12839 – Volcanic Evolution of the Crater Lake Region

Investigator’s Annual Reports (IAR’s) for Crater Lake National Park

Volcanic Evolution of the Crater Lake Region


Report Number: 12839

Reporting Year: 1998

Permit Number: CRLA1998BACO

Date Received: Jan 01, 1999

Principal Investigator: Charles Bacon, U.S. Geological Survey, U.S.G.S., Menlo park, CA

Additional investigator(s): Duane Champion

Park-assigned Study Id. # CRLA1998BACO

Permit Expiration Date: Jan 01, 2000

Permit Start Date: Jan 01, 1999

Study Starting Date: Jan 01, 1997

Study Ending Date: Jan 01, 1999

Study Status: Completed

Activity Type: Research

Subject/Discipline: Geology / General

Objectives: To document the growth and evolution of Mount Mazama, the volcanic complex in which Crater Lake caldera lies, in order to define processes that led to an accumulation of a large volume of silicic magma in the upper crust. Secondary goals are to further knowledge of catastrophic eruptions, such as the one that resulted in the collapse of the caldera.

Findings and Status:  The 1:24,000 scale geologic map of Mount Mazama and Crater Lake caldera is being prepared for publication. Digital files of the geologic map and all eleven geologic panoramas of the caldera walls are being edited in ArcInfo. These will be published in color and the map also will be released in digital form. A paper on the slip rate on the West Klamath Lake fault zone near Crater Lake was accepted for publication in the journal, “Geology”. Renee Bourgeois, University of Oregon, completed her Masters thesis project on the Cleetwood pumice fall deposit under the direction of Prof. K.V. Cashman and C.R. Bacon, and gave a poster presentation at the Fall meeting of the American Geophysical Union in San Francisco. Dr. Charles Mandeville, American Museum of Natural History, gave a talk at the Fall AGU meeting on sulfur isotope determinations in volcanic rocks from Crater Lake. Dr. Marvin Lanphere, USGS, and co-workers measured several new K-Ar ages of volcanic rocks from Crter Lake, bringing the total to 106. These data will be published in a companion paper to the geologic map. No field work was conducted in 1998 and no new specimens were collected.

For this study, were one or more specimens collected and removed from the park but not destroyed during analyses? No

Funding provided this reporting year by NPS: 0

Funding provided this reporting year by other sources: 0

Full name of college or university:  n/a

Annual funding provided by NPS to university or college this reporting year: 0


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