Publications

The western metamorphic belt is part of the Coast plutonic-metamorphic complex of western Canada and southeastern Alaska that developed during collision of the Alexander terrane and Gravina assemblage on the west against the Yukon Prong and Stikine terranes to the east. Deformation, metamorphism, and plutonism range from about 120 to 50 Ma. Subgreenschist to lower greenschist facies...

The Ruby terrane is an elongate fragment of continental crustal rocks that is structurally overlain by thrust slices of oceanic crust. Our results from the Kokrines Hills, in the south‐central part of the Ruby terrane, demonstrate that the low‐angle schistose fabric formed under high‐P/low‐T conditions, at peak conditions of 10.8‐13.2 kbar and 425‐550° C, consistent with the rare...

The Plush Ranch Formation (upper Oligocene and lower Miocene) consists of more than 1800 m of nonmarine sedimentary and volcanic rocks that record the history of an extensional basin referred to here as the Plush Ranch basin. Distinctive depositional facies, provenance, and sediment transport directions along each basin margin suggest an asymmetric basin shape that is consistent with a...

The Nenana coal basin extends 240 km in length and 1.5-50 krn in width along the northern foothills of the Alaska Range in central Alaska. Located at the western end of the Nenana basin is the Usibelli Coal Mine, approximately 120 km southwest of Fairbanks. The Tertiary Usibelli Group consists of coal-bearing fluvial and lacustrine sedimentary deposits that were derived from the Yukon...

No abstract available.

Over 62 percent of the 193,000 metric tons of gold discovered to date is located in four countries and more than 68 percent occurs in four types of mineral deposits. About 55 percent of the 1,740,000 metric tons of silver found is in four countries and 45 percent is in four types of deposits. Fifty-six percent of the 1.52 billion metric tons of discovered copper is from four countries...

Ductilely deformed amphibolite facies tectonites comprise two adjacent terranes in east-central Alaska: the northern, structurally higher Taylor Mountain terrane and the southern, structurally lower Lake George subterrane of the Yukon-Tanana terrane. The pressure, temperature, kinematic and age data are interpreted to indicate that the metamorphism of the Taylor Mountain terrane and Lake...

As a part of the U.S. Geological Survey Global Change and Climate History Program we have been studying the biogeochemistry of coastal marshes in Terrebonne Basin, Louisiana. Louisiana has about 40 percent of the coastal wetlands in the conterminous U.S. and it is losing wetlands at one of the highest rates in the U.S. with the conversion of about 65 km2/yr of marsh to open water...

This Open-File report is a digital geologic map database. A pamphlet serves to introduce and describe the digital data. There is no paper map included in the Open-File report. This digital map database is compiled from previously published sources combined with some new mapping and modifications in nomenclature. The geologic map database delineates map units that are identified by...

The biogeochemistry of selected wetlands in the San Luis Valley, Colorado, was examined to assess the effect of acidic, metal-enriched water draining mineralized areas near and around the Summitville Mine. The sampling protocols, analytical methods, and chemical composition of water and stream bed sediment from the Wightman Fork and Alamosa River as well as water, surface sediment or...

No abstract available.

No abstract available.