Showing papers by "William I. Rose published in 1986"

Rates of sulfur dioxide and particle emissions from White Island volcano, New Zealand, and an estimate of the total flux of major gaseous species

Abstract: Airborne correlation spectrometry (COSPEC) was used to measure the rate of SO2 emission at White Island on three dates, i.e., November 1983, 1230 ± 300 t/d; November 1984, 320 ± 120 t/d; and January 1985, 350 ± 150 t/d (t = metric tons). The lower emission rates are likely to reflect the long-term emission rates, whereas the November 1983 rate probably reflects conditions prior to the eruption of December 1983. The particle flux in the White Island plume, as determined with a quartz crystal microbalance/cascade in November 1983, was 1.3 t/d, unusually low for volcanic plumes. The observed plume particles, as shown from scanning electron microscopy, include halite, native sulfur, and silicates and are broadly similar to other volcanic plumes. Gas analyses from high-temperature volcanic fumaroles collected from June 1982 through November 1984 werde used together with the COSPEC data to estimate the flux of other gas species from White Island. The rates estimated are indicative of the long-term volcanic emission, i.e., 8000–9000 t/d H2O, 900–1000 t/d CO2, 70–80 t/d HCl, 1.5–2 t/d HF, and about 0.2 t/d NH3. The long-term thermal power output at White Island is estimated at about 400 MW.

Dynamic deformation of volcanic ejecta from the Toba caldera: Possible relevance to Cretaceous/Tertiary boundary phenomena

Abstract: Plagioclase and biotite phenocrysts in ignimbrites erupted from the Toba caldera, Sumatra, show microstructures and textures indicative of shock stress levels higher than 10 GPa. Strong dynamic deformation has resulted in intense kinking in biotite and, with increasing shock intensity, the development of plagioclase of planar features, shock mosaicism, incipient recrystallization, and possible partial melting. Microstructures in quartz indicative of strong shock deformation are rare, however, and many shock lamellae, if formed, may have healed during post-shock residence in the hot ignimbrite; they might be preserved in ash falls. Peak shock stresses from explosive silicic volcanism and other endogenous processes may be high and if so would obviate the need for extraterrestrial impacts to produce all dynamically deformed structures, possibly including shock features observed near the Cretaceous/Tertiary boundary. 38 references, 3 figures.

Rapid, high-quality major and trace element analysis of powdered rock by X-ray fluorescence spectrometry

Abstract: Rapid and high-quality major and trace element data can be obtained by automated x-ray fluorescence (XRF) analysis of pressed rock powder pellets. The sample preparation procedure is simple, quick and can be done well with minimal supervision. Analysis of the rock pellet for 22 elements requires about 1 h of machine time. The system is calibrated by use of multiple international rock standards and employs a ratio standard for all measurements. Most calibrations are simple linear fits between intensity and concentration. The precision of the major element results are generally better than ±1% of the amount determined, whereas the trace element precisions are generally less than 5%, except when the value determined is close to the detection limit. Accuracies are comparable to those of other published XRF rock analysis procedures.

Fluxes, sizes, morphology and compositions of particles in the MT. Erebus volcanic plume, December 1983

Abstract: Use of an airborne quartz crystal microbalance cascade impactor instrument together with a correlation spectrometer has allowed the flux of particles and their size distribution to be determined at Mount Erebus. The plume contributes 21±3 metric tomnes/day of aerosol particles to the Antarctic upper troposphere. The aerosol particles consist of larger (5–25 μm) particles of elemental sulfur and silica, a middle sized group of iron oxides and smaller particles (less than 1 μm) of complex liquids. Unlike many volcanic plumes, the Erebus plume has only a small amount of sulfate particles. The concentrations of particles in the Erebus plumes was 70–370 μm/m3. Limited sampling of the Antarctic atmosphere at 8 km altitude but hundreds of km away from Erebus obtained a few large particles of sulfur and silicates, suggesting a similarity with the Erebus plume. The fallout of these particles occurs slowly over a broad area of the Antarctic continent.

Partitioning of Gold in Young Calc-Alkalic Volcanic Rocks from Guatemala

Abstract: Gold analyses of whole rock, mineral, and groundmass of seven calc-alkalic volcanic rocks (basalt to rhyolite) show that gold is less abundant in the dominant phenocrystic phases than in the whole rock; groundmass concentrations are also lower than whole rock. Crystal-liquid partition coefficients are <1 for plagioclase and hornblende, and about 1 for olivine, pyroxene, magnetite, and biotite. If only the principal phases are considered, the bulk gold partition coefficient is typically <1, yet gold seems to be depleted rather than enriched in many evolved magmas. A significant proportion of gold in these rocks is in neither the groundmass nor the dominant phenocrysts but instead is contained in tiny sulflde blebs that are found in these rocks. During crystallization the continual separation of a sulflde phase that concentrates gold is consistent with compatible gold behavior and petrography. Further data is needed to evaluate this hypothesis.