Michael Clynne
I am currently a Research Geologist at the USGS California Volcano Observatory (CalVO) and fundamentally a field geologist who maps Cascade volcanoes and interprets their eruptive history, geochemistry and petrology.
My primary interests are in using mineralogy, crystal chemistry and rock textures to determine the origin and evolution of magmas erupting at Cascade volcanoes. I am currently the USGS geologist who most versed in geology of the Lassen Volcanic Center and southernmost Cascades volcanoes and the geology of Mount St. Helens. I interface with managers and staff at Lassen Volcanic National Park and Mount St. Helens National Volcanic Monument on geologic and interpretation issues in those parks. I entered the USGS as a student field assistant in 1975 and have been employed there ever since.
I am currently in the final stages of producing a geologic map of Mount St. Helens. The field work is complete and I am writing the materials that will accompany the map. My goal is to understand the complex eruptive history of Mount St. Helens as thoroughly as possible using stratigraphy and geochronology. I and colleagues have added considerable detail to the geologic history framework produced by earlier USGS geologists.
My work at Lassen is at a mature stage. The geologic map of the Lassen Volcanic Center and vicinity describes the geology and eruptive history of the Lassen Volcanic Center and the many smaller volcanoes that surround it. The basic geologic work at Lassen has been used to provide a framework for interpretation of the hydrothermal system and as basis for volcano hazards assessment of the region. A variety of topical studies in collaboration with colleagues include geochronology, geochemistry, isotope geology, petrology, mineral chemistry, physical volcanology, geophysics, tectonics and hydrothermal systems. Some of the geologic processes described at Lassen have guided work at other Cascades volcanoes and the arc as a whole.
Professional Experience
Former associate editor Bulletin of Volcanology
Education and Certifications
Ph.D. University of California-Santa Cruz, 1993
M.S. California State California-San Jose, 1983
B.S. University of California-Santa Cruz, 1976
Affiliations and Memberships*
Geological Society of America
American Geophysical Union
Honors and Awards
Geological Society of America Fellow
Science and Products
Osmium isotope constraints on lower crustal recycling and pluton preservation at Lassen Volcanic Center, CA
Ancient and modern subduction zone contributions to the mantle sources of lavas from the Lassen region of California inferred from Lu-Hf isotopic systematics
Volcano hazards of the Lassen Volcanic National Park area, California
How old is "Cinder Cone"? — Solving a mystery in Lassen Volcanic National Park, California
No abstract available.
Revised age of the Rockland tephra, northern California: Implications for climate and stratigraphic reconstructions in the western United States: Reply
Eruptions of Lassen Peak, California, 1914 to 1917
Geology and geothermal potential of Alid volcanic center, Eritrea, Africa
IGC field trip T312: South cascades arc volcanism, California and southern Oregon
Solubility of NaCl and KCl in aqueous HCl from 20 to 85°C
Solubility of highly soluble salts in aqueous media - Part 1, NaCl, KCl, CaCl2, Na2SO4, and K2SO4 solubilities to 100°C
Non-USGS Publications**
**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.
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Filter Total Items: 46
Osmium isotope constraints on lower crustal recycling and pluton preservation at Lassen Volcanic Center, CA
Osmium isotope compositions of intermediate- to silicic-composition calc-alkaline volcanic rocks from the Lassen volcanic region of the Cascade arc are significantly more radiogenic (γOs=+23 to +224) than typical mantle. These evolved arc rocks in the Lassen region have unradiogenic Sr, Nd, and Pb isotope compositions which overlap with those of contemporaneous mafic lavas. Crystal fractionation oAuthorsGarret L. Hart, Clark M. Johnson, Steven B. Shirey, Michael A. ClynneAncient and modern subduction zone contributions to the mantle sources of lavas from the Lassen region of California inferred from Lu-Hf isotopic systematics
Hafnium isotopic compositions have been determined on a suite of calc-alkaline and high-alumina-olivine tholeiitic lavas from the Lassen region of California and are used, in conjunction with previously published mineralogical, geochemical, and isotopic data, to constrain their petrogenesis. Positive correlation between εHf values and geochemical indices of the modern subduction component indicateAuthorsL. E. Borg, Janne Blichert-Toft, Michael A. ClynneVolcano hazards of the Lassen Volcanic National Park area, California
No abstract available.AuthorsMichael A. Clynne, Robert L. Christiansen, C.D. Miller, P.H. Stauffer, James W. HendleyHow old is "Cinder Cone"? — Solving a mystery in Lassen Volcanic National Park, California
No abstract available.
