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1
Patton, J. R., C. Goldfinger, A. E. Morey, C. Romsos, B. Black et Y. Djadjadihardja. « Seismoturbidite record as preserved at core sites at the Cascadia and Sumatra–Andaman subduction zones ». Natural Hazards and Earth System Sciences 13, no 4 (4 avril 2013) : 833–67. http://dx.doi.org/10.5194/nhess-13-833-2013.
Texte intégralRésumé :
Abstract. Turbidite deposition along slope and trench settings is evaluated for the Cascadia and Sumatra–Andaman subduction zones. Source proximity, basin effects, turbidity current flow path, temporal and spatial earthquake rupture, hydrodynamics, and topography all likely play roles in the deposition of the turbidites as evidenced by the vertical structure of the final deposits. Channel systems tend to promote low-frequency components of the content of the current over longer distances, while more proximal slope basins and base-of-slope apron fan settings result in a turbidite structure that is likely influenced by local physiography and other factors. Cascadia's margin is dominated by glacial cycle constructed pathways which promote turbidity current flows for large distances. Sumatra margin pathways do not inherit these antecedent sedimentary systems, so turbidity currents are more localized.
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Nelson, C. H., J. Gutiérrez Pastor, C. Goldfinger et C. Escutia. « Great earthquakes along the Western United States continental margin : implications for hazards, stratigraphy and turbidite lithology ». Natural Hazards and Earth System Sciences 12, no 11 (1 novembre 2012) : 3191–208. http://dx.doi.org/10.5194/nhess-12-3191-2012.
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Abstract. We summarize the importance of great earthquakes (Mw &gtrsim; 8) for hazards, stratigraphy of basin floors, and turbidite lithology along the active tectonic continental margins of the Cascadia subduction zone and the northern San Andreas Transform Fault by utilizing studies of swath bathymetry visual core descriptions, grain size analysis, X-ray radiographs and physical properties. Recurrence times of Holocene turbidites as proxies for earthquakes on the Cascadia and northern California margins are analyzed using two methods: (1) radiometric dating (14C method), and (2) relative dating, using hemipelagic sediment thickness and sedimentation rates (H method). The H method provides (1) the best estimate of minimum recurrence times, which are the most important for seismic hazards risk analysis, and (2) the most complete dataset of recurrence times, which shows a normal distribution pattern for paleoseismic turbidite frequencies. We observe that, on these tectonically active continental margins, during the sea-level highstand of Holocene time, triggering of turbidity currents is controlled dominantly by earthquakes, and paleoseismic turbidites have an average recurrence time of ~550 yr in northern Cascadia Basin and ~200 yr along northern California margin. The minimum recurrence times for great earthquakes are approximately 300 yr for the Cascadia subduction zone and 130 yr for the northern San Andreas Fault, which indicates both fault systems are in (Cascadia) or very close (San Andreas) to the early window for another great earthquake. On active tectonic margins with great earthquakes, the volumes of mass transport deposits (MTDs) are limited on basin floors along the margins. The maximum run-out distances of MTD sheets across abyssal-basin floors along active margins are an order of magnitude less (~100 km) than on passive margins (~1000 km). The great earthquakes along the Cascadia and northern California margins cause seismic strengthening of the sediment, which results in a margin stratigraphy of minor MTDs compared to the turbidite-system deposits. In contrast, the MTDs and turbidites are equally intermixed on basin floors along passive margins with a mud-rich continental slope, such as the northern Gulf of Mexico. Great earthquakes also result in characteristic seismo-turbidite lithology. Along the Cascadia margin, the number and character of multiple coarse pulses for correlative individual turbidites generally remain constant both upstream and downstream in different channel systems for 600 km along the margin. This suggests that the earthquake shaking or aftershock signature is normally preserved, for the stronger (Mw ≥ 9) Cascadia earthquakes. In contrast, the generally weaker (Mw = or <8) California earthquakes result in upstream simple fining-up turbidites in single tributary canyons and channels; however, downstream mainly stacked turbidites result from synchronously triggered multiple turbidity currents that deposit in channels below confluences of the tributaries. Consequently, both downstream channel confluences and the strongest (Mw ≥ 9) great earthquakes contribute to multi-pulsed and stacked turbidites that are typical for seismo-turbidites generated by a single great earthquake. Earthquake triggering and multi-pulsed or stacked turbidites also become an alternative explanation for amalgamated turbidite beds in active tectonic margins, in addition to other classic explanations. The sedimentologic characteristics of turbidites triggered by great earthquakes along the Cascadia and northern California margins provide criteria to help distinguish seismo-turbidites in other active tectonic margins.
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Li, Yuting, et Peter D. Clift. « Controls on grain-size variability in the Holocene fill of the Indus Submarine Canyon ». Journal of Sedimentary Research 93, no 2 (8 février 2023) : 71–87. http://dx.doi.org/10.2110/jsr.2022.038.
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ABSTRACT What processes control grain size and bed thickness in submarine canyon deposits? Erosive, shelf-cutting canyons contrast with accretionary basin-floor submarine fan accretionary channels because the former tightly constrain turbidity flows in deep channels. This study addresses such a deep-water depositional system in the Indus Submarine Canyon using a series of cores collected along the canyon. Grain-size analysis was conducted for turbidite and hemipelagic sediment deposited in the Holocene Indus Submarine Canyon mostly by diffuse, fine-grained turbidity currents and hemipelagic hypopycnal plumes. We investigate the links between sedimentary grain size, bedding thickness, facies, and canyon morphology. Well-sorted silt in layers mostly < 2 cm thick dominates the canyon. Core sites in the canyon located downstream of knickpoints have coarser, less well sorted sediments because of current acceleration in these areas and then the slowing of flows downslope. Sediments fine with increasing height above the canyon thalweg, implying deposition from a turbulent plume head. The great depth of the canyon, caused by the exceptionally wide shelf and steep slope, prevents channel overspill which controls sedimentation and channel form in submarine fans. Thalweg sediment fines down-canyon into the mid canyon, where sediment bypassing is inferred. The thickest turbidites are found in the sinuous lower canyon where the gradient shallows from ∼ 0.7° to 0.3°. However, canyon gradient has little impact on mean grain size, but does correlate with bed thickness. The active canyon channel, located in a channel belt gradually becomes less steep, more meandering, and narrower farther downstream. Sinuosity is an influence on turbidite bedding thickness but does not control grain size, in contrast to the situation in submarine-fan channel–levee complexes. Compared to the well-known, more proximal Monterey Canyon of California the grain sizes are much finer, although both systems show evidence of > 200 m plume heads.
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Gong, Chenglin, Ronald J. Steel, Kun Qi et Yingmin Wang. « Deep-water channel morphologies, architectures, and population densities in relation to stacking trajectories and climate states ». GSA Bulletin 133, no 1-2 (15 juin 2020) : 287–306. http://dx.doi.org/10.1130/b35431.1.
Texte intégralRésumé :
Abstract Deep-water channel morphologies, stratigraphy, and population densities in relation to stacking trajectories and climate states remain poorly constrained, and are highlighted by a sampling of 142 submarine channels. From the perspective of channel kinematics, turbidite channels exhibit tripartite lateral - random - vertical trajectories or unidirectional channel-complex trajectories, whereas contourite channels display oblique upslope trajectories. Turbidite channels tend to be deep and narrow and have two to three times more lateral migration than contourite channels, whereas contourite channels tend to be shallow and wide and have two to three times more vertical accretion. We relate such differences between channel morphology and stratigraphy to density contrast between flow and ambient fluid for contourite versus turbidite channels, which seems to have favored lateral channel migration in turbidite channels but channel thalweg deposition in contourite channels. Additionally, channels formed during a greenhouse climate state display low degrees of morphological and architectural variations, and are the minority in our global channel database (8% of total), although the Earth has been in a greenhouse state for 72% of the past 540 m.y. Icehouse channels, in contrast, exhibit high amplitudes of morphological and architectural variations and are the majority in the global channel family (92% of total), although the Earth has been in an icehouse state for 18% of the past 540 m.y. Such differences in channel-population densities between greenhouse and icehouse climates (8% versus 92%) suggest a weak global correlation of channel-population densities with warming greenhouse climates.
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Hesse, Reinhard, Sung Kwun Chough et Allan Rakofsky. « The Northwest Atlantic Mid-Ocean Channel of the Labrador Sea. V. Sedimentology of a giant deep-sea channel ». Canadian Journal of Earth Sciences 24, no 8 (1 août 1987) : 1595–624. http://dx.doi.org/10.1139/e87-155.
