Basin Research最新文献

Sand transport and its deposition in deep marine basins are controlled by diverse climatic, tectonic, physiographic and oceanographic processes. Disentangling the impact of each of these drivers on the sedimentary record is a fundamental challenge in the study of source to sink systems. In this study, we investigate seismic and borehole data by combining statistical and spectral analyses to identify the factors controlling sand deposition in the deep Levant Basin (Eastern Mediterranean) during the Pliocene–Quaternary (PQ). We interpret the sand content in boreholes from gamma ray (GR) logs and identify two major trends in sand/shale ratios. On a million-year scale, we demonstrate that since the Early Pliocene (5.3 Ma), sand content gradually increased until it formed a ca. 100 m thick and widespread sheet of sand at the top of the section. On a shorter time scale, we identify oscillations in sand content depicting significant power of periodic components at the 350–450 ky, 90–150 ky and 10s ky bands. The long-term increase in sand content reaching the deep Levant Basin is interpreted as a result of the Nile Delta propagation, which had continuously shortened the distance between the edge of the Nile delta that is the source of sand, and the deep Levant Basin. The superimposed short-term oscillations are interpreted as Milanković cycles, reflecting hydroclimatic oscillations of water and sediment discharge into the Eastern Mediterranean Sea by the Nile River. This demonstrates the hydroclimatic control on sand deposition in the deep Levant Basin. Our observations are consistent with the development of a submarine channel system along with the accretion of the Nile delta, which may have served as a pathway for sand delivery via high-energy turbidity currents that reached the Levant Basin.

Crustal-scale high-displacement (>10 km) normal faults are not captured in existing tectono-sedimentary models of rift basins. We used 2D and 3D seismic reflection and well data to perform a structural and source-to-sink analysis of the southern part of the Klakk Fault Complex and the western part of the Vingleia Fault Complex, Mid-Norwegian rifted margin. The north–south trending Klakk Fault Complex has a zig-zag to sinuous plan-view geometry, forming a series of structural recesses and salients along strike. In cross-section, the fault complex has a listric to convex-up or low-angle planar geometry with displacements above 20 km. This fault complex exhumed basement highs, the Frøya High and Sklinna Ridge, in its footwall and created a series of supradetachment basins, for example, the Rås Basin, in its hanging wall. In contrast, the northeast-southwest trending Vingleia Fault Complex has a zig-zag geometry in plan view and planar to listric geometry in cross-section and displacement of up to 5 km. This fault has the Frøya High in its footwall and the southern Halten Terrace in its hanging wall. Restoration of selected structural cross-sections shows a prominent fault-parallel ridge, up to 15 km east of the Klakk Fault Complex interpreted as a palaeodrainage divide. This divide separates steep drainages developed along the west-dipping footwall scarp to the Klakk Fault Complex, from broader, gentler east-dipping drainages up to ca. 10 km long developed on a back-tilted dip slopes along the eastern side of the Frøya High and Sklinna Ridge. Progressive headward erosion of active flank catchments was enhanced around topographically elevated structural salients to the point of capturing previous dip-slope-directed drainages during the earliest Cretaceous. A network of submarine canyons develop down-dip of the drainage catchments along the Klakk Fault Complex scarp, whose geometries and length are controlled by their location with respect to the structural salients or recesses, and the presence of fault terraces. The middle Jurassic-earliest Cretaceous synrift deposits form two seismic sequences that are filled with five distinctive seismic facies that record the evolution from a linked normal fault during rift climax to a high-displacement stage. During the high displacement stage, exhumed local continental core complexes formed structural salients, separated along strike by structural recesses at the heads of supradetachment basins. Key elements of the high-displacement fault stage include (i) the development of structural salients at sites of rift climax displacement maxima, (ii) development of supradetachment basins in rift climax displacement minima and (iii) migration of major depocentres away from the centre of rift climax fault segments. We synthesise these observations into a generic tectono-sedimentary model for high-displacement faults.

The Yinggehai Basin is situated at the junction of Indochina and the northern South China Sea (SCS). The origin of the Yinggehai Basin is generally believed to be controlled by the rotation of the Indochina block along the Red River shear zone (RRSZ), which was formed by the collision of India with Asia during the Oligocene. However, the Eocene structural mechanisms of this basin remain debatable. Some studies suggest that the Eocene reactivation of the palaeo-suture zone (which serves as a precursor to the RRSZ) has influenced the region. In contrast, others propose that the NNW–SSE extension of the northern SCS caused by the subduction of the palaeo-SCS towards Borneo in the Eocene has played a significant role. To address these controversies, our study takes into account these two crucial factors using physical analogue modelling. The experimental results, including slow sinistral strike-slip along the palaeo-suture zone and the adjacent NNW–SSE extension, successfully explain the observed fault pattern during the Eocene period. It is noteworthy that the former primarily controlled the Eocene structure in the northern region of the Yinggehai Basin, whereas the latter played a pivotal role in shaping the ENE–WSW Eocene structures on the eastern slope of the basin. The westward propagating faults of the Qiongdongnan basin are cut off by the Yinggehai Basin structures at later large-scale rotation stage. The experiment indicates that the basin evolution exhibits diachronous characteristics, with subsidence in the south occurring later than in the north. Our modelling results provide valuable insights into the key controlling factors that shaped the evolution of the basin during each stage. Furthermore, our findings offer evidence of the interaction between two significant tectonic processes: Indochina extrusion and the opening of the SCS.

The shelf-slope margin is a geomorphic zone with a change in gradient between subaqueous shelves and slopes, which extends towards the submarine basin-floor. It is important because it partitions distinct sedimentary and biogenic processes between the shallow and deep-water realms. The initiation of a shelf-slope profile from pre-existing conditions, and the evolution of shelf margins in space and time has been the focus of numerous studies, particularly from seismic data sets on passive margins, although markedly less-so from active tectonic settings. This study documents the initiation and evolution of a shelf-slope margin in the well-studied Eocene Aínsa Basin (Spanish Pyrenees) through the segmentation of a mixed carbonate-siliciclastic ramp via contractional tectonics and differential subsidence. The basinward propagation of a series of thrusts through the ramp allowed the maintenance of shallow-water, predominantly carbonate sedimentation on their uplifted hanging wall anticlines. Conversely, the deepened foot wall synclines became muddy slope environments, and their axes became the main loci of siliciclastic turbidity current bypass and deposition. The deflection of turbidity currents around uplifted areas towards the synclinal lows allowed for the continuation of carbonate production at the bathymetric highs, which kept pace with subsidence. The interface between shallow- and deep-water sedimentation (i.e. the shelf-slope margin) was an erosional and composite submarine scarp surface generated by several phases of large-scale mass wasting of the aggrading shelf carbonates, and healing by onlap of slope turbidites against the scarp. Continued thrust propagation and basin deepening led to the progressive headward degradation of the surfaces, resulting in an apparent retrogradation of the shelf-slope margin and onlapping slope deposits. This model for the tectonically controlled conversion of a submarine ramp into a shelf-slope profile contrasts with conventional models that consider shelf-slope margins to be inherently progradational after initiation. This study also challenges the notion that large-scale degradational surfaces and thick successions of submarine landslides are inherently diagnostic of canyons and their fill.

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.

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.

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.

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.

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.

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 (W/h) of footwall ranges offer a robust linear statistical trend, h = 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 (T_max) linked to the maximum height of footwall ranges (h) and to their width (W) above the reference level. Basic calculations indicate that co-seismic rebound contributes from <1% to 17% of extensional fault throw. Width-to-height ratios for large faults (L > 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.