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Donald R Lowe - One of the best experts on this subject based on the ideXlab platform.
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facies architecture of a submarine fan channel levee complex the juniper ridge Conglomerate coalinga california
Sedimentology, 2002Co-Authors: Thomas A Hickson, Donald R LoweAbstract:The Upper Cretaceous Juniper Ridge Conglomerate (JRC) near Coalinga, California, provides a rare, high-quality exposure of a submarine channel to overbank transition. The facies architecture of the JRC comprises a thick, predominantly mudstone sequence overlain by a channellized Conglomerate package. Conglomeratic bounding surfaces truncate successions of interbedded turbiditic sandstones and mudstones both vertically and laterally. Thick-bedded, massive sandstones are interbedded with Conglomerates. Facies architecture, palaeocurrent indicators, slump features, sandstone percentages and sandstone bed thickness trends lead to the interpretation that these elements comprise channel and overbank facies. A vertical sequence with Conglomerate at the base, followed by thick-bedded sandstone, and capped by interbedded turbiditic sandstone and mudstone form a fining-upward lithofacies association that is interpreted as a single channel-fill/overbank system. Three similar lithofacies associations can be related to autocyclic processes of thalweg migration and submarine fan aggradation or to allocyclically driven changes in sediment calibre.
Miland Gas Co. - One of the best experts on this subject based on the ideXlab platform.
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Factors controlling the distribution of reservoir quality in the Pennsylvanian bend Conglomerate fan-delta system
AAPG Bulletin, 1991Co-Authors: R.g. Loucks, Plano Gas Co., J. Troschinetz, Miland Gas Co.Abstract:Chert Conglomerates, and associated sediments, of the Bend Conglomerate in Taylor Draw field, Upton Co., Texas, were deposited in a series of fan deltas that prograded into an open-marine system. The distribution of reservoir quality in these deposits is facies controlled. Permeabilities range from near zero to 30,000 md. Low-permeability Conglomerates contain either a mud matrix or abundant calcite fossil fragments. The calcite grains serve as nucleation sites for calcite cementation and, through dissolution, as a source of calcite cement. High-permeability, sandy (chert and quartz) Conglomerates have no mud matrix or calcite grains. Some of them are cemented with a thin rim of chalcedony, while others have no cement and show strong pressure solution at grain contacts. They are commonly friable and are recovered as loose gravels in the core barrel. The mineralogy of matrix gains is related to the distribution of the depositional facies within the fan delta. The low-permeability Conglomerates were deposited in the subaerial to subaqueous distal fan-delta complex where calcareous marine organisms or mud were mixed with the Conglomerate. The high-permeability Conglomerates were deposited as thick channel-gravels in the subaerial proximal and mid-fan sections of the fan deltas. Depositional facies within the fan-delta complex controlled themore » distribution of calcite grains in the matrix and hence reservoir quality. The fossiliferous Conglomerates became tightly cemented with calcite during burial, whereas the nonfossiliferous Conglomerates remained permeable. Facies maps of the fan-delta complex therefore can be used to delineate high-permeability conglomeratic reservoirs.« less
Luo Hui - One of the best experts on this subject based on the ideXlab platform.
