Carbon-14 Plant Evidence of mid-Holocene Quelccaya Ice Cap Margin Fluctuations

• Main Author: Stahl, Henry
• Other Authors: Thompson, Lonnie
• Format: Thesis
• Language: English
• Published: The Ohio State University 2017
• Subjects: radiocarbon; plant; ice; Quelccaya; Holocene; carbon-14; Byrd; ice core
• Online Access: http://hdl.handle.net/1811/80465

The North Lake Lobe of the Quelccaya Ice Cap in southern Peru represents a wholly unique location for reconstructing paleoclimate conditions. At this location, plant samples were preserved in-situ beneath the advancing glacial ice, and since 2004 have been collected as the ice retreats. The ages of the collected samples were obtained through radiocarbon dating methods. Samples were collected at the surface and at depth. The fine-grained nature of the matrix surrounding the preserved buried samples indicates that several flood events occurred at these sites between ~6,630 cal yr BP and ~6450 cal yr BP due to the ice damming of a lake above the sites. The temporal relationships of the samples were analyzed using a density kernel derivative function, and several groups of significantly related surface samples were determined. We were then able to map several successive advancing ice margins from ~6431 cal yr BP to ~4565 cal yr BP using the temporospatial data of the different sample groups. Comparing the findings of the advancing ice margins to regional climatic records, we determined that the principal driver of the Quelccaya Ice Cap behavior is temperature change, rather than changes in precipitation. Therefore, the advancement seen at the North Lake Lobe of the Quelccaya Ice Cap is another indicator of cooling regional temperatures in South America during the mid-Holocene. When compared to extensive temperature records from locations around the world, the North Lake Lobe advancement supports the hypothesis that a global cooling event occurred during the mid-Holocene. National Science Foundation RAPID Grant Award #1603377 National Science Foundation Paleoclimate Program Award ATM-0318430 Ohio State University Climate, Water, and Carbon Program Ohio State University Office of Research Ohio State College of Arts and Sciences Byrd Polar and Climate Research Center Ice Core Paleoclimate Research Endowment No embargo Academic Major: Earth Sciences