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Monitoring the hydrothermal system in Long Valley caldera, California Monitoring the hydrothermal system in Long Valley caldera, California

An ongoing program to monitor the hydrothermal system in Long Valley for changes caused by volcanic or tectonic processes has produced considerable data on the water chemistry and discharge of springs and fluid temperatures and pressures in wells. Chemical and isotopic data collected under this program have greatly expanded the knowledge of chemical variability both in space and time...
Authors
C. D. Farrar, M.L. Sorey

Origin of Hawaiian tholeiite: A metasomatic model Origin of Hawaiian tholeiite: A metasomatic model

Two voluminous magma types generated in the mantle underlying the Pacific plate are mid‐ocean ridge tholeiite (MORB) erupted at the East Pacific Rise spreading center and Hawaiian tholeiite (HT) erupted above the Hawaiian hot spot or melting anomaly. MORB has low initial 87Sr/86Sr ratios and low amounts of all incompatible trace elements including rare earths; chondrite‐normalized...
Authors
Thomas L. Wright

Deformation in the White Mountain seismic gap, California-Nevada, 1972-1982 Deformation in the White Mountain seismic gap, California-Nevada, 1972-1982

A 100×40 km trilateration network extending from Bishop, California, to near Hawthorne, Nevada, crosses the east end of the Long Valley caldera, site of renewed magma inflation in the 1979–1980 interval, and spans most of the White Mountain seismic gap. The network was surveyed in 1972, 1973, 1976, 1979, 1980, and 1982. The 1980 survey may be contaminated by a scale error. In addition...
Authors
James C. Savage, Michael Lisowski

Volcanic hazards in Indonesia: The 1982-83 eruption of Galunggung Volcanic hazards in Indonesia: The 1982-83 eruption of Galunggung

Indonesia faces a perpetual volcanic-hazards problem of enormous proportions, exemplified by the 1982-83 eruption of Galunggung in West Java. Though moderate in size, this caused widespread destruction and a marked socio-economic impact on more than half a million people. The prolonged activity provided and opportunity for the Volcanological Survey of Indonesia to conduct systematic...
Authors
A. Sudradjat, Robert I. Tilling

Forecasting eruptions in the Circum-Pacific Forecasting eruptions in the Circum-Pacific

Many important advances have been made in the last few years in the techniques and approaches to forecasting volcanic eruptions. Yet some of the most dangerous volcanoes are in countries unable to provide either the equipment or the skills to monitor them and to warn endangered residents. This review of the many scientific, technical, social and even political factory involved in volcano
Authors
J.G. Souther, Robert I. Tilling, R.S. Punongbayan

Correlation of the middle eocene Kellogg Shale of northern California Correlation of the middle eocene Kellogg Shale of northern California

The Kellogg Shale of northern California has traditionally been considered to be late Eocene in age on the basis of benthic foraminifer, radiolarian, and diatom correlations. The 30-m-thick Kellogg section exposed west of Byron, California, however, contains middle Eocene planktonic foraminifers (Zone P12), coccoliths (Subzones CP13c and CP14a), silicoflagellates (Dictyocha hexacantha...
Authors
John A. Barron, David Bukry, Richard Z. Poore

Neogene silicoflagellates from Deep Sea Drilling Project Site 543, western tropical Atlantic Ocean Neogene silicoflagellates from Deep Sea Drilling Project Site 543, western tropical Atlantic Ocean

The upper lower Miocene silicoflagellate assemblage in Core 19 from DSDP Hole 543 in the western Atlantic Ocean contains the greatest concentration (41%) of deflandroid Dictyochapulchella yet observed. The deflandroid morphology in Dictyocha persisted through the Eocene and Oligocene at middle and high latitude, but virtually disappeared in the late Oligocene, only to reappear as a short...
Authors
David Bukry

Cenozoic silicoflagellates from Rockall Plateau, Deep Sea Drilling Project Leg 81 Cenozoic silicoflagellates from Rockall Plateau, Deep Sea Drilling Project Leg 81

Eocene to Pliocene silicoflagellates from the Rockall Plateau are sparse to moderately abundant and include assem blages at the upper and lower boundaries of the Miocene Series. Relative paleotemperature values for silicoflagellates from the upper Miocene and lower Pliocene at DSDP Hole 552A based on quantitative data are cooler than are those from equatorial Pacific Sites 503 and 504...
Authors
David Bukry

Paleogene paleoceanography of the Arctic Ocean is constrained by the middle or late Eocene age of USGS Core Fl-422: Evidence from silicoflagellates Paleogene paleoceanography of the Arctic Ocean is constrained by the middle or late Eocene age of USGS Core Fl-422: Evidence from silicoflagellates

Arctic Ocean Core Fl-422 has been of central importance in Arctic tectonics and paleoceanography because it provides the sole evidence for early Cenozoic marine conditions in the Arctic. The presence of several Eocene and Eocene or Oligocene guide species of silicoflagellates in samples from this core shows that it is no older than middle Eocene, and is not Paleocene as previously...
Authors
David Bukry

Ultrathin lava layers exposed near San Luis Obispo Bay, California Ultrathin lava layers exposed near San Luis Obispo Bay, California

Sequences of extraordinarily thin (1–5 cm thick) lava layers, resembling individual lava flows, are interbedded with Jurassic and Cretaceous pillowed lava flows near San Luis Obispo Bay on the California coast. Such layers are formed inside submarine pillowed lava pipes or flow lobes. As the lava surface in a pillow pipe falls to a lower level owing to diminished supply entering the pipe...
Authors
James G. Moore, D.W. Charlton

Magmatic inclusions in rhyolites, contaminated basalts, and compositional zonation beneath the Coso volcanic field, California Magmatic inclusions in rhyolites, contaminated basalts, and compositional zonation beneath the Coso volcanic field, California

Basaltic lava flows and high-silica rhyolite domes form the Pleistocene part of the Coso volcanic field in southeastern California. The distribution of vents maps the areal zonation inferred for the upper parts of the Coso magmatic system. Subalkalic basalts (
Authors
C. R. Bacon, J. Metz
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