Wes Hildreth (Former Employee)
Science and Products
Filter Total Items: 70
Complex proximal deposition during the Plinian eruptions of 1912 at Novarupta, Alaska Complex proximal deposition during the Plinian eruptions of 1912 at Novarupta, Alaska
Proximal (
Authors
Bruce F. Houghton, C. J. N. Wilson, J. Fierstein, W. Hildreth
Rear-arc vs. arc-front volcanoes in the Katmai reach of the Alaska Peninsula: A critical appraisal of across-arc compositional variation Rear-arc vs. arc-front volcanoes in the Katmai reach of the Alaska Peninsula: A critical appraisal of across-arc compositional variation
Physical and compositional data and K-Ar ages are reported for 14 rear-arc volcanoes that lic 11-22 km behind the narrowly linear volcanic front defined by the Mount Katmai-to-Devils Desk chain on the Alaska Peninsula. One is a 30-km3 stratocone (Mount Griggs; 51-63% SiO2) active intermittently from 292 ka to Holocene. The others are monogenetic cones, domes, lava flows, plugs, and maars...
Authors
W. Hildreth, J. Fierstein, D. F. Siems, J. R. Budahn, J. Ruiz
Rhyodacites of Kulshan caldera, North Cascades of Washington: Postcaldera lavas that span the Jaramillo Rhyodacites of Kulshan caldera, North Cascades of Washington: Postcaldera lavas that span the Jaramillo
Kulshan caldera (4.5×8 km), at the northeast foot of Mount Baker, is filled with rhyodacite ignimbrite (1.15 Ma) and postcaldera lavas and is only the third Quaternary caldera identified in the Cascade arc. A gravity traverse across the caldera yields a steep-sided, symmetrical, complete Bouguer anomaly of −16 mGal centered over the caldera. Density considerations suggest that the...
Authors
W. Hildreth, M. A. Lanphere, D.E. Champion, J. Fierstein
Geochronology and eruptive history of the Katmai volcanic cluster, Alaska Peninsula Geochronology and eruptive history of the Katmai volcanic cluster, Alaska Peninsula
In the Katmai district of the Alaska Peninsula, K–Ar and 40Ar/39Ar ages have been determined for a dozen andesite–dacite stratocones on the arc front and for 11 rear-arc volcanoes, 10 of which are monogenetic. Tied to mapping and stratigraphic studies, our dating emphasized proximal basal lavas that rest on basement rocks, in order to estimate ages of inception of each polygenetic cone...
Authors
Wes Hildreth, Marvin A. Lanphere, Judy Fierstein
Eruptive history and geochronology of the Mount Baker volcanic field, Washington Eruptive history and geochronology of the Mount Baker volcanic field, Washington
Mount Baker, a steaming, ice-mantled, andesitic stratovolcano, is the most conspicuous component of a multivent Quaternary volcanic field active almost continuously since 1.3 Ma. More than 70 packages of lava flows and ~110 dikes have been mapped, ???500 samples chemically analyzed, and ~80 K-Ar and 40Ar/39Ar ages determined. Principal components are (1) the ignimbrite-filled Kulshan...
Authors
W. Hildreth, J. Fierstein, M. Lanphere
New osmium isotope evidence for intracrustal recycling of crustal domains with discrete ages New osmium isotope evidence for intracrustal recycling of crustal domains with discrete ages
New 187Os/188Os ratios of Quaternary Mount Adams volcanic rocks from the Cascade arc in southern Washington vary by >300% (187Os/188Os = 0.165-0.564) and fall into high (>0.319) and low (0.166 to 0.281) groups of 187Os/188Os ratios that are substantially more radiogenic than mantle values. These Os isotope compositions and groupings are interpreted to reflect recycling of discrete...
Authors
G.L. Hart, C.M. Johnson, W. Hildreth, S.B. Shirey
Non-USGS Publications**
Hildreth, W., 1976, Death Valley Geology: Death Valley Natural History Association, Furnace Creek, CA, 64 p.
