Publications
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The geochemistry of hot spring waters at Norris Geyser Basin, Yellowstone National Park The geochemistry of hot spring waters at Norris Geyser Basin, Yellowstone National Park
No abstract available.
Authors
Robert O. Fournier, J. Michael Thompson, Roderick A. Hutchinson
Chemical, isotopic, and dissolved gas compositions of the hot springs of the Owyhee Uplands, Malheur County, Oregon Chemical, isotopic, and dissolved gas compositions of the hot springs of the Owyhee Uplands, Malheur County, Oregon
Hot springs along the Owyhee River in southeastern Oregon between Three Forks and Lake Owyhee could be part of a north flowing regional system or a series of small separate geothermal systems Heat for the waters could be from a very young (Holocene) volcanic activity (basalt flows) of the Owyhee Uplands or the regional heat flow. The springs discharge warm to hot, dilute, slightly...
Authors
Robert H. Mariner, H.W. Young, William C. Evans
Explosive tephra emissions of Mount St. Helens, 1989-1991: the violent escape of magmatic gas following storms? Explosive tephra emissions of Mount St. Helens, 1989-1991: the violent escape of magmatic gas following storms?
From 24 August 1989 until 18 June 1991, Mount St. Helens produced at least 28 shallow, explosion-like seismic events with signatures similar to those produced by gas explosions on the dome during the mid 1980s. At least six were accompanied by violent emission of non-juvenile tephra, ejection of blocks of rock nearly 1 km from the vent, and avalanching of debris off the north side of the...
Authors
L.G. Mastin
An experiment to detect and locate lightning associated with eruptions of Redoubt Volcano An experiment to detect and locate lightning associated with eruptions of Redoubt Volcano
A commercially-available lightning-detection system was temporarily deployed near Cook Inlet, Alaska in an attempt to remotely monitor volcanogenic lightning associated with eruptions of Redoubt Volcano. The system became operational on February 14, 1990; lightning was detected in 11 and located in 9 of the 13 subsequent eruptions. The lightning was generated by ash clouds rising from...
Authors
R. Hoblitt
Stream-channel changes in response to volcanic detritus under natural and augmented discharge, South Coldwater Creek, Washington Stream-channel changes in response to volcanic detritus under natural and augmented discharge, South Coldwater Creek, Washington
No abstract available.
Authors
D. F. Meyer
Dissolved volatile concentrations in an ore-forming magma Dissolved volatile concentrations in an ore-forming magma
Infrared spectroscopic measurements of glass inclusions within quartz phenocrysts from the Plinian fallout of the 22 Ma tuff of Pine Grove show that the trapped silicate melt contained high concentrations of H2O and CO2. Intrusive porphyries from the Pine Grove system are nearly identical in age, composition, and mineralogy to the tephra, and some contain high-grade Mo mineralization...
Authors
J. B. Lowenstern
Origin of phenocrysts and compositional diversity in pre-Mazama rhyodacite lavas, Crater Lake, Oregon Origin of phenocrysts and compositional diversity in pre-Mazama rhyodacite lavas, Crater Lake, Oregon
Phenocrysts in porphyritic volcanic rocks may originate in a variety of ways in addition to nucleation and growth in the matrix in which they are found. Porphyritic rhyodacite lavas that underlie the eastern half of Mount Mazama, the High Cascade andesite/dacite volcano that contains Crater Lake caldera, contain evidence that bears on the general problem of phenocryst origin. Phenocrysts...
Authors
S. Nakada, C. R. Bacon, A.E. Gartner
Multiple isotopic components in Quaternary volcanic rocks of the Cascade Arc near Crater lake, Oregon Multiple isotopic components in Quaternary volcanic rocks of the Cascade Arc near Crater lake, Oregon
Quaternary lavas and pyroclastic rocks of Mount Mazama, Crater lake caldera, and the surrounding area have variable Sr, Nd, and Pb isotopic compositions. High-alumina olivine tholeiites have 87Ar/86Ar ratios of 0.70346-0.70364; basaltic andesite, 0.70349-0.70372; shoshonitic basaltic andesite, 0.70374-0.70388; and andesite, 0.70324-0.70383. Dacites of Mount Mazama have 87Sr/ 86Sr ratios...
Authors
C. R. Bacon, S.H. Gunn, M. A. Lanphere, J. L. Wooden
Russian volcanic eruption disrupts north pacific air traffic: Alaska Volcano Observatory fact sheet Russian volcanic eruption disrupts north pacific air traffic: Alaska Volcano Observatory fact sheet
No abstract available.
Authors
Thomas P. Miller, Vladimir Yu. Kirianov, H. Lee Kelley
Giant Hawaiian landslides Giant Hawaiian landslides
Sixty-eight landslides more than 20 km long are present along a 2200 km segment of the Hawaiian Ridge from near Midway to Hawaii. Some of the landslides exceed 200 km in length and 5000 km3 in volume, ranking them among the largest on Earth. Most of these giant landslides were discovered during a mapping program of the U.S. Hawaiian Exclusive Economic zone from 1986 to 1991 utilizing the...
Authors
J.G. Moore, W. R. Normark, R. T. Holcomb