Texte intégralRésumé :
The Northwest Atlantic Mid-Ocean Channel (NAMOC) is one of the largest deep-sea channels of the world's oceans. During the late Cenozoic glacial period, the channel played a major role in the depositional history of the Labrador Sea and northwest Atlantic in controlling sedimentation of a broad (approx. 500 m thick and 200 km wide) lens of turbidites. This sediment sequence interfingers laterally with the acoustically transparent pelagic and contourite facies found in the Labrador Basin. The meandering channel is a depositional–erosional feature formed by submarine mass flows, predominantly turbidity currents.The channel contains a meandering talweg that appears to be associated with a sequence of submarine point bars containing thick-bedded, coarse-grained turbidites and gravel layers (channel-fill facies). Old channel positions on seismic profiles indicate that the channel has migrated laterally up to 30 km both to the west and to the east.Natural levees flank the channel for its entire length, extending laterally into turbidite plains 60–100 km wide. The spill-over facies comprises thin-bedded, fine-grained turbidites dominated by thinly laminated muds. Individual units of parallel-laminated mud, which result from single turbidity currents overtopping the channel banks, average 3 cm in thickness. A layer by layer correlation of a sequence of spill-over turbidites is possible between two adjacent cores 70 km apart. Coarse-grained off-channel sediments recently discovered on both levees at distances up to 55 km from the NAMOC occur in tributary channels.Turbidity current activity in the channel probably started with the onset of glaciation at about mid-Pliocene time and ceased at about 7000 years BP, when deglaciation proceeded rapidly. The sedimentation rate for the last episode of overbank deposition on the levees, which probably occurred between 11 000 and 7000 years BP, is 13 cm/1000 years. Towards the end of glacial episodes the northwestern Labrador Sea was probably covered with sea ice.
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Łapcik, Piotr. « Sedimentary processes and architecture of Upper Cretaceous deep-sea channel deposits : a case from the Skole Nappe, Polish Outer Carpathians ». Geologica Carpathica 69, no 1 (1 février 2018) : 71–88. http://dx.doi.org/10.1515/geoca-2018-0005.
Texte intégralRésumé :
AbstractDeep-sea channels are one of the architectonic elements, forming the main conduits for sand and gravel material in the turbidite depositional systems. Deep-sea channel facies are mostly represented by stacking of thick-bedded massive sandstones with abundant coarse-grained material, ripped-up clasts, amalgamation and large scale erosional structures. The Manasterz Quarry of the Ropianka Formation (Upper Cretaceous, Skole Nappe, Carpathians) contains a succession of at least 31 m of thick-bedded high-density turbidites alternated with clast-rich sandy debrites, which are interpreted as axial deposits of a deep-sea channel. The section studied includes 5 or 6 storeys with debrite basal lag deposits covered by amalgamated turbidite fills. The thickness of particular storeys varies from 2.5 to 13 m. Vertical stacking of similar facies through the whole thickness of the section suggest a hierarchically higher channel-fill or a channel complex set, with an aggradation rate higher than its lateral migration. Such channel axis facies cannot aggrade without simultaneous aggradation of levee confinement, which was distinguished in an associated section located to the NW from the Manasterz Quarry. Lateral offset of channel axis facies into channel margin or channel levee facies is estimated at less than 800 m. The Manasterz Quarry section represents mostly the filling and amalgamation stage of channel formation. The described channel architectural elements of the Ropianka Formation are located within the so-called Łańcut Channel Zone, which was previously thought to be Oligocene but may have been present already in the Late Cretaceous.
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Grajales, Viviana Vargas, Tamires Pereira Pinto da Silva, Abelardo Borges Barreto et Sinésio Pesco. « A New Object-Based Algorithm To Simulate Geometrical and Petrophysical Turbidite Channel Properties ». SPE Journal 25, no 05 (16 juin 2020) : 2433–49. http://dx.doi.org/10.2118/199086-pa.
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Summary An object-based algorithm that models turbidite channels using training images, called skeleton-based simulation or SKESIM, is proposed in this study. These images are interpreted as a graph and used to extract the statistical distribution of parameters selected from the graph. From this information, a 3D model of turbidite channel systems was built. These channels were generated within the turbidite lobe, creating a simulated depositional system. After the geometry of the channels were simulated by SKESIM, the petrophysical properties were mapped by Gaussian-like distributions. Numerical simulations were used to fit the simulated permeability field to a reference case through an objective function. A commercial finite difference simulator was used to compare the reference data to the simulated data, and comparable results were obtained.
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Viseur, Sophie. « Turbidite reservoir characterization : object-based stochastic simulation meandering channels ». Bulletin de la Société Géologique de France 175, no 1 (1 janvier 2004) : 11–20. http://dx.doi.org/10.2113/175.1.11.
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Abstract Stochastic imaging has become an important tool for risk assessment and has successfully been applied to oil field management. This procedure aims at generating several possible and equiprobable 3D models of subsurface structures that enhance the available data set. Among these stochastic simulation techniques, object-based approaches consist of defining and distributing objects reproducing underground geobodies. A technical challenge still remains in object-based simulation. Due to advances in deep water drilling technology, new hydrocarbon exploration has been opened along the Atlantic margins. In these turbidite oil fields, segments of meandering channels can be observed on high-resolution seismic horizons. However, no present object-based simulation technique can reproduce exactly such known segments of channel. An improved object-based approach is proposed to simulate meandering turbidite channels conditioned on well observations and such seismic data. The only approaches dealing with meandering channels are process-based as opposed to structure-imitating. They are based on the reproduction of continental river evolution through time. Unfortunately, such process-based approaches cannot be used for stochastic imaging as they are based on equations reflecting meandering river processes and not turbiditic phenomena. Moreover, they incoporate neither shape constraints (such as channel dimensions and sinuosity) nor location constraints, such as well data. Last, these methods generally require hydraulic parameters that are not available from oil field study. The proposed approach aims at stochastically generating meandering channels with specified geometry that can be constrained to pass through well-observations. The method relies on the definition of geometrical parameters that characterize the shape of the expected channels such as dimensions, directions and sinuosity. The meandering channel object is modelled via a flexible parametric shape. The object is defined by a polygonal center-line (called backbone) that supports several sections. Channel sinuosity and local channel profiles are controlled by the backbone and, respectively the sections. Channel generation is performed within a 2D domain, D representing the channel-belt area. The proposed approach proceeds in two main steps. The first step consists in generating a channel center-line (C) defined by an equation v=Z(u) within the domain D. The geometry of this line is simulated using a geostatistical simulation technique that allows the generation of controlled but irregular center-lines conditioned on data points. During the second step, a vector field enabling the curve (C) to be transformed into a meandering curve (C’) is estimated. This vector field acts as a transform that specifies the third degree of channel sinuosity, in other words, the meandering parts of the loops. This field is parameterized by geometrical parameters such as curvature and tangent vectors along the curve (C) and the a priori maximum amplitude of the meander loops of the curve (C’). To make channel objects pass through conditioning points, adjustment vectors are computed at these locations and are interpolated along the curves. Synthetic datasets have been built to check if a priori parameters such as tortuosity are reproduced, and if the simulations are equiprobable. From this dataset, hundred simulations have been generated and enable one to verify that these two conditions are satisfied. Equiprobability is however not always satisfied from data points that are very close and located in a multivalued part of a meander : preferential orientation of the loops may indeed be observed. Solving this issue will be the focus of future works. Nevertheless, the results presented in this paper show that the approach provides satisfying simulations in any other configurations. This approach is moreover well-suited for petroleum reservoir characterization because it only needs specification of geometrical parameters such as dimension and sinuosity that can be inferred from the channel parts seen on seismic horizons or analogues.
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Alpak, Faruk O., Mark D. Barton, Frans F. van der Vlugt, Carlos Pirmez, Bradford E. Prather et Steven H. Tennant. « Simplified Modeling of Turbidite Channel Reservoirs ». SPE Journal 15, no 02 (1 juin 2010) : 480–94. http://dx.doi.org/10.2118/114854-pa.
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Wallet, Bradley C. « Attribute expression of channel forms in a hybrid carbonate turbidite formation ». Interpretation 4, no 2 (1 mai 2016) : SE75—SE86. http://dx.doi.org/10.1190/int-2015-0108.1.
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Much of the world’s conventional oil and gas production comes from turbidite systems. Interpreting them in three dimensions using commercially available software generally requires seismic attributes. Hybrid carbonate turbidite systems are an interesting phenomenon that is not fully understood. I have examined the attribute expression of channel forms in a hybrid carbonate turbidite system from off the coast of Western Australia. I have determined several characteristic responses to attributes that improve the ability to identify and delineate the channel forms. Finally, I have evaluated and developed a workflow that is effective at modeling and extracting the channel forms in three dimensions, leading to a product that can be used in further understanding of how carbonate turbidite systems develop.
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Silver, Clayton, et Heather Bedle. « Evolution of a Late Miocene Deep-Water Depositional System in the Southern Taranaki Basin, New Zealand ». Geosciences 11, no 8 (3 août 2021) : 329. http://dx.doi.org/10.3390/geosciences11080329.
Texte intégralRésumé :
A long-standing problem in the understanding of deep-water turbidite reservoirs relates to how the three-dimensional evolution of deep-water channel systems evolve in response to channel filling on spatiotemporal scales, and how depositional environments affect channel architecture. The 3-D structure and temporal evolution of late Miocene deep-water channel complexes in the southern Taranaki Basin, New Zealand is investigated, and the geometry, distribution, and stacking patterns of the channel complexes are analyzed. Two recently acquired 3-D seismic datasets, the Pipeline-3D (proximal) and Hector-3D (distal) are analyzed. These surveys provide detailed imaging of late Miocene deep-water channel systems, allowing for the assessment of the intricate geometry and seismic geomorphology of the systems. Seismic attributes resolve the channel bodies and the associated architectural elements. Spectral decomposition, amplitude curvature, and coherence attributes reveal NW-trending straight to low-sinuosity channels and less prominent NE-trending high-sinuosity feeder channels. Stratal slices across the seismic datasets better characterize the architectural elements. The mapped turbidite systems transition from low-sinuosity to meandering high-sinuosity patterns, likely caused by a change in the shelf-slope gradient due to localized structural relief. Stacking facies patterns within the channel systems reveal the temporal variation from a depositional environment characterized by sediment bypass to vertically aggrading channel systems.
