12734 – 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: 12734

Reporting Year: 1993

Permit Number: CRLA1993AHDP

Current Status: Checked in

Date Received: Jan 01, 1998

Principal Investigator: Charles Bacon, U.S. States Geological Survey, Menlo Park, CA

Park-assigned Study Id. # CRLA1993AHDP

Permit Expiration Date: Jan 01, 1998

Permit Start Date: Jan 01, 1998

Study Starting Date: Jan 01, 1993

Study Ending Date: Jan 01, 1993

Study Status: Completed

Activity Type: Other

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:  A north-south trending normal fault, down to the east, was documented 2 km west of Union Peak. Also in this general area, paleomagnetic data obtained this year by Duane Champion show that the Holocene balistic vents on either side of Castle Point are coeval. Our new mapping indicates that lava flows from these vents lie on latest Pleistocene moraine and are overlain by ignimbrite of the climactic eruption, thereby pinning their age as between about 12,000 and 8,000 years. These are the youngest basaltic vents in the vicinity of Crater Lake.

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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