MORPHOLOGICAL AND TOPOGRAPHIC CHARACTERISTICS OF MCMURDO DRY VALLEYS PALEOLAKE DEPOSITS: USING LIDAR TO ASSESS LGM-AGE HYDROLOGICAL PROCESSES

Located in the McMurdo Dry Valley of Antarctica, Taylor Valley holds remnants of glaciofluvial landforms generated during the Last Glacial Maximum. Glacial melt and the expanded Ross Sea ice sheet formed ice-dammed lakes, which then resulted in the development of multi-leveled deltas. Paleolake levels in the MDV are estimated from relict deltas perched on the valley walls and soluble salt distribution in soils. The elevation of the deltas and radiocarbon age of the algal mat embedded in the deltas indicates age. From these data a paleolake level history has been derived and used to infer hemispheric circulation patterns. Recent geomorphic studies have called into question the results of these findings.

The objective of this project is to use new LiDAR datasets from Taylor Valley and determine how deltas, fluvial terraces, and other glaciofluvial deposits are distributed along the valley walls. We mapped landform size, elevation, slope, and orientation to determine whether relict sandy deposits are low-angle (delta topsets) or high-angle (fluvial terraces). Landforms were then correlated by elevation to evaluate proposed paleolake shorelines in order to assess the size and locations of the paleolakes that were once in Taylor Valley. The radiocarbon dates for each deposit are then correlated with landform position in order to evaluate the duration of different lake stands. Understanding the relationships between the climate change during the Last Glacial Maximum and the melt in Taylor Valley can help us understand the rates of terrestrial ice sheet collapse during interglacial periods and can help evaluate the significant of morphological paleoclimate records from Antarctica.