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Yang, Bo, Hongjun Qu, Jianchao Shi, Yuqi Bai, Wenhou Li, Yanrong Zheng et Rongjun Zhang. « The Lithological Features of Sublacustrine Fans and Significance to Hydrocarbon Exploration : A Case Study of the Chang 7 Interval of the Yanchang Formation, Southeastern Ordos Basin, North China ». Geofluids 2021 (7 mai 2021) : 1–22. http://dx.doi.org/10.1155/2021/5583191.
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The Chang 7 interval of the Upper Triassic Yanchang Formation in the Ordos Basin represents a typical deep lacustrine depositional sequence. On the basis of field outcrops, cores, well logs, light/heavy mineral provenance analysis, and petrological studies, we evaluated the characteristics of deep-water gravity flow deposition of the Chang 7 interval and constructed a depositional model. The sediments mainly came from the northeast of the study area, and multiple sublacustrine fans were deposited in the center of the basin. Different from the deep-marine fan, the sublacustrine fan in the study area develops under the background of gentle slope without any erosional canyon between the fan and delta front. Gravity flow deposits in the study area can categorised into three groups: sand debris flow deposits, turbidity current deposits, and deep-water mudstone deposits. The main channel and branch channel are mainly developed with thick massive sandy debris sandstone, while the channel lateral margin and branch channel lateral margin are mainly developed with middle massive sandy debris sandstones and turbidite sandstones, which from bottom to top, the thickness of sand layer becomes thinner and the grain size becomes smaller. Thin mudstone is developed between channels; the lobe fringe includes sheet-like turbidite sandstones and deep lake mudstones. The widely distribute, good quality source rocks ( TOC = 2 % – 6 % ) developed in deep lacustrine have attained the peak stage of oil generation ( R o = 0.9 % – 1.2 % ). The superimposition of the sublacustrine fan sand bodies and the wide distribution of good quality source rocks favor the formation of large lithologic reservoirs characterized by source–reservoir integration, self-generation and self-storage, and near-source accumulation.
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Sherlock, Don, Leigh Scoby-Smith et Eamonn Montague. « Time-lapse analogue modelling of turbidite channel sands ». ASEG Extended Abstracts 2004, no 1 (décembre 2004) : 1–4. http://dx.doi.org/10.1071/aseg2004ab128.
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Myers, Robert A., et David J. W. Piper. « Seismic stratigraphy of late Cenozoic sediments in the northern Labrador Sea : a history of bottom circulation and glaciation ». Canadian Journal of Earth Sciences 25, no 12 (1 décembre 1988) : 2059–74. http://dx.doi.org/10.1139/e88-191.
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The seismicstratigraphy of the upper 1 km of sediment in the northern Labrador Sea has been determined from the examination of about 26 000 line kilometres of seismic profiles. Four key reflectors (A to D) have been correlated with Deep Sea Drilling Project (DSDP) and Ocean Drilling Program (ODP) holes and range in age from mid-Pliocene to approximately mid-Pleistocene. Ten seismic facies have been distinguished and are interpreted as resulting from slope progradation, turbidite deposition in channels and on the basin floor, and widespread contourite deposition.Tertiary sediments are predominantly hemipelagic or contourite, but in the mid-Pliocene, turbidite deposition began in the northeast Labrador Basin, which might reflect either Greenland glaciation or lowering of sea level. At the same time, widespread erosion and buildup of drift deposits indicate that there was an intensification of bottom-water circulation, probably reflecting high-latitude cooling. This was followed by a return to less dynamic conditions as increased sea-ice cover reduced bottom-water generation in high-latitude seas. A turbidite deep-sea fan developed off Hudson Strait in the Early Pleistocene. In the mid- and late Quaternary, there was a major increase in the supply of turbidites from the Labrador margin, accompanied by the development of an extensive channel system on the continental margin. This was a consequence of glacial ice sheets extending to the top of the continental slope and discharging sediment directly to deep water.
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Lin, Yani, Tianze Zhang et Kelly H. Liu. « Turbidite lobe deposits in a canyon-fill system ». Interpretation 9, no 2 (7 avril 2021) : C17—C21. http://dx.doi.org/10.1190/int-2020-0111.1.
Texte intégralRésumé :
Geological feature: Turbidite lobe deposits in a canyon-fill system Seismic appearance: Isolated and irregularly shaped sandstone pods Alternative interpretations: Mid-channel bars in a braided channel system Features with similar appearance: Alluvial fans Formation: Lower Wilcox Group Age: Late Paleocene to Early Eocene Location: Shelf edge at the Central Gulf Coast Region of Texas Seismic data: Donated by a petroleum exploration company in Houston, Texas Analysis tools: Seismic attributes such as instantaneous phase, root-mean-square amplitude, and spectral decomposition
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Fuhrmann, A., I. A. Kane, M. A. Clare, R. A. Ferguson, E. Schomacker, E. Bonamini et F. A. Contreras. « Hybrid turbidite-drift channel complexes : An integrated multiscale model ». Geology 48, no 6 (18 mars 2020) : 562–68. http://dx.doi.org/10.1130/g47179.1.
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Abstract The interaction of deep-marine bottom currents with episodic, unsteady sediment gravity flows affects global sediment transport, forms climate archives, and controls the evolution of continental slopes. Despite their importance, contradictory hypotheses for reconstructing past flow regimes have arisen from a paucity of studies and the lack of direct monitoring of such hybrid systems. Here, we address this controversy by analyzing deposits, high-resolution seafloor data, and near-bed current measurements from two sites where eastward-flowing gravity flows interact(ed) with northward-flowing bottom currents. Extensive seismic and core data from offshore Tanzania reveal a 1650-m-thick asymmetric hybrid channel levee-drift system, deposited over a period of ∼20 m.y. (Upper Cretaceous to Paleocene). High-resolution modern seafloor data from offshore Mozambique reveal similar asymmetric channel geometries, which are related to northward-flowing near-bed currents with measured velocities of up to 1.4 m/s. Higher sediment accumulation occurs on the downstream flank of channel margins (with respect to bottom currents), with inhibited deposition or scouring on the upstream flank (where velocities are highest). Toes of the drift deposits, consisting of thick laminated muddy siltstone, which progressively step back into the channel axis over time, result in an interfingering relationship with the sandstone-dominated channel fill. Bottom-current flow directions contrast with those of previous models, which lacked direct current measurements or paleoflow indicators. We finally show how large-scale depositional architecture is built through the temporally variable coupling of these two globally important sediment transport processes. Our findings enable more-robust reconstructions of past oceanic circulation and diagnosis of ancient hybrid turbidite-drift systems.
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Labourdette, Richard. « ‘LOSCS’ Lateral Offset Stacked Channel Simulations : Towards geometrical modelling of turbidite elementary channels ». Basin Research 20, no 3 (4 juin 2008) : 431–44. http://dx.doi.org/10.1111/j.1365-2117.2008.00361.x.
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Hill, Jenna C., Janet T. Watt, Daniel S. Brothers et Jared W. Kluesner. « Submarine canyons, slope failures and mass transport processes in southern Cascadia ». Geological Society, London, Special Publications 500, no 1 (2020) : 453–75. http://dx.doi.org/10.1144/sp500-2019-169.
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AbstractMarine turbidite records have been used to infer palaeoseismicity and estimate recurrence intervals for large (>Mw7) earthquakes along the Cascadia Subduction Zone. Conventional models propose that upper slope failures are funneled into submarine canyons and develop into turbidity flows that are routed down-canyon to deep-water channel and fan systems. However, the sources and pathways of these turbidity flows are poorly constrained, leading to uncertainties in the connections between ground shaking, slope failure and deep-water turbidites. We examine the spatial distribution of submarine landslides along the southern Cascadia margin to identify source regions for slope failures that may have developed into turbidity flows. Using multibeam bathymetry, sparker multichannel seismic and chirp sub-bottom data, we observe relatively few canyon head slope failures and limited evidence of large landslides on the upper and middle slope. Most of the submarine canyons are draped with sediment infill in the upper reaches and do not appear to be active sediment conduits during the recent sea-level highstand. In contrast, there is evidence of extensive mass wasting of the lower slope and non-channelized downslope flows. Contrary to previous studies, we propose that failures along the lower slope are the primary sources for deep-sea seismoturbidites in southern Cascadia.
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Don, Sherlock, Scoby-Smith Leigh et Montague Eamonn. « Time-Lapse Analogue Reservoir Modelling of Turbidite Channel Sands ». Exploration Geophysics 36, no 2 (juin 2005) : 216–23. http://dx.doi.org/10.1071/eg05216.
