ORIGIN AND TRANSPORT OF ROCK GLACIER ICE IN TAYLOR VALLEY, ANTARCTICA BY ANALYSIS OF ICE CRYSTAL FABRIC

Taylor Valley, located in the McMurdo Dry Valleys of Antarctica, is home to a number of rock glaciers. These geomorphological features consist of a mixture of slow-moving ice and sediment, most often sourced from nearby glaciers. Information about the origin and transport of these rock glaciers can be studied through observation of ice crystal fabric and orientation. About 10% of the valley walls are covered by rock glaciers in central Taylor Valley, occurring at elevations between 300 and 800 m above sea level. Ice cores from Taylor Valley rock glaciers were used to understand the variations in ice crystal habits down core to better understand the flow history for each rock glacier. Vertical and horizontal ice thin sections were cut and photographed in a cold lab at the National Ice Core Laboratory. Thin sections were analyzed for grain c-axes and compiled into Schmidt plots at Pennsylvania State University. Digital analysis of grain boundaries and bubbles were evaluated using Photoshop and the QIA-64 add-on from Reindeer Graphics. Results from Sollas rock glacier, located in Taylor Valley, indicate a shift from meltwater recrystallization to ice flow down core at shallow depths. This observation corresponds to stable isotope data from the same ice core. Understanding of the general geomorphic stability and flow history of rock glaciers is important given potential future warming, the impacts of which could be observed and monitored through these landforms. Future work still needs to be done to increase understanding of the behavior of ice crystal fabric as it pertains to rock glaciers to better distinguish between ice flow and meltwater recrystallization.