Publications
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Chemical analyses of volcanic rocks from monogenetic and shield volcanoes near Crater Lake, Oregon
No abstract available.
Authors
P. E. Bruggman, C. R. Bacon, J. S. Mee, S. T. Pribble, D. F. Siems
Preliminary map of upper Eocene to Holocene volcanic and related rocks of the Cascade Range, Oregon
Since 1979 the Geothermal Research Program of the U.S. Geological Survey has carried out multidisciplinary research in the Cascade Range. The goal of this research is to understand the geology, tectonics, and hydrology of the Cascades in order to characterize and quantify geothermal resource potential. A major goal of the program is compilation of a comprehensive geologic map of the entire Cascade
Authors
David R. Sherrod, James G. Smith
Guidebook for field trip to the Mount Bachelor-South Sister-Bend area, central Oregon High Cascades
No abstract available.
Authors
William E. Scott, Cynthia A. Gardner, Scott A. Lundstrom, Brittain E. Hill, Edward M. Taylor, Andrei M. Sarna-Wojcicki, Charles E. Meyer, John K. Nakata, J.L. Slate, P.C. Russell
Direct evidence for the origin of low-18O silicic magmas: quenched samples of a magma chamber's partially-fused granitoid walls, Crater Lake, Oregon
Partially fused granitoid blocks were ejected in the climactic eruption of Mount Mazama, which was accompanied by collapse of Crater Lake caldera. Quartz, plagioclase, and glass in the granitoids have much lower δ18O values (−3.4 to +4.9‰) than any fresh lavas of Mount Mazama and the surrounding region (+5.8 to +7.0‰). Oxygen isotope fractionation between phases in granitoids is consistent with eq
Authors
Charles R. Bacon, Lanford H. Adami, Marvin A. Lanphere
Flow modeling in the Toutle River, Washington
No abstract available.
Authors
Yasuyuki Shimizu, Randy L. Dinehart, J. Dungan Smith
South Arch volcanic field—Newly identified young lava flows on the sea floor south of the Hawaiian Ridge
Several young lava fields were imaged by GLORIA sidescan sonar along the Hawaiian Arch south of Hawaii. The largest, 35 by 50 km across, includes a central area characterized by high sonar backscatter and composed of several flow lobes radiating from a vent area. Reflection profiling and sea-floor photography indicate that the central lobes are flat sheet flows bounded by pillowed margins; thin su
Authors
Peter W. Lipman, David A. Clague, James G. Moore, Robin T. Holcomb
Crystallization of accessory phases in magmas by local saturation adjacent to phenocrysts
Accessory minerals commonly occur attached to or included in the major crystalline phases of felsic and some intermediate igneous rocks. Apatite is particularly common as inclusions, but Fe-Ti oxides, pyrrhotite, zircon, monazite, chevkinite and xenotime are also known from silicic rocks. Accessories may nucleate near the host crystal/ liquid interface as a result of local saturation owing to form
Authors
C. R. Bacon
Petrology of the zoned calcalkaline magma chamber of Mount Mazama, Crater Lake, Oregon
Evolution of the magma chamber at Mount Mazama involved repeated recharge by two types of andesite (high-Sr and low-Sr), crystal fractionation, crystal accumulation, assimilation, and magma mixing (Bacon and Druitt 1988). This paper addresses the modal compositions, textures, mineral chemistry and magmatic temperatures of (i) products of the 6845±50 BP climactic eruption, (ii) blocks of partially
Authors
T. H. Druitt, C. R. Bacon
Earthquakes: Putting good ideas to work
No abstract available.
A mechanical model for lava domes that includes a mechanism for eruptive growth
No abstract available.
Authors
Richard M. Iverson, Roger P. Denlinger
Dynamic pore-pressure fluctuations in rapidly shearing granular materials
Results from two types of experiments show that intergranular pore pressures fluctuated dynamically during rapid, steady shear deformation of water-saturated granular materials. During some fluctuations, the pore water locally supported all normal and shear stresses, while grain-contact stresses transiently fell to zero. Fluctuations also propagated outward from the shear zone; this process modifi
Authors
Richard M. Iverson, Richard G. Lahusen
Preliminary geologic map of the Puu Anahulu quadrangle, Hawaii
Vent deposits and lava flows from Hualalai Volcano and lava flows from Mauna Loa and Mauna Kea Volcanoes cover the Puu Anahulu 7 1/2-minute quadrangle. Hualalai's diffuse north-trending rift zone, marked by the large trachyte cone of Puu Waawaa and several basaltic spatter cones, is located mainly in the southwestern part of the quadrangle. Several Hualalai flows originated in the Hualalai quadran
Authors
Richard B. Moore, David A. Clague, Wendy A. Bohrson, W. S. Wise