12748 – 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: 12748

Permit Number: CRLA1994AMDH

Date Received: Jan 01, 1998

Reporting Year: 1994

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

Park-assigned Study Id. # CRLA1994AMDH

Permit Expiration Date: Jan 01, 1998

Permit Start Date: Jan 01, 1998

Study Starting Date: Jan 01, 1994

Study Ending Date: Jan 01, 1994

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:  Field work in 1994 clarified many stratigraphic relationships amoung the lavas from different volcanic centers that make up Mount Mazama. Lava flows and pyrroclastic rocks from five to ten sources can be found in any one caldera wall section. These can be correlated around the caldera and matched with exposures on the flanks of Mount Mazama. A nice example is the Devils Backbone dike and a correlative lava flow on the west slope of the mountain in the drainage of Copeland Creek that extends west of the park boundry, 11 km from the Caldera rim.

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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