AuthorsMichael A. Clynne, Duane E. Champion, Deborah A. Trimble, James W. Hendley, Peter H. StaufferRevised age of the Rockland tephra, northern California: Implications for climate and stratigraphic reconstructions in the western United States: Reply
Sarna-Wojcicki suggests that the 40Ar/39Ar age of 614 ± 8 ka for the Rockland tephra (Lanphere et al., 1999) is too old because of the presence of xenocrystic plagioclase. The Rockland tephra is indeed full of lithic debris that can be seen at any well-exposed outcrop of ash-flow or air-fall deposits. In order to minimize contamination, we selected pumice lumps known to be representative of the RoAuthorsMarvin A. Lanphere, Duane E. Champion, Michael A. Clynne, L. J. Patrick MufflerEruptions of Lassen Peak, California, 1914 to 1917
On May 22, 1915, an explosive eruption at Lassen Peak, California, the southernmost active volcano in the Cascade Range, devastated nearby areas and rained volcanic ash as far away as 200 miles to the east. This explosion was the most powerful in a 1914–17 series of eruptions that were the last to occur in the Cascades before the 1980 eruption of Mount St. Helens, Washington. Recent work by scientAuthorsMichael A. Clynne, Robert L. Christiansen, Tracey J. Felger, Peter H. Stauffer, James W. HendleyGeology and geothermal potential of Alid volcanic center, Eritrea, Africa
Alid volcanic center, a 700-meter-tall mountain in Eritrea, northeast Africa, straddles the axis of an active crustal-spreading center called the Danakil Depression. Boiling-temperature fumaroles are common on Alid, and their gas compositions indicate a reservoir temperature of at least 250 ??C. The history of volcanism and the high reservoir temperature indicated by the Alid fumarole gases suggesAuthorsMichael A. Clynne, Wendell A. Duffield, Robert O. Fournier, Leake W. Giorgis, Cathy J. Janik, Gabreab Kahsai, Jacob Lowenstern, Kidane W. Mariam, James G. Smith, Theoderos TesfaiIGC field trip T312: South cascades arc volcanism, California and southern Oregon
No abstract available.AuthorsL. J. Patrick Muffler, Charles R. Bacon, Robert L. Christiansen, Michael A. Clynne, Julie M. Donnelly-Nolan, Cheryl Miller, David R. Sherrod, J.C. SmithSolubility of NaCl and KCl in aqueous HCl from 20 to 85°C
The solubilities of NaCl and KCl in aqueous HCl solutions were determined from 20 to 85°C at concentrations ranging from 0 to 20 g of HCl/100 g of solution. Equations are given that describe the solubilities over the range of conditions studied. For NaCl and KCl respectively measured solubilities show an average deviation from these equations of ??0.10 and ??0.08 g/100 g of saturated solution.AuthorsRobert W. Potter, Michael A. ClynneSolubility of highly soluble salts in aqueous media - Part 1, NaCl, KCl, CaCl2, Na2SO4, and K2SO4 solubilities to 100°C
A modified visual method for determining the solubility of highly soluble salts in aqueous media up to 100° C is presented. The solubilities of NaCl, KCl, CaCl2, Na2SO4, and K2SO4 were determined up to 100° C. The tabulated experimental data and the fitted equations describing the data indicate that the previous literature data for the solubility of these salts were generally high by 0.05 to 2.0AuthorsRobert W. Potter, Michael A. ClynneNon-USGS Publications**
**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.
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*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