronald van Balen","doi":"10.1111/bre.12886","DOIUrl":"10.1111/bre.12886","url":null,"abstract":"<p>The Miocene sequence in the Roer Valley Rift System consists of alternating open-to-shallow marine, coastal and fluvio-deltaic deposits. In this study, well logs, bio-chronostratigraphy and seismostratigraphy are used to characterize major units and their bounding unconformities and to infer sediment dispersal patterns. Three major unconformities occur in the sequence: the early, middle and late Miocene unconformities (EMU, MMU and LMU). The EMU formed due to tectonic motions related to the Savian phase. After formation of the EMU, a broad depocentre developed in the south-eastern part of the Roer Valley Graben (RVG). Sediment accumulation increased during this period and peaked in the middle Langhian, after which it diminished again to a low level during the late Serravallian. The decrease in sediment accumulation coincided with a period of tectonic subsidence along the major bounding fault zones (i.e. the Peel Boundary Fault System, the Feldbiss Fault System and the Veldhoven Fault System). The resulting transgression caused sediment starvation in the central RVG. Subsequently, global sea-level fall during the early Tortonian caused large-scale erosion, and formation of incised valleys on the highs adjacent to the RVG (Peel Block and Campine Block), as well as the south-eastern RVG, forming the MMU. However, sedimentation continued during this period in the central part of the RVG where no erosional hiatus developed. From the Tortonian onwards, accumulation rates increased again. The depocentre shifted towards the north-west and clinoforms developed in the RVG. During the latest Miocene, the depocentre was concentrated along the south-western margin of the RVG. Meanwhile, the depositional environment of the entire RVRS gradually shallowed as the LMU was formed.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12886","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141618458","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":"Unravelling controls on multi-source-to-sink systems: A stratigraphic forward model of the early–middle Cenozoic of the SW Barents Sea","authors":"Amando P. E. Lasabuda,&nbsp;Domenico Chiarella,&nbsp;Tor O. Sømme,&nbsp;Sten-Andreas Grundvåg,&nbsp;Anthony G. Doré,&nbsp;Grandika Primadani,&nbsp;Tom Arne Rydningen,&nbsp;Jan Sverre Laberg,&nbsp;Alfred Hanssen","doi":"10.1111/bre.12883","DOIUrl":"https://doi.org/10.1111/bre.12883","url":null,"abstract":"<p>Source-to-sink dynamics are subjected to complex interactions between erosion, sediment transfer and deposition, particularly in an evolving tectonic and climatic setting. Here we use stratigraphic forward modelling (SFM) to predict the basin-fill architecture of a multi-source-to-sink system based on a state-of-the-art numerical approach. The modelling processes consider key source-to-sink parameters such as water discharge, sediment load and grain size to simulate various sedimentary processes and transport mechanisms reflecting the dynamic interplay between erosion in the catchment area, subsidence, deposition and filling of the basin. The Cenozoic succession along the SW Barents Shelf margin provides a key area to examine controls on source-to-sink systems along a transform margin that developed during the opening of the North Atlantic when Greenland and Eurasian plates were separated (ca. 55 Ma onwards). Moreover, the gradual cooling which culminated in major glaciations in the northern hemisphere during the Quaternary (ca. 2.7 Ma), has affected the spatio-temporal evolution of the sediment routing along the western Barents Shelf margin. This study aims to characterize the relative importance of different source areas within the source-to-sink framework through SFM. In the early Eocene, the SW Barents Shelf experienced a relatively equal sediment delivery from three principal source areas: (i) Greenland to the north, (ii) the Stappen High to the east, representing a local source terrain, and (iii) a major southern source (Fennoscandia). In the middle Eocene, our best-fit modelling scenario suggests that the northern and the local eastern sources dominated over the southern source, collectively supplying large amounts of sand into the basin as evidenced by the submarine fans in Sørvestsnaget Basin. In the Oligocene (ca. 33 Ma) and Miocene (ca. 23 Ma), significant amounts of sediments were sourced from the east due to shelf-wide uplift. Finally, this study highlights the dynamic nature and controls of sediment transfer in multi-source-to-sink systems and demonstrates the potential of SFM to unravel tectonic and climatic signals in the stratigraphic record.