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Environmental Geochemical Studies of Selected Mineral Deposits in Wrangell-St. Elias National Park and Preserve, Alaska

Description: From abstract: Environmental geochemical investigations took place in Wrangell-St. Elias National Park and Preserve (WRST), Alaska, between 1994 and 1997. Areas studied include the historic Kennecott stratabound copper mines and mill area; the historic mines and mill in the Bremner district, where gold was produced from polymetallic veins; the sporadically active gold placer mines at Gold Hill; the undisturbed, unmined porphyry copper-molybdenum deposits at Orange Hill and Bond Creek; and the historic mines and mill at Nabesna, where gold-bearing iron skarn deposits were exploited. The cooperative study between the U.S. Geological Survey and the National Park Service focused on identifying and characterizing geochemical signatures associated with these mineralized areas. Sample media included surface water, bedload sediment, rock, mine waste, and mill tailings samples.
Date: 2000
Creator: Eppinger, Robert G.; Briggs, Paul H.; Rosenkrans, Danny S. & Ballestrazze, Vanessa
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[Evolution of Sedimentary Basins/Onshore Oil and Gas Investigations--Santa Maria Province: Chapters Y and Z]

Description: From abstract: A complex Neogene history characterizes the offshore Santa Maria basin and the northwest margin of the western Transverse Ranges, California. This history includes the transition from subduction to a transtensional and then transpressional plate boundary, including about 900 of clockwise rotation of the western Transverse Ranges. This report uses seismic reflection data to document the geometry of structures that accommodated this deformation and offshore well data to date and correlate the sediments which were affected by the different tectonic episodes.
Date: 1999
Creator: Sorlien, Christopher C.; Nicholson, Craig; Luyendyk, Bruce P.; Miller, Kate C. & Meltzer, Anne S.
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[Evolution of Sedimentary Basins/Onshore Oil and Gas Investigations--Santa Maria Province: Chapters W and X]

Description: From abstract: Bulletin W is about the deformation of the Mesozoic Franciscan Complex of the Eastern Santa Maria basin in California. Bulletin X is about the regional thermal maturity of the surface rocks of the mentioned basin as well as the Santa Barbara-Ventura basin area in California.
Date: 1998
Creator: Wahl, Arthur D.; Naeser, Nancy D.; Isaacs, Caroline M. & Keller, Margaret A.
open access

Lateral Ramps in the Folded Appalachians and in Overthrust Belts Worldwide—A Fundamental Element of Thrust-Belt Architecture

Description: A report about lateral ramps which are zones where décollements change stratigraphic level along a strike. This report suggests that many cross-strike features may be underlain by lateral ramps that serve to transfer décollements from one stratigraphic level to another in the same manner as frontal ramp, but in a direction normal to the strike of the fold belt.
Date: 1998
Creator: Pohn, Howard A.
open access

Geology of the Pennsylvanian and Permian Cutler Group and Permian Kaibab Limestone in the Paradox Basin, Southeastern Utah and Southwestern Colorado

Description: From abstract: This report talks about the geology of the Pennsylvanian and Permian Cutler Group that consists of the lower Cutler beds, Cedar Mesa Sandstone, Organ Rock Formation, White Rim Sandstone, and De Chelly Sandstone. The report also talks about the Permian Kaibab Limestone in the Paradox Basin that overlays the Cutler.
Date: 1997
Creator: Condon, Steven M.
open access

Paleomagnetic and 40Ar/39Ar Results from the Grant Intrusive Breccia and Comparison to the Permian Downeys Bluff Sill—Evidence for Permian Igneous Activity at Hicks Dome, Southern Illinois Basin

Description: A report about applying 40Ar/39Ar dating methods, along with other rock techniques, to determine the age of emplacement and the cooling history of the Grant intrusive breccia at Hicks dome in Illinois.
Date: 1997
Creator: Reynolds, Richard L.; Goldhaber, Martin B. & Snee, Lawrence W.
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Proterozoic Geology of the Granite Village Area, Albany and Laramie Counties, Wyoming, Compared with that of the Sierra Madre and Medicine Bow Mountains of Southeastern Wyoming

Description: Abstract: "Precambrian metavolcanic rocks north and south of the village of Granite, Wyoming, belong to a sequence of isolated metavolcanic and metasedimentary masses in the Sherman Granite of the southern Laramie Mountains. Similar rocks lie to the west, in the Precambrian uplifts of the southern Medicine Bow Mountains and Sierra Madre. A major fault system, the Cheyenne belt, splits these two ranges into northern and southern domains, and may constitute a suture along which Early Proterozoic islands arcs collided with an Early Proterozoic passive margin. Projection of the Cheyenne belt into the Laramie Mountains suggests that the study area, which is 65 kilometers south of the proposed suture, comprises a distinct volcanic arc with a unique chemistry or age. However, chemistry of the volcanic rocks of the study area as determined as so far does not differ significantly from those of the Medicine Bow Mountains and Sierra Madre."
Date: 1997
Creator: Houston, Robert S. & Marlatt, Gordon
open access

Chronology of Late Cretaceous Igneous and Hydrothermal Events at the Golden Sunlight Gold-Silver Breccia Pipe, Southwestern Montana

Description: A report about gold mineralization at the Golden Sunlight breccia pipe, southwestern Montana, is related to emplacement of Late Cretaceous alkali-calcic rhyolite and subsequent collapse of the Belt Supergroup wallrock and rhyolite in the pipe.
Date: 1996
Creator: DeWitt, Ed; Foord, Eugene E.; Zartman, Robert E.; Pearson, Robert C. & Foster, Fess
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