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Bashirova, L. D., E. V. Dorokhova et V. V. Sivkov. « Lithodynamic studies near the Northwest Atlantic Mid-ocean channel ». Океанология 59, no 5 (5 novembre 2019) : 803–9. http://dx.doi.org/10.31857/s0030-1574595803-809.
Texte intégralRésumé :
In AMK-4474 marine sediment core, recovered from the northern part of the eastern (left) levee of the Northwest Atlantic Mid-Ocean Channel, two stratigraphic units were identified. The lower unit is represented by the Late Quaternary fine-grained sediments of the upper turbidite sequences. The presence of a 1724 m mode in grain-size distributions within the thin silt interlayers in the lower unit may reflect a sorting process of sedimentary material by the spillover of turbidity currents which is similar to the contour currents activity. This allows applying an indicator of the contour current speed sortable silt (SS) content to estimate the intensity of the spill-over current. The upper unit, formed during the last 26 ka, is represented by pelagic sediments. The presence of the fine-grained interlayer in the upper unit of AMK-4474 core is apparently due to a decrease in IRD supply to the study area.
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Steventon, Michael J., Christopher A. L. Jackson, Howard D. Johnson, David M. Hodgson, Sean Kelly, Jenny Omma, Christine Gopon, Christopher Stevenson et Peter Fitch. « Evolution of a sand-rich submarine channel–lobe system, and the impact of mass-transport and transitional-flow deposits on reservoir heterogeneity : Magnus Field, Northern North Sea ». Petroleum Geoscience 27, no 3 (25 février 2021) : petgeo2020–095. http://dx.doi.org/10.1144/petgeo2020-095.
Texte intégralRésumé :
The geometry, distribution and rock properties (i.e. porosity and permeability) of turbidite reservoirs, and the processes associated with turbidity current deposition, are relatively well known. However, less attention has been given to the equivalent properties resulting from laminar sediment gravity-flow deposition, with most research limited to cogenetic turbidite debrites (i.e. transitional-flow deposits) or subsurface studies that focus predominantly on seismic-scale mass-transport deposits (MTDs). Thus, we have a limited understanding of the ability of subseismic MTDs to act as hydraulic seals, and their effect on hydrocarbon production and/or carbon storage. We investigate the gap between seismically resolvable and subseismic MTDs, and transitional-flow deposits on long-term reservoir performance in this analysis of a small (<10 km-radius submarine fan system), Late Jurassic, sandstone-rich stacked turbidite reservoir (Magnus Field, Northern North Sea). We use core, petrophysical logs, pore fluid pressure, quantitative evaluation of minerals by scanning electron microscopy (QEMSCAN) and 3D seismic-reflection datasets to quantify the type and distribution of sedimentary facies and rock properties. Our analysis is supported by a relatively long (c. 37 years) and well-documented production history. We recognize a range of sediment gravity deposits: (i) thick-/thin-bedded, structureless and structured turbidite sandstone, constituting the primary productive reservoir facies (c. porosity = 22%, permeability = 500 mD); (ii) a range of transitional-flow deposits; and (iii) heterogeneous mud-rich sandstones interpreted as debrites (c. porosity ≤ 10%, volume of clay = 35%, up to 18 m thick). Results from this study show that over the production timescale of the Magnus Field, debrites act as barriers, compartmentalizing the reservoir into two parts (upper and lower reservoir), and transitional-flow deposits act as baffles, impacting sweep efficiency during production. Prediction of the rock properties of laminar- and transitional-flow deposits, and their effect on reservoir distribution, has important implications for: (i) exploration play concepts, particularly in predicting the seal potential of MTDs; (ii) pore-pressure prediction within turbidite reservoirs; and (iii) the impact of transitional-flow deposits on reservoir quality and sweep efficiency.Supplementary material: of data and methods are available at https://doi.org/10.6084/m9.figshare.c.5313860
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Kneller, Ben. « The influence of flow parameters on turbidite slope channel architecture ». Marine and Petroleum Geology 20, no 6-8 (juin 2003) : 901–10. http://dx.doi.org/10.1016/j.marpetgeo.2003.03.001.
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Yu, Zhenghong, Si Chen, Weidong Xie, Shu’e Zhao, Jianghao Ma et Tianhao Gong. « Implication Linkage among Microfacies, Diagenesis, and Reservoir Properties of Sandstones : A Case Study of Dongying Formation, Nanpu Sag, Bohai Bay Basin ». Energies 15, no 20 (20 octobre 2022) : 7751. http://dx.doi.org/10.3390/en15207751.
Texte intégralRésumé :
The reservoir quality of sandstones is significantly impacted and transformed by sedimentation and diagenesis. It is necessary to clarify the internal relationship among them to precisely predict the sweet reservoir. In this study, five types of sedimentary microfacies are recognized through core observation and logging data: submerged distributary channel (fan delta), submerged interdistributary bay, submerged distributary channel (braided delta), distal bar, and turbidite fan. The major diagenetic processes, including compaction, cementation, and dissolution, have been analyzed based on petrography, scanning electron microscopy, and X-Ray diffraction. The dominant diagenetic cement includes calcite, smectite, kaolinite, illite, and I/S mixed-layer minerals, with small quantities of chlorite, pyrite, siderite, feldspar, and quartz cement. The reservoir quality is best in the submerged distributary channel (fan delta) sandstones, followed by submerged distributary channel (braided delta). Submerged interdistributary bay, distal bar, and turbidite fan are of poor reservoir quality. The grain size is the primary reservoir quality controlling factor, highly affected by sedimentary microfacies. Subsequent controls are diagenetic processes such as mechanical compaction, clay minerals formation, grain replacement, and dissolution that collectively influence the porosity and permeability.
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Mohd Radzir, Nurul Afifah, Che Aziz Ali et Kamal Roslan Mohamed. « Sedimentological Analysis of the Turbidite Sequence in the Northern Part of the West Crocker Formation, Northwest Sabah ». Applied Sciences 12, no 23 (28 novembre 2022) : 12149. http://dx.doi.org/10.3390/app122312149.
Texte intégralRésumé :
Gravity-flow deposits form the northern part of the Crocker Formation (Oligocene–Early Miocene), with the most significant interpretation as a sand-rich system in the proximal and a mud-rich system in the distal area of the deep-water turbidite depositional setting. Seven outcrop localities in the northern-part area were selected for mapping and sampling, starting from Kota Kinabalu up to the Telipok area to evaluate the sedimentary sequence. This study used mapping, field observation, and log sketches in the field, as well as extensive analysis and interpretation of sedimentological methods to investigate the sequence of sediment outcrops in the Crocker Formation area of northwest Sabah. During the fieldwork, five main facies were found, namely, massive sandstone facies (f1), graded sandstone facies (f2), laminated sandstone facies (f3), interbedded sandstone and mudstone facies (f4), and mudstone facies (f5). These northern-part outcrops are interpreted as being deposited from the highest to the lowest turbidity currents and the actuality of pelagic mudstone deposition, based on their fining-coarsening-upward pattern. The five geometrical bodies were proposed as laterally contiguous depositional environments, namely, (1) inner fan channel, (2) inner fan channel–levee complex, (3) mid-fan channelized lobes, (4) non-channelized lobes/distal lobes, and (5) basin plains. The facies interpretation shows that the study area consists of lobes, channel–levee complexes, and levees formed in a fan of a deep-water basin setting, with the basinal plain enveloped by thick mudstone deposits. This northern part of the Crocker Formation is interpreted as a multiple-sourced sediment, shelf-fed, Type II, low-efficiency, and sand-rich turbidite depositional system.
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Johnson, Kyle, Kathleen M. Marsaglia, Philipp A. Brandl, Andrew P. Barth, Ryan Waldman, Osamu Ishizuka, Morihisa Hamada, Michael Gurnis et Ian Ruttenberg. « Intra-oceanic submarine arc evolution recorded in an ~1-km-thick rear-arc succession of distal volcaniclastic lobe deposits ». Geosphere 17, no 4 (14 mai 2021) : 957–80. http://dx.doi.org/10.1130/ges02321.1.
Texte intégralRésumé :
Abstract International Ocean Discovery Program (IODP) Expedition 351 drilled a rear-arc sedimentary succession ~50 km west of the Kyushu-Palau Ridge, an arc remnant formed by rifting during formation of the Shikoku Basin and the Izu-Bonin-Mariana arc. The ~1-km-thick Eocene to Oligocene deep-marine volcaniclastic succession recovered at Site U1438 provides a unique opportunity to study a nearly complete record of intra-oceanic arc development, from a rear-arc perspective on crust created during subduction initiation rather than supra-subduction seafloor spreading. Detailed facies analysis and definition of depositional units allow for broader stratigraphic analysis and definition of lobe elements. Patterns in gravity-flow deposit types and subunits appear to define a series of stacked lobe systems that accumulated in a rear-arc basin. The lobe subdivisions, in many cases, are a combination of a turbidite-dominated subunit and an overlying debris-flow subunit. Debris flow–rich lobe-channel sequences are grouped into four, 1.6–2 m.y. episodes, each roughly the age range of an arc volcano. Three of the episodes contain overlapping lobe facies that may have resulted from minor channel switching or input from a different source. The progressive up-section coarsening of episodes and the increasing channel-facies thicknesses within each episode suggest progressively prograding facies from a maturing magmatic arc. Submarine geomorphology of the modern Mariana arc and West Mariana Ridge provide present-day examples that can be used to interpret the morphology and evolution of the channel (or channels) that fed sediment to Site U1438, forming the sequences interpreted as depositional lobes. The abrupt change from very thick and massive debris flows to fine-grained turbidites at the unit III to unit II boundary reflects arc rifting and progressive waning of turbidity current and ash inputs. This interpretation is consistent with the geochemical record from melt inclusions and detrital zircons. Thus, Site U1438 provides a unique record of the life span of an intra-oceanic arc, from inception through maturation to its demise by intra-arc rifting and stranding of the remnant arc ridge.
