Publications
Filter Total Items: 3018
Groundwater flow-field in infinite slopes Groundwater flow-field in infinite slopes
No abstract available.
Authors
R.M. Iverson
Monitoring the hydrologic system for potential effects of geothermal and ground-water development in the Long Valley caldera, Mono County, California, U.S.A. Monitoring the hydrologic system for potential effects of geothermal and ground-water development in the Long Valley caldera, Mono County, California, U.S.A.
In the early 1980's, renewed interest in the geothermal potential of the Long Valley caldera, California, highlighted the need to balance the benefits of energy development with the established recreational activities of the area. The Long Valley Hydrologic Advisory Committee, formed in 1987, instituted a monitoring program to collect data during the early stages of resource utilization...
Authors
C. D. Farrar, D. L. Lyster
Rhyolitic calderas of the Yukon-Tanana Terrane, east central Alaska: volcanic remnants of a mid-Cretaceous magmatic arc Rhyolitic calderas of the Yukon-Tanana Terrane, east central Alaska: volcanic remnants of a mid-Cretaceous magmatic arc
Four large but poorly exposed rhyolitic calderas are present in the Yukon-Tanana terrane (YTT) in east central Alaska. At least two are mid-Cretaceous in age (~93 Ma). Similar volcanic rocks, the South Fork Volcanics, occur northeast of the Tintina fault in Yukon Territory. Evidence for the calderas consists of thick deposits of devitrified crystal- and lithic-rich densely welded tuff...
Authors
C. R. Bacon, H.L. Foster, James G. Smith
Mount Mazama and Crater Lake caldera, Oregon Mount Mazama and Crater Lake caldera, Oregon
No abstract available.
Authors
Charles R. Bacon
IGC field trip T312: South cascades arc volcanism, California and southern Oregon IGC field trip T312: South cascades arc volcanism, California and southern Oregon
No abstract available.
Authors
L.J. Patrick Muffler, Charles R. Bacon, Robert L. Christiansen, Michael A. Clynne, Julie M. Donnelly-Nolan, Cheryl Miller, David R. Sherrod, J.C. Smith
Measures of little gravity Measures of little gravity
No abstract available.
Authors
Robert I. Tilling
Direct evidence for the origin of low-18O silicic magmas: quenched samples of a magma chamber's partially-fused granitoid walls, Crater Lake, Oregon 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...
Authors
Charles R. Bacon, Lanford H. Adami, Marvin A. Lanphere
Dynamic pore-pressure fluctuations in rapidly shearing granular materials 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...
Authors
Richard M. Iverson, Richard G. Lahusen
Petrology of the zoned calcalkaline magma chamber of Mount Mazama, Crater Lake, Oregon 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...
Authors
T. H. Druitt, C. R. Bacon
Preliminary geologic map of the Puu Anahulu quadrangle, Hawaii 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...
Authors
Richard B. Moore, David A. Clague, Wendy A. Bohrson, W. S. Wise
Guidebook for field trip to the Mount Bachelor-South Sister-Bend area, central Oregon High Cascades 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