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Summary -- The Chelan quadrangle hosts a wide variety of rocks and deposits and display a long geologic history ranging from possible Precambrian to Recent. Two major structures, the Leavenworth and Entiat faults divide cross the quadrangle from southeast to northwest and bound the Chiwaukum 'graben', a structural low preserving...

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This volume of the U.S. Geological Survey Yearbook is special, the first we have ever dedicated to an individual.  While we were preparing that repost, Vincent E. McKelvey, eminent scientist and former Director of the Geological Survey died.  Because of his deep devotion not only to his science but also...

Conservation Act of 1980 (ANILCA, 1980) requires the Secretary of Interior to conduct a continuing study of fish, wildlife, and habitats on the Innoko National Wildlife Refuge (INWR). Included in this study is a determination of the extent, location, and carrying capacity of fish and wildlife habitats....

Bacterial activities and abundance were measured seasonally in the water column of meromictic Big Soda Lake which is divided into three chemically distinct zones: aerobic mixolimnion, anaerobic mixolimnion, and anaerobic monimolimnion. Bacterial abundance ranged between 5 and 52 x 106 cells ml−1, with highest biomass at the interfaces between these zones:...

The Recent (<15000 y) volcanic complex of southwest Naivasha, Kenya, consists of mildly peralkaline (comenditic) rhyolite domes, lava flows, air fall pumices, and lake sediments, with minor, peripheral, basalts and hawaiites. The comendites are either aphyric or sparsely porphyritic, few samples containing >5 per cent phenocrysts. Phenocryst minerals are quartz-sanidine-ferrohedenbergite-fayalite-titanomagnetite-ilmenite-riebeckite-arfvedsonite-aenigmatite-biotite-zircon....

Some areas of the E.E.Z. (Exclusive Economic Zone) offer technical, political and economic options that may complement existing approaches to hazardous waste storage and disposal....

Two basic concepts pertaining to the history of the Heart Mountain fault of northwestern Wyoming have recently been challenged; one, that there was tectonic denudation, and two, that volcanic rock of the Wapiti Formation was deposited on the exposed fault surface. Tectonic denudation is believed to have occurred as a...

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Gridded surface data sets are often incorporated into digital data bases, but extracting information from the data sets requires specialized raster processing techniques different from those historically used on remotely sensed and thematic data. Frequently, the information desired of a gridded surface is directly related to the topologic peaks and...

Evidence of late Paleozoic (Alleghanian) penetrative deformation, amphilbolite-facies, metamorphism, and syntectonic granite emplacement has been found in an area of the central Piedmont in the southern Appalachians. The High Shoals Granite batholith in the Kings Mountain belt of south-central North Carolina consists of coarse-grained, megacrystic biotite granite with a strong,...

A new marine diatom genus and species, Adoneis pacifica G.W. Andrews and P. Rivera, has been identified in Chilean coastal waters. This taxon shows obvious affinities to the genera Rhaphoneis and Delphineis, but cannot be classified in either, as they are currently construed. Adoneis pacifica resembles Rhaphoneis in outline and to some degree in the...

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Vector-based geographic information systems usually require annotation, such as a polygon number or attribute data, in a suitable location within a polygon. Traditional methods usually compute the polygon centroid, test the centroid for inclusion or exclusion, and select some alternative point when the centroid falls outside the polygon. Two problems...

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Late Quaternary calderas have been identified at 12 of 40 volcanic centers in the eastern Aleutian arc, and sufficient radiocarbon dates and geologic information have now been obtained to either date or constrain the timing of the climactic caldera-forming eruptions. At least eight major caldera-forming events, each characterized by estimated...

Indicators of organic metamorphism provide valuable tools for analyzing the thermal history of tectonostratigraphic terranes. Paleotemperature estimates derived from vitrinite reflectance, for example, are more precise than values based upon inorganic mineral assemblages in low‐grade rocks. Isothermal geometries must be interpreted within the context of structural...

The protolith and metamorphic histories of Early Cretaceous blueschists that occur in Washington, Oregon, and California are remarkably similar. These blueschists are the Shuksan metamorphic suite of northwestern Washington, the Condrey Mountain schist of northern California and southern Oregon, and the Pickett Peak terrane of northern California and southwestern Oregon....