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Conglomerates record the tectonic evolution of the Yarlung-Tsangpo suture zone in southern Tibet
Geological Society London Special Publications, 2004Co-Authors: Aileen M. Davis, Jonathan C. Aitchison, Badengzhu, Luo HuiAbstract:The histories of individual conglomeratic units along the Yarlung-Tsangpo (River) suture zone in southern Tibet reflect significant phases in the Mesozoic to Cenozoic tectonic evolution of this area. Several temporally distinct Conglomerate units are recognized along the suture, and their detailed examination permits analysis of the collision between India and Asia. Upper Jurassic to Lower Cretaceous Conglomerates crop out within the Sangri Group along the southern Lhasa terrane. They are dominated by limestone and andesitic volcanic cobbles derived entirely from the Lhasa terrane. These rocks have experienced amphibolite facies metamorphism, and exhibit a strong penetrative regional foliation. Thick successions of the Palaeocene Liuqu Conglomerate crop out within the suture from Xigaze to Lhaze. They contain detritus sourced from intra-oceanic terranes associated with the suture zone, as well as clasts of Indian affinity, while Lhasa and Xigaze terrane-derived material is notably absent. These Conglomerates record an early suture zone event prior to India-Asia collision. Uppermost Oligocene to Lower Miocene 'Gangrinboche facies' Conglomerates crop out on the southern edge of the Lhasa terrane along the length of the suture. Several correlative units within this facies exhibit broadly similar stratigraphic histories. A basal depositional contact upon an eroded Lhasa terrane surface is ubiquitous with initial clast derivation from the north. Up-section, the first arrival of coarse-grained, suture-zone and India-derived clasts, is abrupt. These southerly derived clasts predominate by the top of most sections. An a really restricted succession of gently dipping Late Neogene ultramafic breccias unconformably overlies folded Liuqu Conglomerate near Quanggong. Other Neogene sediments are extensive west of Mount Kailas. Deposition of coarse clastic sediments is presently continuing along the length of the Yarlung Tsangpo. Discrimination and detailed investigation of each of these units will improve our understanding of the evolution of the India-Asia collision.
Thomas A Hickson - One of the best experts on this subject based on the ideXlab platform.
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facies architecture of a submarine fan channel levee complex the juniper ridge Conglomerate coalinga california
Sedimentology, 2002Co-Authors: Thomas A Hickson, Donald R LoweAbstract:The Upper Cretaceous Juniper Ridge Conglomerate (JRC) near Coalinga, California, provides a rare, high-quality exposure of a submarine channel to overbank transition. The facies architecture of the JRC comprises a thick, predominantly mudstone sequence overlain by a channellized Conglomerate package. Conglomeratic bounding surfaces truncate successions of interbedded turbiditic sandstones and mudstones both vertically and laterally. Thick-bedded, massive sandstones are interbedded with Conglomerates. Facies architecture, palaeocurrent indicators, slump features, sandstone percentages and sandstone bed thickness trends lead to the interpretation that these elements comprise channel and overbank facies. A vertical sequence with Conglomerate at the base, followed by thick-bedded sandstone, and capped by interbedded turbiditic sandstone and mudstone form a fining-upward lithofacies association that is interpreted as a single channel-fill/overbank system. Three similar lithofacies associations can be related to autocyclic processes of thalweg migration and submarine fan aggradation or to allocyclically driven changes in sediment calibre.
A.e. Holmes - One of the best experts on this subject based on the ideXlab platform.
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Late Devonian carbonate-Conglomerate association in the Canning basin, Western Australia
AAPG Bulletin, 1991Co-Authors: A.e. HolmesAbstract:Siliciclastic Conglomerates of Late Devonian to Carboniferous age crop out discontinuously along the northern margin of the Canning basin in Western Australia, where they are associated with a classic example of reefal carbonate rocks. An understanding of these deposits is relevant to the timing of extension in the basin, uplift of the adjacent Kimberley block, and to the interpretation of the sequence stratigraphy of the carbonates. The Conglomerates indicate that the Kimberley block was high-standing, even though most normal faulting appears to have ceased by Late Devonian time, and provided a continuous source of siliclastic material. The carbonate-Conglomerate relationships were studied in detail at two localities, with brief visits to several other sections to provide a regional context. A sequence boundary of late Frasnian age is exposed at several localities. Incised valleys with 10 m relief (e.g. Van Emmerick and Mt. Elma) and onlapping relationships (e.g. Stony Creek, Van Emmerick) provide strong evidence for a type 1 boundary that likely formed during a eustatic base-level drop (cf., Devonian carbonates of Canada). The recognition of several intervals of siliciclastic Conglomerate influx in the Canning basin is important because it suggests the presence of distal lowstand sandstone reservoirs that may represent potential more » petroleum targets. « less