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Effects of volcanism on the glaciers of Mount St. Helens Effects of volcanism on the glaciers of Mount St. Helens

The cataclysmic eruption of Mount St. Helens May 18, 1980, removed 2.9 km2 (about 0.13 km3) of glacier snow and ice including a large part of Shoestring, Forsyth, Wishbone, Ape, Nelson, and all of Loowit and Leschi Glaciers. Minor eruptions and bulging of the volcano from March 27 to May 17 shattered glaciers which were on the deforming rock and deposited ash on other glaciers. Thick ash...
Authors
Melinda M. Brugman, Austin Post

Guides to some volcanic terranes in Washington, Idaho, Oregon, and Northern California Guides to some volcanic terranes in Washington, Idaho, Oregon, and Northern California

This guidebook arose out of a series of field trips held in conjunction with the Pacific Northwest American Geophysical Union meeting held in Bend, Oregon, September 1979. The PNAGU meeting included special volcanology sessions planned by William I. Rose, Jr., Bruce A. Nolf, amd David A. Johnston. Publication of the guidebook volume was originally planned for early 1980 by the Oregon...
Authors
David A. Johnston, Julie M. Donnelly-Nolan

Aeromagnetic map of the Mt. St. Helens area, Washington Aeromagnetic map of the Mt. St. Helens area, Washington

No abstract available.
Authors
Water Resources Division U.S. Geological Survey

Potassium-argon ages from the Mount Taylor Volcanic Field, New Mexico Potassium-argon ages from the Mount Taylor Volcanic Field, New Mexico

Fourteen new K-Ar dates for volcanic rocks of the Mount Taylor field, New Mexico, indicate that most activity occurred between 4.3 and 1.5 m.y. (million years) ago. Peak activity was at about 3.0-2.5 m.y., both on the central andesite-rhyolite shield volcano and on the surrounding alkali basalt-trachyte volcanic plateau, and occurred concurrently with an episode of NNE-trending basin...
Authors
Peter W. Lipman, Harald H. Mehnert

Late Cenozoic volcanism, geochronology, and structure of the Coso Range, Inyo County, California Late Cenozoic volcanism, geochronology, and structure of the Coso Range, Inyo County, California

The Coso Range lies at the west edge of the Great Basin, adjacent to the southern part of the Sierra Nevada. A basement complex of pre‐Cenozoic plutonic and metamorphic rocks is partly buried by ∼35 km3 of late Cenozoic volcanic rocks that were erupted during two periods, as defined by K‐Ar dating: (1) 4.0–2.5 m.y., ∼31 km3 of basalt, rhyodacite, dacite, andesite, and rhyolite, in...
Authors
Wendell A. Duffield, Charles R. Bacon, G. Brent Dalrymple

Distribution of Quaternary rhyolite domes of the Coso Range, California: implications for extent of the geothermal anomaly. Distribution of Quaternary rhyolite domes of the Coso Range, California: implications for extent of the geothermal anomaly.

38 separate domes and flows of phenocryst-poor, high-silica rhyolite of similar major element chemical composition were erupted over the past 1My from vents arranged in a crudely S-shaped array atop a granitic horst in the Coso Range, California. Most of the extrusions are probably less than about 0.3My old. The central part of the rhyolite field is characterized by high heat flow, low...
Authors
C. R. Bacon, W. A. Duffield
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