T356 Pedogenic Minerals as Indicators of Ecosystems: Understanding the Critical Zone through Space and Time (Posters)
Wednesday, 30 October 2013
9:00 AM - 6:30 PM
Hall D
GEOMORPHOLOGY AND GEOLOGIC HISTORY OF SAGEHEN VALLEY, TRUCKEE, CALIFORNIA
Paper number: T356-5
Program: Technical Sessions
Time: 9:00 AM – 6:30 PM
Authors
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Alexander G. WoodUniversity of California Santa Barbara, Santa Barbara, CA
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Kyle MoultonUniversity of California Santa Barbara, Santa Barbara, CA
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Gary L. RainesReno, NV
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Daniel N. LivseyUniversity of California Santa Barbara, Santa Barbara, CA
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Arthur G. SylvesterUniversity of California, Santa Barbara, Santa Barbara, CA
Abstract
Geologic mapping at 1:12 000 of the Sagehen Valley, supported by LIDAR imagery, is used to delimit the age and origin of four terraces along Sagehen Creek in the northern Sierra Nevada of Calfornia. The goal is to better understand the Late Cenozoic geologic history of the valley. Stratigraphy and cross cutting relationships with lava flows and glacial deposits establish a timeline of geologic events. The terraces are numbered one to four from highest to lowest in elevation. Terraces 1 and 2 are overlain by 5.5 million year old pyroxene andesite. Sierran uplift at 3.3 Ma led to the incision of a deep canyon. The Pleistocene Donner Lake glacial deposits overlie terraces 1 and 2, but not terrace 3, providing the upper limit of the age of terrace 3. Terrace 3 is comprised of fluvial sediment that has been incised since 1880 by downcutting of the modern Sagehen Creek.