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12883","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141584056","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":"New insights into the structural and stratigraphic evolution of the Malay Basin using 3D seismic data: Implications for regional carbon capture and storage potential","authors":"Iain de Jonge-Anderson,&nbsp;Ana Widyanita,&nbsp;Andreas Busch,&nbsp;Florian Doster,&nbsp;Uisdean Nicholson","doi":"10.1111/bre.12885","DOIUrl":"10.1111/bre.12885","url":null,"abstract":"<p>The Malay Basin is a mature hydrocarbon province currently being re-assessed for CO₂ storage. Selecting an appropriate storage site requires a comprehensive understanding of the structural and stratigraphic history of the basin. However, previous studies have been limited to observations from either regional 2D seismic lines or individual 3D seismic volumes. In this study, we access and utilise a basin-wide (ca. 36,000 km²) 3D seismic and well database to describe the structural and stratigraphic features of the basin, particularly those within the uppermost ca. 4 km (Oligocene to Recent) and gain new insights into the basin's evolution. E–W transtensional rift basins first developed due to sinistral shear across an NW-SE strike-slip zone. The NW-SE basin morphology seen today was generated during the late Oligocene–early Miocene, during which time dextral motion across marginal hinge zones created en-echelon antithetic, extensional faults and pull-apart basins, especially well preserved along the western margin of the basin. Collisional forces to the southeast during the early to middle Miocene resulted in the shallowing of the basin, intermittent connection to the South China Sea and a cyclic depositional pattern. Around 8 Ma (late Miocene), a significant uplift of the basin resulted in a major unconformity with up to 4.2 km of erosion and exhumation in the southeast. In the centre and northwest of the basin, the inversion of deeper E–W rifts resulted in the folding of Miocene sequences and the formation of large anticlines parallel to the rift-bounding faults. The Pliocene to Pleistocene history is more tectonically quiescent, but some extensional faulting continued to affect the northwest part of the basin. Larger glacio-eustatic sea-level fluctuations during this time resulted in major changes in sedimentation and erosion on the Sunda Shelf, including the formation of a middle-Pliocene unconformity. These structural events have created a variety of hydrocarbon traps across the basin of different ages, including transpressional anticlines, rollover anticlines and tilted fault blocks. Each of these has discrete and distinct trap elements with important implications for their CO₂ storage potential.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12885","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141557202","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":"Characterization and mapping of continental breakup and seafloor spreading initiation: The example of the northern rifted margin of the South China Sea","authors":"Cuimei Zhang,&nbsp;Gianreto Manatschal,&nbsp;Brian Taylor,&nbsp;Zhen Sun,&nbsp;Minghui Zhao,&nbsp;Jiazheng Zhang","doi":"10.1111/bre.12882","DOIUrl":"10.1111/bre.12882","url":null,"abstract":"<p>Mapping ocean-continent transitions (OCTs) separating equivocal continental and oceanic crusts is fundamental to investigate breakup processes and define the age and location of initial seafloor spreading. However, proposed limits of OCTs are rarely consistent, do not use uniform criteria, and result in conflicting interpretations as shown for the case of the northern South China Sea (SCS). We review original datasets including reflection and refraction seismic sections, drilling and potential field data with the aim to develop a ‘drilling-constrained integrated geological-geophysical’ approach to define the OCT along the northern SCS, understand the breakup process, and to compare the OCT in the SCS with those at Atlantic type rifted margins. The result shows a narrow, 5–15 km wide OCT. It separates a segmented margin that rifted a former arc in the west and a forearc in the east, both facing a Penrose oceanic crust that thins from the west towards the east. Seafloor spreading may have first nucleated at two centres during magnetic anomaly C11 in the NE and central subbasins, which then locally propagated both W and E to break through salients and produce full breakup at 29 Ma (anomaly C10r). Breakup at the SCS shows many differences to Atlantic type margins, in part due to inheritance but also due to rift/spreading-related parameters such as strain/spreading rates.