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Date Permissions Signed

5-18-2018

Date of Award

Winter 2006

Document Type

Masters Thesis

Degree Name

Master of Science (MS)

Department

Geology

First Advisor

Clark, Douglas H., 1961-

Second Advisor

Steig, Eric

Third Advisor

Babcock, R. Scott (Randall Scott)

Abstract

Glaciers are sensitive and detailed recorders of changes in local, regional, and global climate. Stable isotope variations reflect seasonal temperature changes, physical stratigraphy relates to net precipitation, and trace element concentrations mark seasonal surfaces in the ice. Previous studies have largely focused on polar ice cores because cold, dry conditions in such locations are ideal for preserving ice stratigraphy. Conversely, low-latitude alpine glaciers have been generally ignored because warmer, wetter conditions in them have been presumed to destroy or obscure the original stable isotope stratigraphy. Here, I evaluate the potential to obtain viable environmental records from an ice core of Palisade Glacier Sierra Nevada, California. A shallow, 6-m ice core drilled in the accumulation zone in late summer 2003 was analyzed at ~10-cm intervals for stable isotopes (O16/O18 and D/H) and trace element concentrations. Five stable-isotope maxima and minima couplets occur in the ice core, varying from -16.7 to -14 0/00 (δ 18O and -133 to -1110/00(δ D). The isotope values follow the global meteoric water line, indicating minimal post-depositional disruption of the ice. Maxima in six representative trace-elements (Al, Pb, Mn, V, Ba, Sr) correspond well to those in the isotope records. The covariance of stable-isotopes and trace-elements indicate that the original chemical stratigraphy is preserved in the ice core. These results show that the ice core contains at least 5 years of ice accumulation. Analyses of excess Pb and of precipitation and temperature records from a nearby weather station indicate these 5 years most likely accumulated between 1992 and 1998, and that annual layer thicknesses average about 1 m. This interpretation, combined with the substantial dust band at the surface of the ice core indicate that the five years of accumulation after 1998 (all of which were below-average snowfall) were lost to ablation. Thus, despite five years of net ice loss at the site due to surface melt, the isotopic and elemental stratigraphy is still preserved. The important implication of this finding is that ice in such temperate alpine glaciers appears to be a more robust archive of paleoclimatic information than previously recognized. Furthermore, although the ice core retrieved from the Palisade Glacier likely contains significant gaps, retrieval of a core to bedrock will likely provide the most complete ice core record of paleoclimate data available in the Sierra Nevada.

Type

Text

Keywords

Temperate alpine glaciers, Paleoclimatic information, Ice core records

Publisher

Western Washington University

OCLC Number

1061559106

Subject – LCSH

Glaciers--Environmental aspects--California--Inyo County; Climatic changes--California--Inyo County

Geographic Coverage

Palisade Glacier (Calif); Inyo County (Calif.)

Format

application/pdf

Genre/Form

masters theses

Language

English

Rights

Copying of this document in whole or in part is allowable only for scholarly purposes. It is understood, however, that any copying or publication of this thesis for commercial purposes, or for financial gain, shall not be allowed without the author's written permission.

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