Basin Research最新文献

Focusing on the late Miocene succession stratigraphic successions including the evaporite deposits from the Messinian salinity crisis (MSC) of the Adriatic foreland basin, a revision of available boreholes and seismic data allowed us to recognize the presence of reservoirs and seals systems that can be considered of potential interest for the storage of natural and synthetic gas. Potentially good reservoir sites can be found where porous rocks referable to siliciclastic turbiditites (Marnoso-arenacea and Laga Fms) or shallow-water carbonates (Bolognano Fm) preferentially involved in anticlinal structures and covered by thick MSC evaporites, which may represent effective reservoir seals. The integrated reconstruction of porous rocks distribution and facies, thickness, and lateral continuity of the overlying evaporites, allows the identification and zonation of geological settings in the Adriatic foredeep, backbulge and foreland with peculiar stratigraphy and deformations, only partially considered before, that may deserve consideration in the research of potential gas storage sites.

Large clastic dykes (the Harutori-Taro and Harutori-Jiro dykes) and smaller dykes are exposed in the underground Kushiro Coal Mine (KCM), Japan. This study examines these dykes as a case study to investigate the geological conditions and fluid flow history that lead to the development of large clastic dykes in basins. The composition of the dykes indicates the Beppo and/or Harutori formations as their parent unit. Crystallite size distribution (CSD) analysis reveals Ostwald ripening of the kaolinite in the kaolinitised feldspar from the dykes, suggesting stagnant conditions in the parent unit before the dyke was formed. In contrast, smectite CSDs and the high carbonate content of the dykes suggest that large volumes of fluid flowed through the dykes along the established hydraulic gradient, which was triggered by the breaking of the upper seal. The isotopic and chemical compositions of the calcite and aragonite in the dykes, with moderate siderite and rhodochrosite content, indicate the fluid was a warm (>30°C) mixture of freshwater and saltwater, which was transferred from deeper levels of the parent unit towards the crest of an anticline. Immediately after sand injection, the semi-closed system of the parent unit near the root of the large dyke was transformed into a major flow channel for overpressurised fluids. Subsequently, a large volume of fluid flowed along the vertical conduit (or dyke) over a long period of time (>1 Myr), which removed fluid from a widespread area (i.e., several hundred square kilometres) of the basin. The results show that thin parent units, poor lateral continuity of the upper seal, and spatially heterogeneous overpressurisation do not preclude the formation of large dykes.

Unravelling source-to-sink relationships of sediment in coastal regions can be particularly challenging due to a variety of transport directions and mixing within varying local environments in response to sea level fluctuations. Post-glacial sea level rise in the Holocene has resulted in the flooding of former continental margins, locally leading to the separation of islands such as Rottnest in southwest Australia. Rottnest lies approximately 20 km offshore from the mouth of the Swan River, one of the largest permanent river systems across thousands of kilometres of west Australian coastline. In this contribution, we investigate the size, U–Pb age distribution and α-dose values of detrital zircon grains within 13 sand samples collected from three upstream tributaries that drain the Archean Yilgarn Craton, the Swan River estuary, offshore waters surrounding Rottnest Island and modern beaches. We explore sediment derivation, storage and mixing on this passive margin. Carbonate–silicate sands of the region contain detrital zircon with Archean, Mesoproterozoic and Cambro-Neoproterozoic age modes, reflecting regional crystalline basement. Eo- to Paleoarchean zircon grains, including a previously enigmatic >3500 Ma component, are traced from offshore into the estuary, and specifically the Avon River tributary. Detrital mixing models imply an overall fluvial contribution to the estuary and offshore systems of up to 50–65%. By contrast, modern beach samples are dominated by Swan Coastal Plain recycled sediment of up to 96%. The α-dose values of the prominent 3300–3150 Ma age component suggest more efficient fluvial discharge in the Paleo-Swan River than in more recent times. Modern estuary samples have lower average and progressively lower downstream zircon α-dose values, consistent with prolonged chemical and physical reworking and loss of metamict grains with transport distance in the river. We conclude that fluvial drainage networks distribute a locally persistent catchment signal whilst coastal plains in tectonically quiescent settings appear characterized by sediment reprocessing and mixed provenance.

