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Showing 1 to 20 of 30 for “"Middle Cambrian"”.
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Sedimentology and diagenesis of Lower to Middle Cambrian carbonate platform, Shady Dolomite, Virginia
Drill cores through the Lower to Middle Cambrian Shady Dolomite carbonate platform (600 to 1200 m thick) in the Austinville, Virginia, region allow the evolution of the carbonate platform from a gently sloping ramp, to a high relief, rimmed shelf to be documented. The Shady Dolomite forms the …
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Stratigraphy, Sedimentology, and Ichnology of the Middle Cambrian to Lower Ordovician Deposits in Subsurface Western Canada
… decade, the economic importance of the preserved Cambrian-Ordovician succession in subsurface Alberta and Saskatchewan has increased considerably, mainly due to the development of geothermal, carbon sequestration, and helium exploration and extraction projects. Despite this, the construction of a …
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Middle Cambrian linguliformean brachiopods of the Pika and Sullivan formations, southern Canadian Rocky Mountains, Alberta, Canada
… were collected and described from the middle Cambrian Pika and Sullivan formations in the southern Canadian Rocky Mountains. These formations consist of coarse-grained grainstone interbedded with lime mudstones and siltstones in a storm-influenced, distal offshore setting. Grainstone …
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Stratigraphy And Depositional Environments Of Lower And Middle Cambrian Strata In The Lake Mead Region, Southern Nevada And Northwestern Arizona
… systems revealed within the Lower to Middle Cambrian Tapeats Sandstone-Pioche Shale-Lyndon Limestone-Chisholm Shale succession were studied between the easternmost limit of Cretaceous overthrusting in southern Nevada and the western edge of the Colorado Plateau in northwestern Arizona. …
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Geology of the Flathead Formation (Middle Cambrian) on the perimeter of the Bighorn Basin, Beartooth Mountains, and Little Belt Mountains in Wyoming and Montana
… Formation, which is 4 to 60 metres thick in the middle and northern Rocky Mountains of Wyoming and Montana, contains cross-bedded and parallel-bedded, quartz sandstone. The formation contains marginal-marine and shallow-marine sediment that was deposited unconformably on Precambrian crystalline …
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Structural geology of the Christiansburg area, Montgomery County, Virginia
… by sedimentary rocks ranging in age from Middle Cambrian to Middle Ordovician. Post-Ordovician strata have been eliminated by thrusting and erosion. From south to north the rocks belong to five fault blocks: the Max Meadows, Pulaski, Saltville, Salem, and Catawba blocks. The Max Meadows …
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Geology of the Spruce Run Mountain area, Giles County, Virginia
… the Spruce Run Mountain area range in age from Middle Cambrian to Lower Devonian. All the rocks are sedimentary rocks deposited in a marine environment and have an aggregate thickness of approximately 6,500 feet. An important disconformity separates rocks of Lower Ordovician age from those of …
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Paleontology and stratigraphy of the Shady Formation near Austinville, Virginia
… the Shady Formation is entirely of Early Cambrian age, lies stratigraphically above the Erwin Quartzite and stratigraphically below the Rome Formation, and includes the Patterson Member at the base, the Austinville Member, and the Ivanhoe Member at the top. Southeast of the axis of the …
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Geology of the Poplar Hill area Giles County, Virginia
… marine sedimentary rocks that range in age from Middle Cambrian to Middle Bilurian. The formations trend northeast in narrow outcrop belts. The summit of Walker Mountain is the southeastern boundary of the area and the southern slopes of Brushy and Buckeye Mountains form the northwestern …
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A revision of helicoplacoids and other early Cambrian echinoderms of North America
The Lower Cambrian rocks of North America contain the remains of several species of echinoderms, including helicoplacoids, the eocrinoids Gogia, Lepidocystis, and Kinzercystis, and the edrioasteroids Camptostroma and Stromatocystites. Camptostroma roddyi Ruedemann, 1933 is a large echinoderm from …
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The structural geology of the Southern Norwegian Caledonides in the Oslo Graben and Sparagmite region
… SSE. After ramping through the Hedmark Group (Eocambrian) the Osen-Ro Thrust forms the bed-parallel detachment in the Alum Shales (Middle Cambrian) of the Oslo Graben. Therefore, it is proposed that the Osen-Roa Thrust Sheet continues into the Oslo Graben.
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Paleontology and stratigraphy of the Nolichucky Formation in southwest Virginia and northeast Tennessee
… and identified. The faunas range from late Middle Cambrian (Bolaspidella Zone) to late Upper Cambrian (Trempealeau), but the majority are of Dresbachian age. Trilobites are the most common faunal element with M8 genera and 85 species represented. Two new genera and eight new species are …
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Geology of part of the Inchelium Quadrangle, Stevens County, Washington
… units are recognized: Addy Quartzite (Early Cambrian), Maitlen Phyllite (Early Cambrian), Metaline Limestone (Middle Cambrian), Ledbetter Slate (Middle Ordovician), and unnamed quartz monzonite, granodiorite, quartz latite, and rhyodacite intrusive rocks of probable Cretaceous age. Evidence …
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Structural geology of the Pulaski-Salem thrust sheet and the eastern end of the Christiansburg window, southwestern Virginia
… County, Virginia. The bedrock ranges in age from Cambrian to Devonian and belongs to five fault blocks. From north to south they are Catawba, Salem, Pulaski, Saltville and Max Meadows. The structurally lowest block is the parautochthonous Saltville block which is exposed in the Christiansburg …
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Geology of the Big Walker Mountain-Crockett Cove Area, Bland, Pulaski, and Wythe counties, Virginia
… of southwestern Virginia and is made up of Middle Cambrian-Lower Mississippian strata which are exposed in two separate northeast-trending strike belts. The area is bounded on the northwest by the northwestern limb of the Greendale syncline which has been overridden from the southeast by …
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Stratigraphy and sedimentology, Cambrian Shady Dolomite, Virginia
Cambrian Shady Dolomite facies exposed northwest and southeast of Austinville, southwestern Virginia, apparently formed in a platform-to-basin setting. Northwest of Austinville, the Shady Dolomite (600 m thick) overlies the Lower Cambrian Erwin Formation and is overlain by the Middle Cambrian Rome …
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Geochemical investigations of the late early Cambrian extinctions
Following the radiation of animals in the early Cambrian, the reef-building archaeocyathids went extinct around 513 – 508 Ma and redlichiid and olenellid trilobites went extinct around 506 Ma. Both extinction events have been documented to occur with negative carbon isotope excursions (CIEs) that …
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Geology of the Millers Cove area, Roanoke, Craig and Montgomery counties, Virginia
… area is underlain by rock ranging in age from Middle Cambrian Elbrook Dolomite to Early Mississippian Price Sandstone. Carbonate deposition was dominant into the Ordovician with elastic sedimentation dominant throuhout the rest of the Paleozoic. Cove Mountain is formed by the overturned …
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The geology of the upper Roanoke River Valley area, Montgomery and Roanoke counties, Virginia
… Paleozoic age and of sedimentary origin. The Precambrian rocks that crop out on Poor Mountain were not subdivided or studied in detail in the field. The aggregate thickness of the Paleozoic rocks in the area is approximately 5,600 feet. However, parts of these formations are either cut off by …
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