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553406","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":"Geomorphological traits of landscapes in continental rifts—From fault-elastic rebound to sedimentary sinks","authors":"Alvar Braathen,&nbsp;Ivar Midtkandal,&nbsp;Per Terje Osmundsen","doi":"10.1111/bre.12881","DOIUrl":"10.1111/bre.12881","url":null,"abstract":"<p>We analyse 498 faults identified in satellite imagery and interpret the height and width of associated footwall ranges with respect to co-seismic elastic rebound from tectonic and erosional unloading. The dynamics of footwall uplift link uplands to catchment patterns and interrelated hanging wall sedimentary fans. Height–length relations of some catchments and associated alluvial fans scale linearly whereas others, such as fault-slope catchments and related down-fault fans (building out from faults) show a significant scatter without an obvious trend. Perched basins abandoned in the footwalls of younger faults offer catchment-fan height–length relations like watergap and dipslope-related fans and, besides, hint at reduction of dip angle due to rollback of larger faults before abandonment. Analysis of the width-to-height ratio (<i>W</i>/<i>h</i>) of footwall ranges offer a robust linear statistical trend, <i>h</i> = 0.06 W and is identical between datasets. This trend is valid for both arid and tropical rifts, the latter offering smaller rebounds. Contributions of elastic rebound on fault throw in our data are simplistically considered through comparison to global trends on fault length versus throw. This allows consideration around maximum throw (<i>T</i>_max) linked to the maximum height of footwall ranges (<i>h</i>) and to their width (<i>W</i>) above the reference level. Basic calculations indicate that co-seismic rebound contributes from &lt;1% to 17% of extensional fault throw. Width-to-height ratios for large faults (<i>L</i> &gt; c. 50 km) show less spread than smaller faults. Such large faults expectedly dissect the brittle crust, indicating that these large faults which root in the ductile–brittle transition approach a balanced, steady-state kinematic pattern. We speculate that significant crustal thinning associated with these large faults triggers the onset of isostatic adjustments that drive fault rotation, instigating fault abandonment and disconnected perched basins.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12881","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141553525","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":"Late syn-rift to early post-rift basin fill dynamics of a mixed siliciclastic-carbonate succession banked to a basement high, Hornsund, southwestern Spitsbergen, Arctic Norway","authors":"Anders Dahlin,&nbsp;Kasper H. Blinkenberg,&nbsp;Alvar Braathen,&nbsp;Snorre Olaussen,&nbsp;Kim Senger,&nbsp;Aleksandra Smyrak-Sikora,&nbsp;Lars Stemmerik","doi":"10.1111/bre.12880","DOIUrl":"10.1111/bre.12880","url":null,"abstract":"<p>The transition from syn-rift to post-rift sedimentation in rift basins is difficult to characterize in terms of stratigraphic architecture and dominating control on sedimentation, due to decreasing tectonic activity interplaying with regional subsidence, eustatic sea level changes, and differential compaction of underlying syn-rift sediments. Our case study of the Late Palaeozoic Inner Hornsund Fault Zone targets late syn-rift strata recorded in the (?Pennsylvanian – ?lower Permian) Treskelodden Formation in Hornsund, southern Spitsbergen, representing a mixed siliciclastic-carbonate succession, with siliciclastics primarily sourced from the adjacent Sørkapp-Hornsund High. We document local scale (&lt;10 km) facies variability, sequence stratigraphy, and evolution of a succession deposited along a flank of the structural high during the late syn-rift stage. We observe that during the transition towards rift termination (glacio-)eustatic sea level changes and overall regional flooding became a more prominent forcing factor controlling sedimentation. Our dataset includes sedimentary logs, microfacies analysis, and high-resolution digital outcrop models. We identify four progressively backstepping stratigraphic sequences, reflecting an evolution from (1) terrestrial siliciclastics through (2–3) nearshore mixed siliciclastic–carbonates, to (4) carbonate ramp deposits. On the small scale (&lt;5 m) the internal sediment cyclicity of the succession was formed by autogenic processes, particularly the changing rate of sediment input from the southwestern source area (the uplifted Sørkapp-Hornsund basement high). On the larger scale (10s of m), the importance of glacio-eustatic sea-level changes, driven by waxing and waning of ice caps in the southern hemisphere (Gondwana), increased as the rift-related tectonics decreased. The interdisciplinary methods used in this study provide new knowledge of the Middle Pennsylvanian to Permian depositional evolution in southern Spitsbergen, besides a novel framework for comparison to adjacent basins in the region and similar basins elsewhere.