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Showing 1 to 12 of 12 for “"The North American Craton"”.
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Mantle flow and lithosphere-asthenosphere coupling beneath the southwestern edge of the North American craton: constraints from shear-wave splitting measurements
… broadband seismic data recorded by the USArray and other stations in the southwestern United States provide a unique opportunity to test different models of anisotropy-forming mechanisms in the vicinity of a cratonic edge. Systematic spatial variations of anisotropic characteristics …
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Ordovician paleoceanography: Stable isotope and carbon-sulfur-iron evidence from the Caradocian Trenton Group, Mohawk Valley, New York
… from Caradocian Trenton Group brachiopods in the Mohawk Valley of New York suggests that Caradocian oceans were salinity-stratified and dominated at depth by warm, saline waters. $\delta\sp{18}$O values of these brachiopods, which lived on the eastern continental slope of the North American …
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Continental Tectonics from Dense Array Seismic Imaging: Intraplate Seismicity in Virginia and a Steep Cratonic Margin in Idaho
… high-resolution hypocenter locations. The two regions presented here include an intraplate seismogenic fault zone in Virginia and a steep cratonic margin in eastern Oregon and Idaho. The intraplate seismicity study in Virginia consisted of using 201 short-period vertical-component …
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Timing and emplacement of the Philipsburg batholith, SW Montana, and a comparison of two magnetic fabric techniques
Magnetic anisotropy is widely used for measuring the orientation of minerals in many rock types. The anisotropy of magnetic susceptibility (AMS) is used extensively to determine magma flow fabrics in both intrusive and extrusive igneous rocks. The anisotropy of anhysteretic remanent magnetization …
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Structural Geology of The Brady Mountain Area, Ouachita Mountains, Arkansas: Integrating Field Mapping, Geospatial Techniques, Photogrammetry And 3D Modeling For Structural Analysis
<p>Much of the Ouachita orogenic belt, representing the deformed Paleozoic rocks flanking the southern margin of the North American craton, is buried beneath post-orogenic Mesozoic and Tertiary sediments composing the Gulf Coastal Plain. The Ouachita Mountains of Arkansas and Oklahoma are the …
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Joint modeling receiver functions and autocorrelograms to estimate crustal structure in the presence of deep sediments.
… distant earthquakes to image local structure. They record the interactions of teleseismic P waves with impedance contrasts, such as the Moho and sediment-basement interface, which generate conversions of P type to S type energy. Typically, receiver functions are used to determine contrast depth …
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Stratigraphy and Depositional History of the Deadwood Formation (Upper Cambrian and Lower Ordovician), Williston Basin, North Dakota
<p>Based on gamma-ray characteristics, the Deadwood Formation is divided into six informal, attribute-defined units, members A through F. Members A and Bare Late Cambrian in age; members C through Fare Early Ordovician in age. The type section of the Deadwood, in the northern Black Hills, is …
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Lithological and sequence stratigraphic examination of the Madison Group marker beds, eastern Williston Basin margin, North Dakota
<p>The Frobisher-Alida interval consists of eight log-defined subintervals or “beds” within the Mississippian upper Mission Canyon and lower Charles Formations of the Madison Group in the Williston Basin. The subintervals are composed of predominantly evaporite and carbonate lithologies, and …
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The Midcontinent exposed: Precambrian basement topography, and fault-and-fold zones, within the cratonic platform of the United States
"The Midcontinent region of the United States is part of the cratonic platform of the North American craton. This region is underlain by Precambrian basement formed dominantly during Proterozoic accretionary orogenies. It was modified by Proterozoic anorogenic felsic magmatism and was cracked by …
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Morphological diversification of the ptychopariid trilobites in the Marjumiid biomere (Middle to Upper Cambrian)
… shows that extinction events sharply reduced the morphological diversity of ptychopariid trilobites living on the shelf at the lower boundaries of the Marjumiid, Pterocephaltid, and Ptychaspid biomeres (Middle to Upper Cambrian). These extinction events not only separate the trilobite …
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Stratigraphy, Sedimentology, and Ichnology of the Middle Cambrian to Lower Ordovician Deposits in Subsurface Western Canada
During the past 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 …
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Seismic studies in the midcontinent of U.S. and its implications for the intraplate deformation process
… a 24 month embargo labeled 'U of I Access', the embargo will last until 2025-12-01