Continental rifts are characterized by up to 30 km wide rotated fault blocks with stratigraphic dip away from the central rift axis. Although gravity-induced mass movements are well known features of collapsed fault block crests, I here demonstrate the occurrence of polymodal gravity-driven mass transport down the back slope of a first-order rift fault block. I identify (1) early sliding related to syntectonic crestal collapse of second-order rift faults, (2) large-scale bed-parallel sliding of the L-M Jurassic sedimentary package, and (3) the accumulation of two 7 km long, 1–2 km wide and up to 750 m thick volumes of complexly slumped material in the hanging walls of two ramp-forming faults. Early sliding is documented by 100 m of repeated Brent Group stratigraphy in a cored well in the study area (well 34/4-15A). These smaller slides have intact internal stratigraphy but show elevated deformation band densities. The seismic data also show evidence for ca. 2 km of massive translational sliding of the ca. 400 m thick and ca. 300 km² large Jurassic section above a lowermost Jurassic bedding-parallel detachment. This translational slide did not deform much internally, except for ductile folding where it slid over underlying active rift faults. Chaotic seismic facies in fault hanging walls are interpreted as contorted Jurassic beds, formed by multiple slumping and sliding events that stacked mobilized sediments into a 750 m thick column. These complex slump volumes occur where fault displacement is highest along two relayed faults. A model is favoured where the large translational slide ruptured with an opening of space against the fault that was progressively filled with slumped material from the footwall. While the large-scale translational sliding only caused moderate internal subseismic deformation, early sliding and, particularly, the complex slumping caused significant internal deformation. This study shows the importance of carefully searching for and distinguishing between different types of mass movement in rift systems.

The McCoy Mountains Formation (McMF) in southern California–Arizona preserves an anomalously thick record of sedimentation during the Mesozoic at a critical time when western North America experienced contrasting tectonic events related to intracontinental rifting along the Mexican Border rift system and consolidation of the North American Cordilleran system. The spaciotemporal interactions among these events and the development of the McCoy basin challenge our understanding of the evolution of the southern extent of North America. At its type locality in the McCoy Mountains, the McMF consists of ~ 7 km of low-grade metasedimentary rocks, originally interpreted as meandering fluvial to alluvial-fan deposits. Uncertainty in the initial timing of sedimentation in the McCoy basin has resulted in multiple tectonic models. We measured ~ 7160 m of detailed stratigraphy and present new sedimentological and detrital zircon results showing that the McCoy basin was occupied by deep-water turbidite systems. These systems deposited an upward-coarsening succession of fine- to coarse-grained detritus during the Cretaceous (ca. 137–70 Ma). Provenance data indicate that the McCoy basin received sediment from Proterozoic basement rocks and metamorphosed Palaeozoic to early Mesozoic sedimentary units. These source rocks are equivalent to the stratigraphy found in the Grand Canyon and Colorado Plateau regions and were likely shed from the southward-advancing Maria fold-thrust belt and possibly the southern Sevier belt in southern Nevada and California. These results, combined with subsidence curves typical of foreland basins, favour deposition within a subaqueous flexural foreland basin system. The presence of a Cretaceous foreland basin this far southwest challenges previously proposed models and suggests that the contractional tectonic regime associated with the North American Cordillera extended into the southwestern most United States during the Early–Late Cretaceous.