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Felletti, Fabrizio, George Pantopoulos, Chiara Zuffetti, Simone Reguzzi, Daniele Invernizzi, Niccolò Bellin, Mattia Marini et al. « The Tachrift Project : sedimentary architecture of turbidite channel- levée deposits (Tachrift Turbidite System, Taza-Guercif Basin, Tortonian, NE Morocco) ». Rendiconti Online della Società Geologica Italiana 59 (mars 2023) : 1–9. http://dx.doi.org/10.3301/rol.2023.13.
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Marini, Mattia, Giovanna Della Porta, Fabrizio Felletti, Benedetta Marcella Grasso, Marica Franzini et Vittorio Casella. « Insight into Heterogeneous Calcite Cementation of Turbidite Channel-Fills from UAV Photogrammetry ». Geosciences 9, no 5 (23 mai 2019) : 236. http://dx.doi.org/10.3390/geosciences9050236.
Texte intégralRésumé :
Diagenesis is a key controlling factor on sandstone porosity and permeability. Understanding type, paragenetic sequence and spatial patterns of cements is thus important for assessing sandstone hydrocarbon reservoir properties. In this study Unmanned Aerial Vehicle (UAV) photogrammetry is used to evaluate the shape and spatial distribution of calcite concretions developed within the sand-prone fill of a turbidite channel. The studied channel-fill is entrenched into hemipelagic marlstones and include a lower conglomeratic sandstone loaded with marlstone rip-ups and an upper fill featuring a range of turbidite bed types, which, up-section and off the channel axis, are progressively finer grained and less amalgamated. Concretion shape analysis highlighted a continuum of equant to oblate shapes with flat-lying major axes and a cumulative volume fraction of ca. 22%. Equant to sub-equant concretions are ubiquitous and occur at different heights within beds, often developing around marlstone rip-ups. Conversely, elongated concretions are either strata-bound concretions or completely cemented beds which become volumetrically dominant up section and off the channel axis. The interparticle pore-space of concretions represents on average ca. 22% and is tightly filled by poikilotopic and blocky calcite cement precipitated near to maximum burial depth, whereas host sandstones lack calcite cements and show smectite clay cement and an average preserved porosity of ca. 15%. The oxygen and carbon isotopes of calcite cements point to the marlstone as the main source of carbonate ions, suggesting concretions developed during burial by either diffusion from rip-ups and mud caps or recrystallization of, matrix micrite. Results suggest that the process by which the carbonate-rich component was eroded from the substrate and trapped within the channel-fill is a key control on spatial distribution of calcite concretions, likely to reflect on spatial variability of reservoir properties.
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Mayall, Mike, Ed Jones et Mick Casey. « Turbidite channel reservoirs—Key elements in facies prediction and effective development ». Marine and Petroleum Geology 23, no 8 (septembre 2006) : 821–41. http://dx.doi.org/10.1016/j.marpetgeo.2006.08.001.
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Ferguson, Mark E., John WF Waldron et Wouter Bleeker. « The Archean deep-marine environment : turbidite architecture of the Burwash Formation, Slave Province, Northwest Territories ». Canadian Journal of Earth Sciences 42, no 6 (1 juin 2005) : 935–54. http://dx.doi.org/10.1139/e04-070.
Texte intégralRésumé :
The Slave Province is an Archean craton that contains an unusually large proportion of preserved sedimentary rock, including thick turbidite successions. The Burwash Formation is exposed in the southern Slave Province between the Anton and Sleepy Dragon basement massifs. At the base of the succession, volcanics and clastic metasedimentary rocks of the Raquette Lake Formation record initiation of the basin in a rifted arc environment. These are overlain by thin black slates representing a transgression, followed by well over 5 km of Burwash Formation metamorphosed turbiditic sandstones and slates interspersed with thin felsic tuff layers. Lateral correlation within the formation is possible using airphotos and recognizable tuff units. Burwash Formation sandstones include thinly bedded units displaying Bouma sequences and thicker bedded units with scour-and-fill structures and stratification bands, characteristic of dense sediment gravity flows. The sedimentary rocks are organized in architectural elements that include channel-fill sandstones and conglomerates, muddy levees, interchannel sandstones resembling high-amplitude reflection packages (HARPs) described from modern fans, and possible depositional lobes. The overall sedimentary architecture was probably controlled by events in the tectonically active source area or areas. The Archean turbidites resemble their Phanerozoic and modern analogues, although they show less voluminous levees, and are generally less organized, than large modern passive-margin fans, which probably have no equivalents in the Archean.
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Hamilton, T. S., Randolph J. Enkin, Michael Riedel, Garry C. Rogers, John W. Pohlman et Heather M. Benway. « Slipstream : an early Holocene slump and turbidite record from the frontal ridge of the Cascadia accretionary wedge off western Canada and paleoseismic implications ». Canadian Journal of Earth Sciences 52, no 6 (juin 2015) : 405–30. http://dx.doi.org/10.1139/cjes-2014-0131.
Texte intégralRésumé :
Slipstream Slump, a well-preserved 3 km wide sedimentary failure from the frontal ridge of the Cascadia accretionary wedge 85 km off Vancouver Island, Canada, was sampled during Canadian Coast Guard Ship (CCGS) John P. Tully cruise 2008007PGC along a transect of five piston cores. Shipboard sediment analysis and physical property logging revealed 12 turbidites interbedded with thick hemipelagic sediments overlying the slumped glacial diamict. Despite the different sedimentary setting, atop the abyssal plain fan, this record is similar in number and age to the sequence of turbidites sampled farther to the south from channel systems along the Cascadia Subduction Zone, with no extra turbidites present in this local record. Given the regional physiographic and tectonic setting, megathrust earthquake shaking is the most likely trigger for both the initial slumping and subsequent turbidity currents, with sediments sourced exclusively from the exposed slump face of the frontal ridge. Planktonic foraminifera picked from the resedimented diamict of the underlying main slump have a disordered cluster of 14C ages between 12.8 and 14.5 ka BP. For the post-slump stratigraphy, an event-free depth scale is defined by removing the turbidite sediment intervals and using the hemipelagic sediments. Nine 14C dates from the most foraminifera-rich intervals define a nearly constant hemipelagic sedimentation rate of 0.021 cm/year. The combined age model is defined using only planktonic foraminiferal dates and Bayesian analysis with a Poisson-process sedimentation model. The age model of ongoing hemipelagic sedimentation is strengthened by physical property correlations from Slipstream events to the turbidites for the Barkley Canyon site 40 km south. Additional modelling addressed the possibilities of seabed erosion or loss and basal erosion beneath turbidites. Neither of these approaches achieves a modern seabed age when applying the commonly used regional marine 14C reservoir age of 800 years (marine reservoir correction ΔR = 400 years). Rather, the top of the core appears to be 400 years in the future. A younger marine reservoir age of 400 years (ΔR = 0 years) brings the top to the present and produces better correlations with the nearby Effingham Inlet paleo-earthquake chronology based only on terrestrial carbon requiring no reservoir correction. The high-resolution dating and facies analysis of Slipstream Slump in this isolated slope basin setting demonstrates that this is also a useful type of sedimentary target for sampling the paleoseismic record in addition to the more studied turbidites from submarine canyon and channel systems. The first 10 turbidites at Slipstream Slump were deposited between 10.8 and 6.6 ka BP, after which the system became sediment starved and only two more turbidites were deposited. The recurrence interval for the inferred frequent early Holocene megathrust earthquakes is 460 ± 140 years, compatible with other estimates of paleoseismic megathrust earthquake occurrence rates along the subduction zone.
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BAUDIN, FRANÇOIS, CHRISTOPHE RABOUILLE et BERNARD DENNIELOU. « Routing of terrestrial organic matter from the Congo River to the ultimate sink in the abyss : a mass balance approach (André Dumont medallist lecture 2017) ». Geologica Belgica 23, no 1-2 (9 avril 2020) : xx. http://dx.doi.org/10.20341/gb.2020.004.
Texte intégralRésumé :
We address the role of the Congo River sediment dispersal in exporting and trapping organic carbon into deep offshore sediments. Of particular interest is the Congo submarine canyon, which constitutes a permanent link between the terrestrial sediment sources and the marine sink. The Congo River delivers an annual sediment load of ~40 Tg (including 2 Tg of C) that feed a mud-rich turbidite system. Previous estimates of carbon storage capacity in the Congo turbidite system suggest that the terminal lobe complex accounts for ~12% of the surface area of the active turbidite system and accumulates ~18% of the annual input of terrestrial particulate organic carbon exiting the Congo River. In this paper, we extend the approach to the whole active turbidite depositional system by calculating an average burial of terrestrial organic matter in the different environments: canyon, channel, and levees. We estimate that between 33 and 69% of terrestrial carbon exported by the Congo River is ultimately trapped in the different parts of turbidite system and we evaluate their relative efficiency using a source to sink approach. Our carbon budget approach, which consider annual river discharge versus offshore centennial accumulation rates, indicates that about half of the total particulate organic matter delivered yearly by the Congo River watershed escapes the study area or is not correctly estimated by our deep offshore dataset and calculations.
