Publications
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Reappraisal of three calcareous nannofossil species: Coccolithus crassus, Toweius magnicrassus, and Toweius callosus
Type material of calcareous nannofossil index species Coccolithus crassus and two geographically widespread species Toweius magnicrassus and T. callosus have been studied by both light and SEM microscopy and morphometric measurements were made. Coccolithus crassus resembles Coccolithus pelagicus but has a raised cycle of elements around the centre of the distal shield. It probably evolved from C.
Authors
Wuchang Wei, L. Liu, David Bukry
Internal structure of the Sierra Nevada batholith based on specific gravity and gravity measurements
About 6,000 specific‐gravity (SG) measurements of samples collected from nearly 200 granitic plutons comprising the central Sierra Nevada batholith yield a SG contour map across the batholith from 36.25° to 38° north latitude. With notable exceptions, SG decreases from values generally greater than 2.7 in the west to less than 2.6 over a few small areas of high‐silica, high‐potassium granites near
Authors
H.W. Oliver, Bryan Moore, R. F. Sikora
The danger of collapsing lava domes; lessons for Mount Hood, Oregon
Nestled in the crater of Oregon's majestic Mount Hood volcano is Crater Rock, a prominent feature known to thousands of skiers, climbers, and tourists who journey each year to the famous Timberline Lodge located high on the volcano's south flank. Crater Rock stands about 100m above the sloping crater floor and warm fumaroles along its base emit sulfur gases and a faint steam plume that is sometime
Authors
S.R. Brantley, W. E. Scott
Deformation of the Wineglass Welded Tuff and the timing of caldera collapse at Crater Lake, Oregon
Four types of deformation occur in the Wineglass Welded Tuff on the northeast caldera rim of Crater Lake: (a) vertical tension fractures; (b) ooze-outs of fiamme: (c) squeeze-outs of fiamme; and (d) horizontal pull-apart structures. The three types of plastic deformation (b-d) developed in the lower part of the Wineglass Welded Tuff where degree of welding and density are maximum. Deformation orig
Authors
H. Kamata, K. Suzuki-Kamata, C. R. Bacon
Heat flow from four new research drill holes in the Western Cascades, Oregon, U.S.A.
Conceptual models of the thermal structure of the Oregon Cascade Range propose either (1) a narrow zone of magmatic heat sources, flanked by shallow heat-flow anomalies caused by lateral ground-water flow; or (2) a wide zone of magmatic heat sources, with localized, generally negligible ground-water effects. The proposed narrow heat source coincides with the Quaternary volcanic arc, whereas the wi
Authors
S. E. Ingebritsen, M. A. Scholl, D. R. Sherrod
Scanning electron microscope observations of sublimates from Merapi Volcano, Indonesia
Sublimates were sampled from high-temperature (up to 800°C) fumaroles at Merapi volcano, Indonesia in January 1984. Sampling is accomplished by inserting silica tubes into high-temperature vents. Volcanic gas flows through the tubes and sublimates precipitate on the inner walls in response to the temperature gradient. With decreasing temperature (800–500°C) in the tubes, there are five sublimate z
Authors
Robert B. Symonds
Thermodynamic evaluation and restoration of volcanic gas analyses: An example based on modern collection and analytical methods
Thermodynamic evaluation and restoration procedures are applied to a set of 10 volcanic gas analyses obtained by modern collection and analytical methods. The samples were collected from a vigorously fuming fissure during episode 1 of the Puu Oo eruption of Kilauea Volcano in 1983. A variety of analytical techniques were used to determine the gas compositions. In most samples, the combined amounts
Authors
Terrance M. Gerlach
Volcanic activity in Alaska: September 1991-September 1992
More than 40 historically active volcanic centers, each consisting of one or more volcanoes, are located on the Alaska Peninsula and Aleutian Islands (see map on next page). On average, at least one of these volcanoes erupts each year.
Authors
Game McGimsey
Volcanic gases create air pollution on the Island of Hawai’i
In a handful of molten magma weighing about a pound, there is less than a tenth of an ounce, by weight, of idssolved gas-roughly the same weight as a pinch of table salt. Yet this tiny amount of gas produces spectacular lava foundations hundreds of meters high (see accompanying photograph). The fountain occurs as magma reaches the surface, because dissolved volcanic gases exolve and expand tremend
Authors
J. Sutton, T. Elias
Where lava meets the sea; Kilauea Volcano, Hawaii
Active volcanoes on the island of Hawai'i provide scientists with exceptional opportunities to observe volcanic phenomena at close range. Such an opportunity occurred on November 24, 1992, when geologists from the Hawaiian Volcano Observatory (HVO) witnessed spectacular explosive interactions between lava and seawater on the southeast coast of the island. As seawater invaded submarine conduits tra
Authors
T. N. Mattox