Western Mineral Resources
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| Publications listing | ||
Interests: |
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Hydrothermal alteration of igneous rocks |
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Epithermal gold-silver deposits |
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Cenozoic magmatism and metallogenesis of the northwestern United States |
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Contact: |
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| Telephone: (650) 329-5424
Fax: (650) 329-5491 Email: djohn@usgs.gov |
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Education |
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| 1976 B.S., Earth Sciences, University of California at Santa Cruz
1979 M.S., Geology, Stanford University 1987 Ph.D, Geology, Stanford University |
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Experience |
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| Beginning in 1975, I worked 4 summers in mineral exploration in the western United States. Since 1979, I have worked as a research geologist in the USGS Mineral Resources Team in Menlo Park, CA. My previous work at the USGS has included regional mapping and mineral resource assessments in eastern California and Nevada; detailed mapping and studies of Tertiary volcanism and tectonics of western Nevada; detailed studies of hydrothermal systems related to middle Tertiary magmatism in the central Wasatch Mountains, Utah; detailed studies of several epithermal gold-silver deposits in Nevada; study of the northern Nevada rift; and regional studies of Tertiary epithermal gold-silver deposits in the Great Basin. In these studies, I have used a combination of detailed field mapping and petrographic, geochronologic, geochemical, fluid inclusion, stable isotope, geophysical, and paleomagnetic studies to better understand igneous, tectonic, and hydrothermal histories. I am a former associate editor of Economic Geology and former member of the Council of the Society of Economic Geologists. | ||
Current Activities |
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| I am chief of the Resources and Hazards of Hydrothermal Systems in Cascades Volcanoes and Mineral Systems of the Ancestral and Modern Cenozoic Cascades Arcs and Central California Coast Ranges, Western USA projects and a member of the Metallogeny of the Great Basin and the Updated National Mineral Resource Assessment projects. On these projects my work involves (1) studies of active and recently active hydrothermal systems related to the High Cascades volcanoes in Washington, Oregon, and California (Mount Rainier, Mt. Adams, Lassen Peak); (2) hydrothermal alteration and volcano hazards in the High Cascades (Mount Rainier, Mt. Adams, and Mt. Baker), (3) metallogenesis of the ancestral Tertiary Cascades arc, Washington, Oregon, California and western Nevada, (4) metallogeny of late Tertiary-Quaternary igneous rocks in the northern California Coast Ranges, (5) study of the late Eocene Caetano caldera and related mineral deposits in north-central Nevada, and (6) metallogeny of Cenozoic igneous rocks in northern Nevada. | ||
| Mineral Resources | Eastern / Central / Western / Alaska / Minerals Information |
| Crustal Imaging & Characterization / Spatial Data |
U.S. Department of the Interior |
U.S. Geological Survey
URL: http://minerals.usgs.gov/west/menlo/djohn.htm
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