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.
","abstract_html":"<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>","abstract_has_math":false,"creators":["Honke, Jeffrey S."],"institution":null,"degree_name":"M.A.","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["J. Michael Daniels, Ph.D.","Martin F. Quigley, Ph.D.","Donald G. Sullivan","Michael W. Kerwin","Jeffrey S. Pigati"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-06-01T07:00:00Z","date_published":"2014-06-01T07:00:00Z","updated_at":"2026-07-24T02:02:19Z","subjects":["Bull Lake","Dust","Pinedale","Rocky Mountains","Sangamon","Ziegler Reservoir","Climate","Earth Sciences","Geology"],"languages":["en"],"rights":["Copyright is held by the author. User is responsible for all copyright compliance.
"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://digitalcommons.du.edu/etd/293","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["J. Michael Daniels, Ph.D.","Martin F. Quigley, Ph.D.","Donald G. Sullivan","Michael W. Kerwin","Jeffrey S. Pigati"]},{"key":"dc:creator","label":"Author","values":["Honke, Jeffrey S."]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2001-01-01T08:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["M.A."]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Bull Lake","Dust","Pinedale","Rocky Mountains","Sangamon","Ziegler Reservoir","Climate","Earth Sciences","Geology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright is held by the author. User is responsible for all copyright compliance.
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"]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Dust and Pleistocene Ice Ages: Eolian Sediments and Climate Change at Ziegler Reservoir, Snowmass Village, Colorado"]}]}],"canonical_facts":{"dc:contributor":["J. Michael Daniels, Ph.D.","Martin F. Quigley, Ph.D.","Donald G. Sullivan","Michael W. Kerwin","Jeffrey S. Pigati"],"dc:creator":["Honke, Jeffrey S."],"dc:date.available":["2001-01-01T08:00:00Z"],"dc:description.abstract":["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.
"],"dc:format":["application/pdf"],"dc:identifier":["https://digitalcommons.du.edu/etd/293"],"dc:language":["en"],"dc:rights":["Copyright is held by the author. User is responsible for all copyright compliance.
"],"dc:subject":["Bull Lake","Dust","Pinedale","Rocky Mountains","Sangamon","Ziegler Reservoir","Climate","Earth Sciences","Geology"],"dc:title":["Dust and Pleistocene Ice Ages: Eolian Sediments and Climate Change at Ziegler Reservoir, Snowmass Village, Colorado"],"thesis:degree_level":["Masters Thesis"],"thesis:degree_name":["M.A."]},"updated_at":"2026-07-24T02:02:19Z"}