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 4","pages":""},"PeriodicalIF":2.8,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12880","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141489788","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":"A fluvial-aeolian system in response to aridification during the Late Mesozoic, Junggar Basin, Central Asia","authors":"Xutong Guan,&nbsp;Chaodong Wu,&nbsp;Yan Xu,&nbsp;Marc Jolivet,&nbsp;Jinlei Xiu,&nbsp;Cong Lin","doi":"10.1111/bre.12879","DOIUrl":"10.1111/bre.12879","url":null,"abstract":"<p>Aridification of Central Asia in the Late Mesozoic led to drastic environmental changes characterized by widespread aeolian deposits. We systematically investigated fluvial-aeolian deposits in the Middle Jurassic Toutunhe Formation, Upper Jurassic Kalazha Formation, and Lower Cretaceous Tugulu Group in the Junggar Basin to the north of the Tianshan Orogenic Belt via unmanned aerial vehicle-based photogrammetry, scanning electron microscope, grain-size analysis, and detrital zircon geochronology. Paludal and deltaic environments transitioned to a fluvial-aeolian environment from the late Middle Jurassic to the Late Jurassic. Fan delta and incisive braided river deposits accumulated in the earliest Cretaceous and evolved into a lacustrine environment with aeolian deposits in the lakeshore. Aeolian deposits are characterized by moderate- to well-sorted and subangular to subround sandstones with large-scale, high-dip cross-bedding, inversely graded lamination, dominant saltation grains, crescent-shaped, and dish-shaped impact structures. Aeolian deposits contain heavy minerals including more ilmenite, zircon, garnet, and, tourmaline and less magnetite and epidote than the fluvial deposits. The preserved aeolian sediments of the Kalazha Formation extend west–east for more than 100 km, suggesting a wide desert area during the latest Jurassic. The detrital zircon age patterns indicate that the provenance of the aeolian deposits was similar to that of coeval fluvial deposits. The cooccurrence of fluvial and aeolian deposits and the similar provenances but orthogonal flow directions indicate that the aeolian deposits were mainly sourced from the nearby fluvial material within the basin. The evolution of the fluvial-aeolian system responded to a complete base-level cycle controlled by the aridification and tectonics. Due to decreased sediment supply caused by aridification, the base level rose, leading to the change from braided rivers to meandering rivers, along with the deposition of aeolian sediments. Due to the tectonic reactivation in the Late Jurassic, the base level fell, causing the occurrence of alluvial fans and the expansion of the aeolian sediments. Previous studies revealed that the Tianshan in the Jurassic exhibited low relief. The fluvial-aeolian system played an important role in maintaining the limited relief in southern Central Asia.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-06-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141334491","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":"Sedimentation tempo in an Early Jurassic erg system: Refined chronostratigraphy and provenance of the Clarens Formation of southern Africa","authors":"Howard V. Head,&nbsp;Emese M. Bordy,&nbsp;Robert Bolhar","doi":"10.1111/bre.12877","DOIUrl":"https://doi.org/10.1111/bre.12877","url":null,"abstract":"<p>The Clarens Formation is a widespread aeolianite deposited over southern Gondwana and represents the final phase of erg evolution in the main Karoo Basin during the Early Jurassic. Previous age assessments of the formation hinge on limited detrital zircon data, supplemented by relative ages from the biostratigraphy and geochronology of the adjacent Karoo units. This study refines the depositional history of the Clarens Formation, including its sediment source dynamics as well as basin-wide geochronological