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Mignard, Salomé, Thierry Mulder, Philippe Martinez et Thierry Garlan. « The Ogooue Fan (offshore Gabon) : a modern example of deep-sea fan on a complex slope profile ». Solid Earth 10, no 3 (17 juin 2019) : 851–69. http://dx.doi.org/10.5194/se-10-851-2019.
Texte intégralRésumé :
Abstract. The effects of changes in slope gradient on deposition processes and architecture have been investigated in different deep-sea systems both in modern and ancient environments. However, the impact of subtle gradient changes (< 0.3∘) on sedimentary processes along deep-sea fans still needs to be clarified. The Ogooue Fan, located in the northeastern part of the Gulf of Guinea, extends over more than 550 km westwards of the Gabonese shelf and passes through the Cameroon volcanic line. Here, we present the first study of acoustic data (multibeam echosounder and 3.5 kHz, very high-resolution seismic data) and piston cores covering the deep-sea part of this West African system. This study documents the architecture and sedimentary facies distribution along the fan. Detailed mapping of near-seafloor seismic-reflection data reveals the influence of subtle slope gradient changes (< 0.2∘) along the fan morphology. The overall system corresponds to a well-developed deep-sea fan, fed by the Ogooue River sedimentary load, with tributary canyons, distributary channel–levee complexes and lobe elements. However, variations in the slope gradient due to inherited salt-related structures and the presence of several seamounts, including volcanic islands, result in a topographically complex slope profile including several ramps and steps. In particular, turbidity currents derived from the Gabonese shelf deposit cross several interconnected intra-slope basins located on the low gradient segments of the margin (< 0.3∘). On a higher gradient segment of the slope (0.6∘), a large mid-system valley developed connecting an intermediate sedimentary basin to the more distal lobe area. Distribution and thickness of turbidite sands is highly variable along the system. However, turbidite sands are preferentially deposited on the floor of the channel and the most proximal depositional areas. Core description indicates that the upper parts of the turbidity flows, mainly composed of fine-grained sediments, are found in the most distal depocenters.
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Avseth, P., T. Mukerji, A. Jørstad, G. Mavko et T. Veggeland. « Seismic reservoir mapping from 3‐D AVO in a North Sea turbidite system ». GEOPHYSICS 66, no 4 (juillet 2001) : 1157–76. http://dx.doi.org/10.1190/1.1487063.
Texte intégralRésumé :
We present a methodology for estimating uncertainties and mapping probabilities of occurrence of different lithofacies and pore fluids from seismic amplitudes, and apply it to a North Sea turbidite system. The methodology combines well log facies analysis, statistical rock physics, and prestack seismic inversion. The probability maps can be used as input data in exploration risk assessment and as constraints in reservoir modeling and performance forecasting. First, we define seismic‐scale sedimentary units which we refer to as seismic lithofacies. These facies represent populations of data (clusters) that have characteristic geologic and seismic properties. In the North Sea field presented in this paper, we find that unconsolidated thick‐bedded clean sands with water, plane laminated thick‐bedded sands with oil, and pure shales have very similar acoustic impedance distributions. However, the [Formula: see text] ratio helps resolve these ambiguities. We establish a statistically representative training database by identifying seismic lithofacies from thin sections, cores, and well log data for a type well. This procedure is guided by diagnostic rock physics modeling. Based on the training data, we perform multivariate classification of data from other wells in the area. From the classification results, we can create cumulative distribution functions of seismic properties for each facies. Pore fluid variations are accounted for by applying the Biot‐Gassmann theory. Next, we conduct amplitude‐variation‐with‐offset (AVO) analysis to predict seismic lithofacies from seismic data. We assess uncertainties in AVO responses related to the inherent natural variability of each seismic lithofacies using a Monte Carlo technique. Based on the Monte Carlo simulation, we generate bivariate probability density functions (pdfs) of zero‐offset reflectivity [R(0)] versus AVO gradient (G) for different facies combinations. By combining R(0) and G values estimated from 2‐D and 3‐D seismic data with the bivariate pdfs estimated from well logs, we use both discriminant analysis and Bayesian classification to predict lithofacies and pore fluids from seismic amplitudes. The final results are spatial maps of the most likely facies and pore fluids, and their occurrence probabilities. These maps show that the studied turbidite system is a point‐sourced submarine fan in which thick‐bedded clean sands are present in the feeder‐channel and in the lobe channels, interbedded sands and shales in marginal areas of the system, and shales outside the margins of the turbidite fan. Oil is most likely present in the central lobe channel and in parts of the feeder channel.
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Fournier, Léa, Kelly Fauquembergue, Sébastien Zaragosi, Coralie Zorzi, Bruno Malaizé, Franck Bassinot, Ronan Joussain, Christophe Colin, Eva Moreno et François Leparmentier. « The Bengal fan : External controls on the Holocene Active Channel turbidite activity ». Holocene 27, no 6 (novembre 2016) : 900–913. http://dx.doi.org/10.1177/0959683616675938.
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McHargue, T., M. J. Pyrcz, M. D. Sullivan, J. D. Clark, A. Fildani, B. W. Romans, J. A. Covault, M. Levy, H. W. Posamentier et N. J. Drinkwater. « Architecture of turbidite channel systems on the continental slope : Patterns and predictions ». Marine and Petroleum Geology 28, no 3 (mars 2011) : 728–43. http://dx.doi.org/10.1016/j.marpetgeo.2010.07.008.
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Normark, William R., David J. W. Piper, Henry Posamentier, Carlos Pirmez et Sébastien Migeon. « Variability in form and growth of sediment waves on turbidite channel levees ». Marine Geology 192, no 1-3 (décembre 2002) : 23–58. http://dx.doi.org/10.1016/s0025-3227(02)00548-0.
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Hans Nelson, C., John E. Damuth et Hilary Clement Olson. « Late Pleistocene Bryant Canyon turbidite system : Implications for Gulf of Mexico minibasin petroleum systems ». Interpretation 6, no 2 (1 mai 2018) : SD89—SD114. http://dx.doi.org/10.1190/int-2017-0150.1.
Texte intégralRésumé :
The western ancestral Mississippi shelf-margin delta fed the Bryant Canyon turbidite system in the intraslope basin province of the northwestern Gulf of Mexico (GOM) during the penultimate glacial lowstand of sea level (130–160 year BP). The Bryant Canyon links a chain of 15 fill-and-spill minibasins on the continental slope. On the upper and lower continental slopes, minibasins are narrow (1–3 km), elongate (3–6 km), and follow salt ridges. On the middle slope, minibasins are larger (8–15 km) semicircular basins. Three main depositional facies are recognized based on seismic-facies interpretation: (1) ponded turbidites (T), (2) mass-transport deposits (MTDs), and (3) bypass channelized turbidites (C). Thick, intrabasinal, muddy MTD wedges sourced from high-relief internal walls of the minibasins alternate with and frequently cap externally derived deposits. Tabular extrabasinal MTD deposits originated from shelf-margin delta or canyon-wall failures upslope. The T and MTD facies deposits each make up approximately 40% of basin fill, and the C facies deposits comprise approximately 20%. The T facies deposits form perched lobes at canyon inlets into basins and ponded units on distal sides of basins. Channels in the C facies are similar in width (500–2000 m) and relief (20–100 ms) to channels in productive GOM subsurface minibasins. Syntectonic activity of salt diapirs typically began midway through filling of Bryant Canyon minibasins and then preferentially uplifted northern portions of basin deposits. Local salt-tectonic activity caused greater basin relief and thicker capping MTDs than in subsurface minibasins to the west (e.g., Brazos-Trinity Basin IV) or east (e.g., Mississippi Canyon). Bryant Canyon minibasins provide excellent modern analogs for subsurface Miocene to Pleistocene GOM chains of minibasins because of similar scales and depositional facies. The youngest Bryant T facies deposits and their overlying incised, thick, channel deposits contain the most sand-prone facies and suggest the best potential for petroleum reservoirs in subsurface minibasins.
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Vrbanac, Boris. « Facies and Facies Architecture of the Ivanić Grad Formation (Upper Pannonian) - Sava Depression, NW Croatia ». Geologia Croatica 55, no 1 (2002) : 57–77. http://dx.doi.org/10.4154/gc.2002.06.
Texte intégralRésumé :
Four facies were distinguished within the Ivanić Grad Formation of the Sava Depression: massive marl facies (F1), thick-bedded to massive sandstone facies (F2), thin-bedded sandstone facies (F3) and thin bedded sandstone, siltite and marl facies (F4). Interpretation of the depositional mechanisms confirmed the presence of two basic sedimentary processes. Hemipelagic deposits are represented by fine grained detritus. The lithification of these produced a massive marl(facies - F1). Sand detritus was transported into the depression by turbidite currents (facies - F2- F4), and formed a narrow elongated sedimentary body. By comparing the facies defined on the basis of core samples, the spontaneous-potential curve (SP) and the resistivity curve (Ra) of identical intervals, four facies associations were defined on well logdiagrams: channel filling (FA), depositional lobe (FB), lateral and distal turbidites (FC) and massive marls (FD).