The Neogene and Quaternary hinterland basins of the Northern Apennine have been the subject of different tectonic interpretations. Several studies considered these basins as the result of polyphase normal faulting framed in a continuous crustal extensional regime since the middle Miocene. On the contrary, geophysical and geological studies provided evidence of the important role played by out-of-sequence thrusts and backthrusts in the evolution of these basins during a prolongated and intense period of shortening. Here we present an integrated analysis of 2D stacked seismic reflection profiles, stratigraphic and geophysical data from deep exploration wells, gravity data, and published geological and biostratigraphic data for the Valdera-Volterra basin (central Tuscany, Italy). The results support a polyphase and composite evolution of the basin, subdivided into three main phases. During the late Tortonian–Zanclean, the growth of major thrust-related anticlines controlled the evolution of the sedimentary basin. The growth of a syncline determined the creation of accommodation space for the sediments. This main compressional deformation occurred during the Messinian and ended during the Late Zanclean. NE migration of the depocentre during the Early Zanclean was identified, likely possibly due to a differential activity growth between the bordering anticlines. During the Piacenzian, an extensional phase has been recognised, superposed to the previous compressive phase. During the Latest Piacenzian–Early Pleistocene (?), a final compressional phase took place resulting in the positive inversion of the Piacenzian WSW dipping main border fault.

A two-dimensional numerical analysis based on the finite element method and linear elasticity is used to demonstrate how the differential compaction of the basinal unit can cause the early deformation of a prograding and/or aggrading carbonate platform. Our model investigates the modification of the carbonate platform stratal architecture and stress field driven by the process of differential compaction. We compared the results of our model with observations from two Triassic carbonate platforms in the Italian Dolomites: Lastoni di Formin and Nuvolau Mts. (Passo Giau, Italy). We show that the model can explain the modification of stratal architecture, as well as fault and fracture patterns observed on these platforms. In particular, we show that (1) the slope and slope-to-basin transition regions are expected to experience most of the brittle deformation and, differently from what was suggested by previous numerical studies, the formation of platform-ward dipping faults and major fractures with dip angles that tend to decrease moving dip-ward. In addition, (2) the inner platform region can exhibit a slightly tensile regime, which may lead to the formation of syndepositional and/or syndiagenetic fractures. Moreover, (3) in the case of predominantly prograding platforms, the results of the model show a general tilting and thickening of the inner platform strata towards the shelf-slope break.

The Zama discovery was identified off the coast of Tabasco, Mexico, in the Sureste Basin of the Gulf of Mexico and is hosted in a three-way closure in the Upper Miocene. This study conducted a detailed detrital zircon (DZ) U–Pb and (U-Th)/He provenance analyses on samples from sandstone reservoirs in the Zama-3 and Zama-2ST1 wells. A total of 22 sandstone samples (11 from each well) were collected for DZ U–Pb and (U-Th)/He dating from different reservoir zones, testing the hypothesis that different zones were whether originally derived from varied sedimentary source terranes and associated transport pathways to the Zama mini-basin depositional site. Additional objectives include determination of maximum depositional ages, reconstruction of paleofluvial systems, and exploring the temporal evolution of the drainage region and hinterland tectonics. The DZ U–Pb age spectra from both Zama wells have remarkably homogenous DZ signatures with very similar DZ age modes and modal percentages, displaying dominant Permian/Chiapas Batholith (ca. 35%–45%), Mesoproterozoic/Oaxaquian (ca. 20%–35%), Early Palaeozoic/Acatlán (ca. 8%–20%), and Cenozoic magmatic arc (ca. 15%–25%) age modes, as well as some subsidiary (<5%) early Proterozoic/Archean and Early Cretaceous DZ age components, linked to recycled lower Palaeozoic strata and the Guerrero Terrane and Alisitos arc, respectively. Despite differences in paleocurrent directions, deduced from image logs, there are no systematic differences in DZ spectra, indicating a consistent sediment provenance and no changes in source area. All Zama samples analysed in the study are characterized by abundant syn-depositional Late Miocene DZ grains, clustering between 8.6 and 10.2 Ma, corroborating a Tortonian (Late Miocene) depositional age, and yield rapid sediment accumulation rates of ca. 200 m in <1.4 Ma (13 m/Myr). Doubled zircon U–Pb and (U-Th)/He age pairs are indicative of recycling of early Mesozoic rift strata and Paleogene and younger Chiapas basement. These new DZ U–Pb and (U-Th)/He data have a nearly invariant Tortonian sediment provenance that is similar to the modern Grijalva River flowing generally northward out of the Chiapas highlands. The paleo-Grijalva drainage, providing sediment to the Late Miocene Zama mini-basin, was likely drastically larger than the present catchment as it involved 10 Ma plutonic sources that were subsequently downfaulted along the Pacific coast in the latest Miocene. Importantly, DZ U–Pb age components are consistent with Oaxaquia, early Acatlán, and Guerrero/Alisitos signatures and point to sourcing from the Chortis block during its tectonic eastward translation. Such a scenario would allow for a substantially larger Miocene paleo-drainage that would have encompassed both Chiapas and portions of Chortis. The Miocene tectonic translation of Chortis and erosion of a large and tectonically active hinterland would also reconcile the dramatically larger Middle to Late Miocene s

