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Showing 1 to 8 of 8 for “"Stratigraphic--Ordovician"”.
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Depositional and paragenetic controls on porosity development, upper Red River Formation, North Dakota
… units each, labeled "P," "R," and "F" in stratigraphic order. Four porosity zones are recognized in the upper Red River: the subtidal/ intertidal facies forms one porosity zone, and each evaporitic sequence contains another. Each unit in a sequence, as well as the sequence itself, is …
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Depositional environments and history of the Winnipeg Group (Ordovician), Williston Basin, North Dakota
<p>The Winnipeg Group (Ordovician) in the Williston Basin, North Dakota, contains three formations. They are, in ascending order, the Black Island Formation, herein informally divided into lower and upper members, the Icebox Formation, and the Roughlock Formation. Strata of the Winnipeg Group …
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Stratigraphy of the Winnipeg and Deadwood Formations in North Dakota
<p>The Deadwood formation includes all of the pre-Winnipeg sedimentary rocks of North Dakota which range in thickness from an erosional edge in the subsurface of northeastern North Dakota to at least 1,000 feet in northwestern North Dakota. It is composed of sandstone, shale, and carbonate of Late …
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Discontinuities in the Icebox Formation (Ordovician), Williston Basin, North Dakota and Montana
<p>The Ordovician Winnipeg Group is composed of three formations; in ascending order, the Black Island Formation, the Icebox Formation, and the Roughlock Formation. The Icebox Formation is largely composed of shale. This work shows that discontinuities and coarser facies exist within the Icebox …
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Stratigraphy and Depositional History of the Deadwood Formation (Upper Cambrian and Lower Ordovician), Williston Basin, North Dakota
… Cambrian in age; members C through Fare Early Ordovician in age. The type section of the Deadwood, in the northern Black Hills, is dominated by Upper Cambrian strata. Much thicker Lower Ordovician rocks occur in the deeper portion of the Williston Basin.</p> <p>The Deadwood comprises the Sauk …
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Depositional environments and paleogeography of the Winnipeg Group (Ordovician), Williston Basin, North Dakota
<p> The Winnipeg Group (Upper Ordovician) unconformably overlies the Deadwood Formation (Cambrian - Lower Ordovician) over most of North Dakota, except in the extreme eastern part, where it lies directly on Precambrian basement rocks. The Winnipeg is conformably overlain by the Red River Formation …
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Depositional and diagenetic controls on porosity evolution in the "C" zone, Red River Formation (Upper Ordovician), Divide County, North Dakota
… the "C" zone c: the Red River Formation (Upper Ordovician) in the subsurface of Divide County, North Dakota, were studied in order to determine the geologic framework of porosity evolution in this important hydrocarbon-producing formation. Examination of 28 cores, petrographic analysis, …
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Depositional and Diagenetic History of the Middle Ordovician Carbonates of the Shenandoah Valley, Northern Virginia
<p>An examination of the Middle Ordovician carbonates in northwest Virginia has revealed a particularly sensitive record of deposition and subsidence. Two-hundred acetate peels from six measured stratigraphic sections in Shenandoah County, Virginia were examined to interpret the depositional and …