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Smith, James A., Claus-Dieter Hillenbrand, Robert D. Larter, Alastair G. C. Graham et Gerhard Kuhn. « The sediment infill of subglacial meltwater channels on the West Antarctic continental shelf ». Quaternary Research 71, no 2 (mars 2009) : 190–200. http://dx.doi.org/10.1016/j.yqres.2008.11.005.
Texte intégralRésumé :
AbstractSubglacial meltwater plays a significant yet poorly understood role in the dynamics of the Antarctic ice sheets. Here we present new swath bathymetry from the western Amundsen Sea Embayment, West Antarctica, showing meltwater channels eroded into acoustic basement. Their morphological characteristics and size are consistent with incision by subglacial meltwater. To understand how and when these channels formed we have investigated the infill of three channels. Diamictons deposited beneath or proximal to an expanded grounded West Antarctic Ice Sheet are present in two of the channels and these are overlain by glaciomarine sediments deposited after deglaciation. The sediment core from the third channel recovered a turbidite sequence also deposited after the last deglaciation. The presence of deformation till at one core site and the absence of typical meltwater deposits (e.g., sorted sands and gravels) in all three cores suggest that channel incision pre-dates overriding by fast flowing grounded ice during the last glacial period. Given the overall scale of the channels and their incision into bedrock, it is likely that the channels formed over multiple glaciations, possibly since the Miocene, and have been reoccupied on several occasions. This also implies that the channels have survived numerous advances and retreats of grounded ice.
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Babonneau, N., B. Savoye, M. Cremer et M. Bez. « Sedimentary Architecture in Meanders of a Submarine Channel : Detailed Study of the Present Congo Turbidite Channel (Zaiango Project) ». Journal of Sedimentary Research 80, no 10 (1 octobre 2010) : 852–66. http://dx.doi.org/10.2110/jsr.2010.078.
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Alpak, Faruk O., Mark D. Barton et Stephen J. Naruk. « The impact of fine-scale turbidite channel architecture on deep-water reservoir performance ». AAPG Bulletin 97, no 2 (février 2013) : 251–84. http://dx.doi.org/10.1306/04021211067.
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Fierens, Ruth, Laurence Droz, Samuel Toucanne, François Raisson, Gwenael Jouet, Nathalie Babonneau, Elda Miramontes, Steven Landurain et Stephan J. Jorry. « Late Quaternary geomorphology and sedimentary processes in the Zambezi turbidite system (Mozambique Channel) ». Geomorphology 334 (juin 2019) : 1–28. http://dx.doi.org/10.1016/j.geomorph.2019.02.033.
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Gong, Chenglin, Kun Qi, Yuan Ma, Dongwei Li, Nan Feng et Hongxiang Xu. « Tight coupling between the cyclicity of deep-water systems and rising-then-flat shelf-edge pairs along the submarine segment of the Qiongdongnan sediment-routing system ». Journal of Sedimentary Research 89, no 10 (28 octobre 2019) : 956–75. http://dx.doi.org/10.2110/jsr.2019.47.
Texte intégralRésumé :
ABSTRACT On the basis of shelf-edge (SE) trajectory analysis, the present study demonstrates the tight coupling between the cyclicity of deep-water systems and contemporaneous SE trajectories with a paired rising-then-flat trajectory tendency (termed “SE pairs”) along the submarine segment of the mid-Pleistocene Qiongdongnan sediment-routing system, contributing to a better understanding of how to predict internal architecture and stacking patterns of deep-water systems. At the outlying deep-water reaches of the mid-Pleistocene Qiongdongnan sediment-routing system, Qiongdongnan deep-water systems are shown to have grown in a cyclic fashion that is stratigraphically manifested as the underlying mass-transport deposits (MTDs) systematically capped by submarine channels or sheet-like turbidites (i.e., MTD-channel and MTD-turbidite cycles, respectively). At the SE staging areas of the mid-Pleistocene Qiongdongnan sediment-routing system, Qiongdongnan shelf edges (SEs) have grown in a paired rising-then-flat fashion. The lower stratigraphic fill level of Qiongdongnan deep-water sedimentation cycles correlates to rising SE trajectories, during which the far shoreline to SE proximity (i.e., the long shoreline to SE distance of tens of kilometers) coupled to positive shelf accommodation [represented by positive SE trajectory angles () of 4.38° to 10.45°] most likely promoted passive sediment-transport agents and resultant MTDs. The upper stratigraphic fill level of mid-Pleistocene Qiongdongnan sedimentation cycles, in contrast, corresponds to flat SE trajectories, during which the close shoreline to SE proximity (i.e., the short shoreline to SE distance of < 5 km) coupled to negative shelf accommodation (represented by of –0.17° to –1.32°), in contrast, favored active sediment-transport agents and resultant submarine channels or sheet-like turbidites.
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Konar, Shubhodip, Pinaki Majumdar, Prem Kumar, Chandan Saha, Ajoy Krishna Bora, Vachaspati Kothari et Pranay Shankar. « Capturing uncertainties through scenario-based integrated static reservoir modeling of lacustrine turbidites in the Barmer Basin, India ». Interpretation 6, no 3 (1 août 2018) : T667—T688. http://dx.doi.org/10.1190/int-2017-0144.1.
Texte intégralRésumé :
Most static modeling workflows deal with stochastic simulations of the uncertain subsurface parameters on a base case model, although recent studies highlighted usefulness of discrete deterministic multiple geological scenario-based modeling. This paper illustrates the benefits of capturing the principal geological uncertainties through discrete subsurface scenarios, through a case study from the Vijaya and Vandana (V&V) field, Barmer Basin, northwest India. The 12 exploration and appraisal wells have established seven stratigraphically trapped oil pools with the maximum resources confined in the V&V mounds, consisting of turbidite sandstones and conglomerates in a shale background, inferred to be deposited in a deep lacustrine environment. Hydraulic fracturing of these sandstones resulted in significant production increase. Detailed subsurface analysis suggests that the V&V mounds consist of two channel complexes represented by a laterally migrating network of turbidite channels with a maximum thickness of 4–5 m for individual sandstones. Multiattribute seismic studies indicate that delineation of these channel sands, controlled mainly by the channel geometries, cannot be resolved by seismic signature/attribute studies alone, which necessitates the iteration of the facies model into five different scenarios. Each of the facies scenarios is further iterated with other key uncertain input parameters for STOIIP calculation (namely saturation, porosity, contact, etc.) to result in 50 deterministic static realizations that capture the wide uncertainty range of in-place volumes, through a cumulative distribution function plot. In the absence of a defined concept, our model highlights the importance of deterministic depiction of subsurface concepts (geologic, geophysical, petrophysical, and dynamic) through a scenario-based approach. This workflow captures a wide range of various high-impact uncertainties in an integrated manner and links discrete, deterministic, scenario-based outcomes to probabilistic reporting. This will help in the decision-making process by linking the model outcome with long-term well testing and ultimately the concept underlying the development plan.
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Alpak, Faruk O., James W. Jennings, Paul Gelderblom, Chaohui Chen, Guohua Gao et Kuifu Du. « A Direct Overparameterize and Optimize Method for Stratigraphically Consistent Assisted History Matching of Object-Based Geomodels : Algorithm and Field Application ». SPE Journal 22, no 04 (6 mars 2017) : 1280–95. http://dx.doi.org/10.2118/181269-pa.
Texte intégralRésumé :
Summary Object-based static models are typically constructed for stratigraphically complex reservoirs. In this approach, the stratigraphic architecture is represented by use of distinct objects with specific geometric attributes and petrophysical characteristics. It is a major challenge to condition such models to production data while simultaneously maintaining the geologic realism and static conditioning. A novel work flow is developed for the assisted history matching (AHM) of object-based geomodels where the uncertain object locations and attributes are directly modified without resorting to (post-geomodeling) reparameterization techniques. It contains an object-modeling algorithm for channels and levees that provides direct access to the preraster geomodeling parameters for individual object locations and attributes. These parameters are gradually modified subject to physical constraints to achieve a history match. A fully integrated protocol is used in this process that automatically couples the static modeling algorithm with the reservoir simulator. The resulting work flow is moderated by a massively parallel and highly efficient iterative data-integration algorithm. In the AHM work flow, static and dynamic conditioning operations are respectively driven by separate objective functions and are performed at the iteration level in a sequential fashion. The static-conditioning step may add and remove objects in the geomodel, which changes the number of active AHM parameters over the course of the iterative search. The work flow handles such operations with minimal impact on the robustness of the search. A potential application of the direct AHM work flow for object-based geomodels is the identification of locations and attributes of channels in deepwater turbidite reservoirs, where the channels are typically below the resolution of the seismic data; the well spacing is typically larger than the characteristic object dimension, yet the production data exhibit strong sensitivity to channel connectivity. The concept of gradually adjusting the channel locations with the information in the production data (while maintaining static conditioning) is demonstrated on a real data set for a deepwater channelized-turbidite reservoir. The models proposed by the new AHM work flow not only improve the difficult-to-history-match injected-gas-breakthrough profiles but also provide geologically based explanations for them, taking into account the channel connectivity. The proposed AHM work flow ensures consistency across static and dynamic models by integrating multidisciplinary data with an easily auditable and replicable capability.
