Graduation Date

Fall 2022

Document Type



Master of Science degree with a major in Environmental Systems, option Geology

Committee Chair Name

Dr. Laura Levy

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Dr. Melanie Michalak

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Dr. Brandon Browne

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories



The Klamath Mountains are a 233-km-long (north to south) mountain range located in northern California that shows extensive geomorphic evidence of Pleistocene glaciation. Within the Klamath’s there are many highland lakes, which record evidence of glacial deposition, one of which is Picayune Lake. Lake sediment data collected from Picayune Lake offers insights into the glaciation, and broader depositional history of the Picayune Lake Valley, as well as the climate history of the Klamath Mountains region. I measured magnetic susceptibility, loss on ignition, and grain size in sediment cores and used radiocarbon dating to determine a chronology of glacier fluctuations in the valley. The data show that deglaciation occurred as recently as 11,340 ± 660 cal yr BP and as late as 13,610 ± 120 cal yr BP. Middle Holocene records from Picayune Lake record an inwash of coarse sediments at 7140 ± 690 cal yr BP, as well as deposition of an unsourced tephra at 5640 ± 310 cal yr BP. Late Holocene records from Picayune Lake record layers of coarse sediment at 2490 ± 450 cal yr BP and 1530 ± 220 cal yr BP that I interpret as sediment being washed off the surrounding landscape and deposited into the lake. A second tephra was found at 870 ± 200 cal yr BP, which may have originated from the Little Glass Mountain eruption in northeastern California. The sedimentological record shows no evidence of late Holocene glacier renewal at this site, similar to other low elevation cirques in the region.

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