framework, based on U–Pb dating of detrital zircon grains, together with petrographic and sedimentological characterization. The abundant presence of heavy minerals like zircon, tourmaline and rutile suggests large-scale detritus recycling, while the uniform sandstone composition on a regional scale is an indication of sediment homogenisation across the basin. Based on the prominent detrital zircon age fractions, the sediments are interpreted as having been reworked from pre-existing rocks of the Karoo Supergroup (Permian), the Damara and Saldania Orogenic belts (650–490 Ma), whereas minor sources can be assigned to the Namaqua-Natal Mobile Belt (1.35–1.1 Ga) and the western Sierras Pampeanas (1.30–1.33 Ga). Unstable minerals (hornblende, garnet, titanite, feldspar) provide evidence for a nearby granitic source east and southeast of the basin, related to likely Grenvillian rocks (1.0–1.3 Ga). An Early Jurassic zircon age fraction is linked to volcanic activity in the Chon Aike Magmatic Province that, at the time, was situated south and southwest of the study area. Maximum depositional ages derived from these detrital zircon dates suggest that the sedimentation of the Clarens Formation spanned an interval of ~10 Ma during the Pliensbachian and early Toarcian. More specifically, the lower part of the formation is of early Pliensbachian age or younger (~191–192), while the upper part is of early Toarcian age or younger (~181–183 Ma). These age patterns are particularly prominent in the south of the basin that was situated closer to the volcanic source.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12877","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141326672","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":"Re-routing of submarine channels by Plio-Quaternary extensional tectonics along the Tanzania margin and implications for an offshore branch of the East African Rift System","authors":"Marina Dottore Stagna,&nbsp;Vittorio Maselli,&nbsp;David J. Reynolds,&nbsp;Djordje Grujic,&nbsp;David Iacopini,&nbsp;Pamela Reynolds,&nbsp;Sugandha Tewari,&nbsp;Arjan van Vliet","doi":"10.1111/bre.12878","DOIUrl":"https://doi.org/10.1111/bre.12878","url":null,"abstract":"<p>The distribution and timing of Neogene extensional structures along the offshore Tanzania margin and their influence on submarine sediment dispersal pathways remain poorly constrained. This knowledge gap limits understanding of the propagation of the East African Rift System (EARS) in the western Indian Ocean. In this study, we use 2D and 3D seismic reflection data to explore a portion of the upper slope region offshore the Rufiji River delta which led to the discovery of a new extensional structure. Horizon maps and seismic sections extracted from the 3D volume reveal that the slope was intersected by W-E-oriented turbidite channels during the Cenozoic until the early Pliocene (5.3 Ma). Since then, the opening of this graben, whose timing is also constrained by stratigraphic horizon flattening, has led to a southward reorientation of these channels, a pattern that persists today, as evidenced by the flow direction of the channels at the modern seafloor. 2D seismic profiles reaching depths of 10 s two-way travel time (TWT) indicate that the formation of this graben is not related to the reactivation of Mesozoic structures. In detail, seismic data show that the acoustic basement is intersected by extensional faults, likely related to the Jurassic rift tectonics, which is reactivated during the middle Cretaceous forming a gentle monocline. The lack of deformation in the post-Cretaceous suggests a period of tectonic quiescence which persists until the establishment of a new extensional regime responsible for the graben's opening, indicating a decoupling between Mesozoic and Neogene tectonics. Considering the similarity in kinematics, orientation and timing between the graben and other structures along the margin, onshore and offshore, we interpret this graben to be generated by a later tectonic phase of the EARS. These new results may indicate that tectonic stresses associated with the EARS migrated from the Tanzania craton, where the oldest rift structures are dated to ca. 25 Ma, to the western Indian Ocean, where the tectonic activity started during the middle-late Miocene to Pliocene.</p>","PeriodicalId":8712,"journal":{"name":"Basin Research","volume":"36 3","pages":""},"PeriodicalIF":3.2,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1111/bre.12878","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141329353","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}