Publications

Hydrothermal alteration at Mount Rainier waxed and waned over the 500,000-year episodic growth of the edifice. Hydrothermal minerals and their stable-isotope compositions in samples collected from outcrop and as clasts from Holocene debris-flow deposits identify three distinct hypogene argillic/advanced argillic hydrothermal environments: magmatic-hydrothermal, steam-heated, and magmatic steam (fu

Before the 1991–1992 activity, a large andesite lava dome belonging to the penultimate Pinatubo eruptive period (Buag ∼ 500 BP) formed the volcano summit. Buag porphyritic andesite contains abundant amphibole-bearing microgranular enclaves of basaltic–andesite composition. Buag enclaves have lower K2O and incompatible trace element (LREE, U, Th) contents than mafic pulses injected in the Pinatubo

The 1883 eruption of Augustine Volcano produced a tsunami when a debris avalanche traveled into the waters of Cook Inlet. Older debris avalanches and coeval paleotsunami deposits from sites around Cook Inlet record several older volcanic tsunamis. A debris avalanche into the sea on the west side of Augustine Island ca. 450 years ago produced a wave that affected areas 17 m above high tide on Augus

Mount St. Helens began a dome-building eruption in September 2004 after nearly two decades of quiescence. Dome growth was initially robust, became more sluggish with time, and ceased completely in late January 2008. The volcano has been quiet again since January 2008. Professional Paper 1750 describes the first 1 1/2 years of this eruptive activity, chiefly from September 2004 until December 2

Good stewardship of our Nation's natural resources demands that the extraction of exploitable, minable ore deposits be conducted in harmony with the protection of the environment, a dilemma faced by many land and water management agencies in the Nation's mining areas. As ore is mined, milled, and sent to the smelter, it leaves footprints where it has been in the form of residual trace metals. Ofte

The Alaska Volcano Observatory (AVO) responded to eruptions, possible eruptions, and volcanic unrest at or near nine separate volcanic centers in Alaska during 2006. A significant explosive eruption at Augustine Volcano in Cook Inlet marked the first eruption within several hundred kilometers of principal population centers in Alaska since 1992. Glaciated Fourpeaked Mountain, a volcano thought to

No abstract available.

The geysers of Yellowstone National Park, United States, attract millions of visitors each year, and their eruption dynamics have been the subject of extensive research for more than a century. Although many of the fundamental aspects associated with the dynamics of geyser eruptions have been elucidated, the relationship between external forcing (Earth tides, barometric pressure, and precipitation

Magmatic differentiation helps produce the chemical and petrographic diversity of terrestrial rocks. The extent to which magmatic differentiation fractionates nonradiogenic isotopes is uncertain for some elements. We report analyses of iron isotopes in basalts from Kilauea Iki lava lake, Hawaii. The iron isotopic compositions (56Fe/54Fe) of late-stagemeltveins are 0.2 permil (per thousand) greater

Yellowstone National Park, rimmed by a crescent of older mountainous terrain, has at its core the Quaternary Yellowstone Plateau, an undulating landscape shaped by forces of volcanism, tectonism, and later glaciation. Its spectacular hydrothermal systems cap this landscape. From 1997 through 2003, the United States Geological Survey Mineral Resources Program conducted a multidisciplinary project o

Behind the single-file chain of stratovolcanoes on the Alaska Peninsula, independent rear-arc vents for mafic magmas are uncommon, and for silicic magmas rarer still. We report here the characteristics, compositions, and ages of two andesite-dacite dome clusters and of several nearby basaltic units, all near Becharof Lake and 15 to 20 km behind the volcanic front. Blue Mountain consists of 13 dome

Radiocarbon-dated volcanic mass-flow deposits on the southeast flank of Mount Spurr in south-central Alaska provide strong evidence for the timing of large-scale destruction of the south flank of the volcano by sector collapse at 4,769^ndash;4,610 yr B.P. The sector collapse created an avalanche caldera and produced an ~1-km3-volume clay-rich debris avalanche that flowed into the glacially scoured