Filters: Tags: graben (X)
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This 1:50,000-scale geologic map represents a compilation of the most recent geologic studies of the upper Arkansas River valley, between Leadville and Salida, Colorado. The valley is structurally controlled by an extensional fault system that forms part of the prominent northern Rio Grande rift, an intra-continental region of crustal extension. This work also incorporates new detailed geologic mapping of poorly understood areas within the map area and reinterprets previously studied areas, aided by lidar data that covers 59 percent of the map area. The mapped region extends into the Proterozoic metamorphic and intrusive rocks in the Sawatch Range west of the valley and the Mosquito Range to the east. Paleozoic...
Categories: Data;
Tags: 207Pb/206Pb zircon age,
40Ar/39Ar age,
Arkansas River,
Balltown,
Balltown placer gold mining areas,
Seismic refraction profiling and gravity measurements along the length of the northern Devils Lane graben in Canyonlands National Park reveal that the bedrock floor of the graben is buried beneath a sedimentary cover more than 90 m thick, at least four to ten times more fill than previously measured. This sediment thickness, when combined with exposed fault topography, yields a throw of ≥145 m on the master fault. We estimate that horizontal extensional strain across the graben is on the order of 2–3%, and if this is typical of grabens elsewhere in Canyonlands the maximum average strain rates across the region are about 1×10−14 s−1, or 2 mm year−1. Our results indicate that published length to displacement relationships...
Categories: Publication;
Types: Citation,
Journal Citation;
Tags: Geophysical exploration,
Graben,
Journal of Structural Geology,
development,
extension,
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