Wes Hildreth (Former Employee)
Science and Products
Filter Total Items: 70
A Nd, Sr and O isotopic investigation into the causes of chemical and isotopic zonation in the Bishop Tuff, California A Nd, Sr and O isotopic investigation into the causes of chemical and isotopic zonation in the Bishop Tuff, California
The Bishop Tuff represents a single eruption of chemically zoned rhyolitic magma. Six whole rock samples spanning the compositional and temperature range yield initial87Sr/86Sr of 0.7060–0.7092 andδ18O of 5.9–10.3‰. Six constituent sanidines yield smaller ranges of initial87Sr/86Sr of 0.7061–0.7069 andδ18O of 6.7–7.9. In contrast143Nd/144Nd ratios for the six whole rocks and two...
Authors
A. N. Halliday, A.E. Fallick, J. Hutchinson, W. Hildreth
The isotopic and chemical evolution of Mount St. Helens The isotopic and chemical evolution of Mount St. Helens
Isotopic and major and trace element analysis of nine samples of eruptive products spanning the history of the Mt. St. Helens volcano suggest three different episodes; (1) 40,000–2500 years ago: eruptions of dacite with εNd = +5, εSr = −10, variable δ18O,206Pb/204Pb ∼ 18.76, Ca/Sr ∼ 60, Rb/Ba ∼ 0.1, La/Yb ∼ 18, (2) 2500-1000 years ago: eruptions of basalt, andesite and dacite with εNd =...
Authors
A. N. Halliday, A.E. Fallick, A.P. Dickin, A.B. Mackenzie, W.E. Stephens, W. Hildreth
The compositionally zoned eruption of 1912 in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska The compositionally zoned eruption of 1912 in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska
On June 6–8, 1912, ∼ 15 km3 of magma erupted from the Novarupta caldera at the head of the Valley of Ten Thousand Smokes (VTTS), producing ∼ 20 km3 of air-fall tephra and 11–15 km3 of ash-flow tuff within ∼ 60 hours. Three discrete periods of ash-fall at Kodiak correlate, respectively, with Plinian tephra layers designated A, CD, and FG by Curtis (1968) in the VTTS. The ash-flow...
Authors
W. Hildreth
Large partition coefficients for trace elements in high-silica rhyolites Large partition coefficients for trace elements in high-silica rhyolites
The partitioning of 25 trace elements between high-silica rhyolitic glass and unzoned phenocrysts of potassic and sodic sanidine, biotite, augite, ferrohedenbergite, hypersthene, fayalite, titanomagnetite, ilmenite, zircon, and allanite has been determined by INAA on suites of samples from the mildly peralkaline lavas and tuff of the Sierra La Primavera, Mexico, and the metaluminous...
Authors
G. Mahood, W. Hildreth
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
A Nd, Sr and O isotopic investigation into the causes of chemical and isotopic zonation in the Bishop Tuff, California A Nd, Sr and O isotopic investigation into the causes of chemical and isotopic zonation in the Bishop Tuff, California
The Bishop Tuff represents a single eruption of chemically zoned rhyolitic magma. Six whole rock samples spanning the compositional and temperature range yield initial87Sr/86Sr of 0.7060–0.7092 andδ18O of 5.9–10.3‰. Six constituent sanidines yield smaller ranges of initial87Sr/86Sr of 0.7061–0.7069 andδ18O of 6.7–7.9. In contrast143Nd/144Nd ratios for the six whole rocks and two...
Authors
A. N. Halliday, A.E. Fallick, J. Hutchinson, W. Hildreth
The isotopic and chemical evolution of Mount St. Helens The isotopic and chemical evolution of Mount St. Helens
Isotopic and major and trace element analysis of nine samples of eruptive products spanning the history of the Mt. St. Helens volcano suggest three different episodes; (1) 40,000–2500 years ago: eruptions of dacite with εNd = +5, εSr = −10, variable δ18O,206Pb/204Pb ∼ 18.76, Ca/Sr ∼ 60, Rb/Ba ∼ 0.1, La/Yb ∼ 18, (2) 2500-1000 years ago: eruptions of basalt, andesite and dacite with εNd =...
Authors
A. N. Halliday, A.E. Fallick, A.P. Dickin, A.B. Mackenzie, W.E. Stephens, W. Hildreth
The compositionally zoned eruption of 1912 in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska The compositionally zoned eruption of 1912 in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska
On June 6–8, 1912, ∼ 15 km3 of magma erupted from the Novarupta caldera at the head of the Valley of Ten Thousand Smokes (VTTS), producing ∼ 20 km3 of air-fall tephra and 11–15 km3 of ash-flow tuff within ∼ 60 hours. Three discrete periods of ash-fall at Kodiak correlate, respectively, with Plinian tephra layers designated A, CD, and FG by Curtis (1968) in the VTTS. The ash-flow...
Authors
W. Hildreth
Large partition coefficients for trace elements in high-silica rhyolites Large partition coefficients for trace elements in high-silica rhyolites
The partitioning of 25 trace elements between high-silica rhyolitic glass and unzoned phenocrysts of potassic and sodic sanidine, biotite, augite, ferrohedenbergite, hypersthene, fayalite, titanomagnetite, ilmenite, zircon, and allanite has been determined by INAA on suites of samples from the mildly peralkaline lavas and tuff of the Sierra La Primavera, Mexico, and the metaluminous...
Authors
G. Mahood, W. Hildreth
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