Ewart, A., Hildreth, W., and Carmichael, I.S. E., 1975, Quaternary acid magma in New Zealand: Contributions to Mineralogy and Petrology, v. 51, p. 1–27.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
Filter Total Items: 70
Complex proximal deposition during the Plinian eruptions of 1912 at Novarupta, Alaska Complex proximal deposition during the Plinian eruptions of 1912 at Novarupta, Alaska
Proximal (
Authors
Bruce F. Houghton, C. J. N. Wilson, J. Fierstein, W. Hildreth
Rear-arc vs. arc-front volcanoes in the Katmai reach of the Alaska Peninsula: A critical appraisal of across-arc compositional variation Rear-arc vs. arc-front volcanoes in the Katmai reach of the Alaska Peninsula: A critical appraisal of across-arc compositional variation
Physical and compositional data and K-Ar ages are reported for 14 rear-arc volcanoes that lic 11-22 km behind the narrowly linear volcanic front defined by the Mount Katmai-to-Devils Desk chain on the Alaska Peninsula. One is a 30-km3 stratocone (Mount Griggs; 51-63% SiO2) active intermittently from 292 ka to Holocene. The others are monogenetic cones, domes, lava flows, plugs, and maars...
Authors
W. Hildreth, J. Fierstein, D. F. Siems, J. R. Budahn, J. Ruiz
Rhyodacites of Kulshan caldera, North Cascades of Washington: Postcaldera lavas that span the Jaramillo Rhyodacites of Kulshan caldera, North Cascades of Washington: Postcaldera lavas that span the Jaramillo
Kulshan caldera (4.5×8 km), at the northeast foot of Mount Baker, is filled with rhyodacite ignimbrite (1.15 Ma) and postcaldera lavas and is only the third Quaternary caldera identified in the Cascade arc. A gravity traverse across the caldera yields a steep-sided, symmetrical, complete Bouguer anomaly of −16 mGal centered over the caldera. Density considerations suggest that the...
Authors
W. Hildreth, M. A. Lanphere, D.E. Champion, J. Fierstein
Geochronology and eruptive history of the Katmai volcanic cluster, Alaska Peninsula Geochronology and eruptive history of the Katmai volcanic cluster, Alaska Peninsula
In the Katmai district of the Alaska Peninsula, K–Ar and 40Ar/39Ar ages have been determined for a dozen andesite–dacite stratocones on the arc front and for 11 rear-arc volcanoes, 10 of which are monogenetic. Tied to mapping and stratigraphic studies, our dating emphasized proximal basal lavas that rest on basement rocks, in order to estimate ages of inception of each polygenetic cone...
Authors
Wes Hildreth, Marvin A. Lanphere, Judy Fierstein
Eruptive history and geochronology of the Mount Baker volcanic field, Washington Eruptive history and geochronology of the Mount Baker volcanic field, Washington
Mount Baker, a steaming, ice-mantled, andesitic stratovolcano, is the most conspicuous component of a multivent Quaternary volcanic field active almost continuously since 1.3 Ma. More than 70 packages of lava flows and ~110 dikes have been mapped, ???500 samples chemically analyzed, and ~80 K-Ar and 40Ar/39Ar ages determined. Principal components are (1) the ignimbrite-filled Kulshan...
Authors
W. Hildreth, J. Fierstein, M. Lanphere
New osmium isotope evidence for intracrustal recycling of crustal domains with discrete ages New osmium isotope evidence for intracrustal recycling of crustal domains with discrete ages
New 187Os/188Os ratios of Quaternary Mount Adams volcanic rocks from the Cascade arc in southern Washington vary by >300% (187Os/188Os = 0.165-0.564) and fall into high (>0.319) and low (0.166 to 0.281) groups of 187Os/188Os ratios that are substantially more radiogenic than mantle values. These Os isotope compositions and groupings are interpreted to reflect recycling of discrete...
Authors
G.L. Hart, C.M. Johnson, W. Hildreth, S.B. Shirey
Non-USGS Publications**
Hildreth, W., 1976, Death Valley Geology: Death Valley Natural History Association, Furnace Creek, CA, 64 p.
Ewart, A., Hildreth, W., and Carmichael, I.S. E., 1975, Quaternary acid magma in New Zealand: Contributions to Mineralogy and Petrology, v. 51, p. 1–27.
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government