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Strecker, Uwe, Paola Vera de Newton et Maggie Smith. « From qualitative to quantitative interpretation : An interpreter’s guide to fluid prediction in Pliocene to Turonian deepwater turbidites from West Africa to Asia Pacific ». Interpretation 2, no 1 (1 février 2014) : SA127—SA140. http://dx.doi.org/10.1190/int-2013-0106.1.
Texte intégralRésumé :
To mitigate exploration risk in deepwater settings, subsurface analysis increasingly has to rely on integration of qualitative with quantitative techniques. To predict pay in turbidite sandstones, proven statistical and analytical methods can routinely be run on well and seismic inversion data. However, quantitative interpretation (QI) should begin with a responsible audit of available well logs and seismic data, succeeded by data conditioning, proceeding with quality control, and placing elastic attribute responses within their geologic context. To address these issues, we evaluate geologic controls on porosity change as manifested by overpressure and compaction on calibration and analysis of elastic attributes. Following calibration of seismic inversion data, we provide tutorial-style interpretations of deepwater clastic reservoirs from the Gulf of Guinea, West Africa, to the Sabah trough, Borneo. Case study examples offer interpreters the potential to use workflows surrounding data mining in exploration or during field development. In our first example, a comparison of univariate statistics run on compressional- and shear-wave impedances and Poisson’s ratio is introduced to potentially data mine 3D seismic over turbidite fairways. Joint interpretation of P-wave and S-wave impedances is combined with innovative uses of bivariate statistical analysis for anomaly detection. Additionally, the geologic rationale of interpreting elastic relationships of calibrated attributes, such as Lambda Rho and Mu Rho, is discussed on the seismic scale of a single reservoir layer using a combination of statistical methods and rock physics. Here, qualitative interpretation, via application of principles from seismic stratigraphy and seismic geomorphology, ultimately unlocks ambiguity in rock-physics-driven, quantitative lithology determination, guiding application of QI routines toward correctly predicting the prevailing fluid type. Elastic calibration permits seismic lithofacies classification of Cretaceous turbidite sandstones deposited as middle to lower slope channels canyon-fill and basin-floor channel complexes.
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Chopra, Satinder, Ritesh Kumar Sharma, Kurt J. Marfurt, Heather Bedle et Sumit Verma. « Attempts at seismic characterization of a deepwater turbidite channel in Taranaki Basin, New Zealand ». First Break 40, no 10 (1 octobre 2022) : 27–39. http://dx.doi.org/10.3997/1365-2397.fb2022080.
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Rizal, Yan, Wahyu Dwijo Santoso, Alfend Rudyawan, Romy Ari Setiaji et Eko Bayu Purwasatriya. « Turbidite Fasies of Lower Penosogan Formation in Karanggayam Area, Kebumen, Indonesia ». Modern Applied Science 12, no 6 (30 mai 2018) : 124. http://dx.doi.org/10.5539/mas.v12n6p124.
Texte intégralRésumé :
A continuous clastic sedimentary rock outcrop in the Karanggayam Area, Kebumen represents the complete deep marine fan facies of the Middle Miocene Lower Penosogan Formation. Lithology association and vertical succession were observed from a 63 meters detailed measured section along the Karanggayam River. This study aims to identify and classify the turbidite succession as well as the depositional environment of the formation within the North Serayu Basin, Central Java. From the bottom to top the Lower Penosogan Formation is divided into: A2, B2, C2, D2 and F2 facies which represents basin plain, overbank (levee and distal levee), crevasse splay, channel-fill and frontal splay facies respectively. Changes in the depositional environment are interpreted to be influenced by the dynamic changes in morphology and global climate change caused by underwater volcanic activity as a result of Middle Miocene tectonic activity.
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Tek, Daniel E., Miquel Poyatos-Moré, Marco Patacci, Adam D. McArthur, Luca Colombera, Timothy M. Cullen et William D. McCaffrey. « Syndepositional tectonics and mass-transport deposits control channelized, bathymetrically complex deep-water systems (Aínsa depocenter, Spain) ». Journal of Sedimentary Research 90, no 7 (15 juillet 2020) : 729–62. http://dx.doi.org/10.2110/jsr.2020.38.
Texte intégralRésumé :
ABSTRACT The inception and evolution of channels in deep-water systems is controlled by the axial gradient and lateral confinement experienced by their formative flows. These parameters are often shaped by the action of tectonic structures and/or the emplacement of mass-transport deposits (MTDs). The Arro turbidite system (Aínsa depocenter, Spanish Pyrenees) is an ancient example of a deep-water channelized system from a bathymetrically complex basin, deposited in an active tectonic setting. Sedimentologic fieldwork and geologic mapping of the Arro system has been undertaken to provide context for a detailed study of three of the best-exposed outcrops: Sierra de Soto Gully, Barranco de la Caxigosa, and Muro de Bellos. These locations exemplify the role of confinement in controlling the facies and architecture in the system. Sedimentologic characterization of the deposits has allowed the identification of fifteen facies and eight facies associations; these form a continuum and are non-unique to any depositional environment. However, architectural characterization allowed the grouping of facies associations into four depositional elements: i) weakly confined, increasing-to-decreasing energy deposits; ii) progradational, weakly confined to overbank deposits; iii) alternations of MTDs and turbidites; iv) channel fills. Different styles of channel architecture are observed. In Barranco de la Caxigosa, a master surface which was cut and subsequently filled hosts three channel stories with erosional bases; channelization was enhanced by quasi-instantaneous imposition of lateral confinement by the emplacement of MTDs. In Muro de Bellos, the inception of partially levee-confined channel stories was enhanced by progressive narrowing of the depositional fairway by tectonic structures, which also controlled their migration. Results of this study suggest that deep-water channelization in active tectonic settings may be enhanced or hindered due to: 1) flow interaction with MTD-margin topography or; 2) MTD-top topography; 3) differential compaction of MTDs and/or sediment being loaded into MTDs; 4) formation of megascours by erosive MTDs; 5) basin-floor topography being reset by MTDs. Therefore, the Arro system can be used as an analog for ancient subsurface or outcrop of channelized deposits in bathymetrically complex basins, or as an ancient record of deposits left by flow types observed in modern confined systems.
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O’Halloran, Gerry, Chris Hurren et Tim O’Hara. « Seismic stratigraphic relationships within a lowstand reservoir system : examples from the Barrow Group, Southern Exmouth Sub-Basin, NW Australia ». APPEA Journal 54, no 2 (2014) : 1. http://dx.doi.org/10.1071/aj13004.
Texte intégralRésumé :
The Late Jurassic–Early Cretaceous Eskdale and Macedon members of the lower Barrow Group comprise some of the main oil-bearing reservoirs in the Exmouth Sub-basin. These high quality sandstones form the reservoirs in the Stybarrow and Eskdale oil fields. Understanding the architecture of these deepwater successions is important in both exploration and development projects. This paper documents detailed stratigraphic relationships and depositional geometries as defined on high quality seismic data sets and associated well data. An initial phase of lowstand deposition (Eskdale Member) is recorded by the development of two main canyon systems; the Eskdale and slightly younger Laverda canyons. These systems are remarkably well imaged on 3D seismic data, allowing for detailed definition of channel morphology and associated fill and spill facies. Channel complexes are up to 1 km-wide and 100 m-deep, and display evidence for multiple phases of erosion and in-channel aggradation. Overbank/spill facies are also identifiable, including crevasse lateral lobes and ‘chute’ channels. These canyon systems fed contemporaneous downdip basin floor fans that display a variety of classical fan morphologies and depositional elements including terminal lobes, fan pinchout edges, distributary channel systems and localised outflow facies. The distribution and morphology of the Eskdale and Laverda canyons and associated fan intervals can be related to topographic gradient changes within the basin (i.e. from shelf to slope to basin floor). These topographic changes are in turn a response to regional tectonism, in particular active rifting along basin margins. An ensuing phase of less confined, shelf-slope turbidite deposition (Macedon Member) records late-stage lowstand processes. Detailed well and seismic control from the Stybarrow Field and surrounding areas has identified multicyclic sands recording deposition of stacked turbidite lobes. These lobe complexes are more laterally continuous than the canyon facies and are comprised of amalgamated sheet sands and lower-relief channel sands, and are generally between 15–25 m thick. In the greater Stybarrow area the original lobate geometries have been subsequently modified by a phase of late-stage erosion. Outcrop analogues for the Macedon Member can be seen in the lobe complexes from the Tanqua Fan intervals of the Karoo Basin, which are similar in both scale and morphology. These lobe complexes extend laterally for tens of kilometres with constituent individual lobes often displaying evidence for compensational depositional processes. This paper was originally published in the Proceedings of the West Australian Basins Symposium 2013, which was held from 18–21 August 2013 in Perth, Australia.