The value of deep-water sedimentary successions as reliable records of environmental change has been questioned due to their long response times and sediment pathways leading to complex responses to climatic change and tectonic signals over differing timescales. We studied the Gulf of Corinth, Greece, to test the value of deep-water stratigraphic successions as records of external controls on sediment flux in a setting with short response times and transport distances. The confinement of the rift basin allows for a near-complete accounting of clastic sediment volumes. The recent acquisition of high-resolution seismic reflection data, utilisation of International Ocean Discovery Programme Expedition 381 cores and a robust chronological framework, enable evaluation of the stratigraphy at a high temporal resolution. Combining borehole and high-resolution seismic reflection data, distinct seismic units can be correlated to multiple paleoenvironmental proxies, permitting quantification of sediment flux variation across successive glacial–interglacial cycles at ca. 10 kyr temporal resolution. Trends in average sediment flux since ca. 242 ka show ca. 2–9 times greater sediment flux in cooler glacials compared to warmer interglacial conditions. The Holocene is an exception to low sediment flux for the interglacials, with ca. 5 times higher rates than previous interglacials. The short and steep configuration of the Sythas canyon and its fan at the base of an active submarine normal fault results in deep-sea deposition at all sea-level stands. In contrast, adjacent canyon systems shut down during warm intervals. When combined with palynology, results show that periods of distinct vegetation re-organisation correlate to sediment flux changes. The temporal correlation of sediment flux to palynology in the Gulf of Corinth over the last ca. 242 kyr is evidence that variability of sediment supply is largely governed by climate-related changes in hinterland catchments, with sea-level and tectonics being second-order controls on sediment flux variability.

Rift initiation within cold, thick, strong lithosphere and the evolving linkage to form a contiguous plate boundary remains debated in part owing to the lack of time–space constraints on kinematics of basement-involved faults. Different rift sectors initiate diachronously and may eventually link to produce a jigsaw spatial pattern, as in the East African rift, and along the Atlantic Ocean margins. The space–time distribution of earthquakes illuminates the geometry and kinematics of fault zones within the crystalline crust, as well as areas with pressurized magma bodies. We use seismicity and Global Navigation System Satellites (GNSS) data from the Turkana Rift Array Investigating Lithospheric Structure (TRAILS) project in East Africa and a new digital compilation of faults and eruptive centres to evaluate models for the kinematic linkage of two initially separate rift sectors: the Main Ethiopian Rift (MER) and the Eastern rift (ER). The ca. 300 km wide zone of linkage includes failed basins and linkage zones; seismicity outlines active structures. Models of GNSS data indicate that the ca. 250 km-wide zone of seismically active en echelon basins north of the Turkana Depression is a zone, or block, of distributed strain with small counterclockwise rotation that serves to connect the Main Ethiopian and Eastern rifts. Its western boundary is poorly defined owing to data gaps in South Sudan. Strain across the northern and southern boundaries of this block, and an ca. 50 km-wide kink in the southern Turkana rift is accommodated by en echelon normal faults linked by short strike-slip faults in crystalline basement, and relay ramps at the surface. Short segments of obliquely oriented basement structures facilitate across-rift linkage of faults, but basement shear zones and Mesozoic rift faults are not actively straining. This configuration has existed for at least 2–5 My without the development of localized shear zones or transform faults, documenting the importance of distributed deformation in continental rift tectonics.