Dust and Pleistocene Ice Ages: Eolian Sediments and Climate Change at Ziegler Reservoir, Snowmass Village, Colorado

<p>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. Finegrained 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.</p>

Name thesis:degree_name

M.A.

Level thesis:degree_level

Masters Thesis

Year dc:date.available

2014

Author dc:creator

• Honke, Jeffrey S.

Contributors dc:contributor

• J. Michael Daniels, Ph.D.
• Martin F. Quigley, Ph.D.
• Donald G. Sullivan
• Michael W. Kerwin
• Jeffrey S. Pigati

• Bull Lake
• Dust
• Pinedale
• Rocky Mountains
• Sangamon
• Ziegler Reservoir
• Climate
• Earth Sciences
• Geology

Statement dc:rights

• <p>Copyright is held by the author. User is responsible for all copyright compliance.</p>

Language dc:language

en

Repository record dc:identifier

https://digitalcommons.du.edu/etd/293

OAI identifier oai:identifier

oai:digitalcommons.du.edu:etd-1292