Provenance Study of Reedy Glacier and West Antarctic Ice Stream Tills

• Main Author: Kramer, Katie L.
• Other Authors: Licht, Kathy J., Swope, R. Jeffery, Barth, Andrew, 1958-
• Format: Thesis
• Language: English
• Published: 2008
• Subjects: Antarctica; Ice Stream; Till; Reedy Glacier; Geology > Antarctica; Glaciers > Antarctica; Ice streams > Antarctica; Antarctic; East Antarctica; Ross Sea; West Antarctica; Whillans; Antarc*; Ice Sheet
• Online Access: https://hdl.handle.net/1805/1695; https://doi.org/10.7912/C2/510

Indiana University-Purdue University Indianapolis (IUPUI) In January 2007, 26 samples of till from 6 different moraines along the Reedy Glacier, East Antarctica were collected with the goal of differentiating between these samples and till collected from the base of the Whillans, Kamb, and Bindschadler Ice Streams of West Antarctica. The ability to differentiate between East and West Antarctic ice will allow us to constrain ice flow into the central Ross Sea during the Last Glacial Maximum (LGM), which has implications for more accurate reconstructions of the Ross Ice Sheet and its behavior. Moraines sampled from the head of Reedy Glacier give insight to the geology beneath the EAIS, and may be representative of what the glacier is eroding from its bed. Samples along the trunk of the glacier capture representative rock types eroded along the length of Reedy Glacier. At each moraine 3 replicate sub-sites were selected for collection to represent the diversity of material within each moraine. Comparisons are based on the composition of pebbles, particle size distributions, and sand petrography. Analysis of the pebble fraction shows that each sub-site contains similar rock types, however, the concentration of each rock type varies as much as 25-35%. Similar variation is also seen within the sub-site sand fraction. Both the pebble and sand fraction reflect the mapped bedrock geology. The dominant pebble types are coarse-grained felsic and intermediate igneous rocks, as well as quartzite. Similarly felsic igneous grains, quartzite, quartz, and feldspar characterize the sand fraction. Particle size analysis shows that v Reedy Glacier till averages 85% sand. The subglacial West Antarctic samples contain approximately 30% sand, and equal amounts of silt and clay, approximately 35% each. An observation of the sand fraction from beneath the West Antarctic Ice Streams shows composition similar to tills from Reedy Glacier. However, tills from the base of the West Antarctic Ice Streams contain up to 75% polymict grains, ...