A Miocene to Pleistocene climate and elevation record of the Sierra Nevada (California)

PNAS
By: , and 

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Abstract

Orographic precipitation of Pacific-sourced moisture creates a rain shadow across the central part of the Sierra Nevada (California) that contrasts with the southern part of the range, where seasonal monsoonal precipitation sourced to the south obscures this rain shadow effect. Orographic rainout systematically lowers the hydrogen isotope composition of precipitation (δDppt) and therefore δDppt reflects a measure of the magnitude of the rain shadow. Hydrogen isotope compositions of volcanic glass (δDglass) hydrated at the earth's surface provide a unique opportunity to track the elevation and precipitation history of the Sierra Nevada and adjacent Basin and Range Province. Analysis of 67 well dated volcanic glass samples from widespread volcanic ash-fall deposits located from the Pacific coast to the Basin and Range Province demonstrates that between 0.6 and 12.1 Ma the hydrogen isotope compositions of meteoric water displayed a large (>40‰) decrease from the windward to the leeward side of the central Sierra Nevada, consistent with the existence of a rain shadow of modern magnitude over that time. Evidence for a Miocene-to-recent rain shadow of constant magnitude and systematic changes in the longitudinal climate and precipitation patterns strongly suggest that the modern first-order topographic elements of the Sierra Nevada characterized the landscape over at least the last 12 million years.

Study Area

Publication type Article
Publication Subtype Journal Article
Title A Miocene to Pleistocene climate and elevation record of the Sierra Nevada (California)
Series title PNAS
DOI 10.1073/pnas.0708811105
Volume 105
Issue 19
Year Published 2009
Language English
Publisher National Academy of Sciences
Description 6 p.
First page 6819
Last page 6824
Country United States
State California, Nevada
Other Geospatial Sierra Nevada Mountains
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