Date of Award

1-1-2014

Document Type

Thesis

Degree Name

M.A.

Department

Geography

First Advisor

J M. Daniels

Second Advisor

Martin F. Quigley

Keywords

Bull Lake, dust, Pinedale, Rocky Mountains, Sangamon, Ziegler Reservoir

Abstract

Author: Jeffrey S. Honke

Title: DUST AND PLEISTOCENE ICE AGES: EOLIAN SEDIMENTS AND CLIMATE CHANGE AT ZIEGLER RESERVOIR, SNOWMASS VILLAGE, COLORADO

Advisor: Dr. J. Michael Daniels

Degree Date: June 2014

The discovery of the Ziegler Reservoir fossil site near Snowmass Village, Colorado presents an opportunity to examine subalpine ecosystem response, during a relatively unknown period, in which climate conditions were similar to present. Fine-grained sediments at Ziegler Reservoir represent continuous deposition between ~140-55 ka (thousand years before present), spanning the close of the Bull Lake glacial period [marine isotope stage (MIS) 6], the Sangamon interglacial (MIS 5) and the early stages of the Pinedale (early Wisconsin) glacial period (MIS 4). Ziegler Reservoir is positioned on top of a ridge, at an elevation of 2705 m, and has a small watershed area (~14 ha), with little evidence of fluvial sediment transport. Particle size distributions, mineralogy, and geochemistry indicate eolian processes were the likely mechanism for deposition of the local, silt-rich and clay-rich sediments that ultimately filled the basin. The presence of clay-rich units (up to three-times more clay than background), is interpreted to represent glacial conditions at two distinct intervals: 1) ~140-134 ka (MIS 6) and 2) ~71-55 ka (MIS 4/3), which correspond to late Bull Lake and early Pinedale glacial periods, respectively. In addition, the absence of clay-rich sediment in the intervening sediments suggests a lack of glacial activity during sub-stages MIS 5d and 5b. In all, the Ziegler Reservoir sedimentary record provides critical information regarding environmental response of high-alpine ecosystems to climate change in the Rocky Mountains during the late Pleistocene.

Provenance

Recieved from ProQuest

Rights holder

Jeffrey Honke

File size

124 p.

File format

application/pdf

Language

en

Discipline

Geology, Paleoclimate science, Geography

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