AN INVESTIGATION OF MECHANICAL WEATHERING PROCESSES IN THE MCMURDO DRY VALLEYS, ANTARCTICA USING ACOUSTIC EMISSION AND MICROMETEOROLOGICAL MONITORING

The McMurdo Dry Valleys (MDV) region of Antarctica is one of the coldest, driest, and windiest places on the planet, and serves as an extreme endmember for terrestrial surface processes. However, our understanding of the drivers of rock breakdown in this landscape is limited, particularly in inland and high elevation locations where liquid water is rare. In order to characterize better the weathering and erosional processes in the MDV, we need to (1) detect the slow, subcritical growth of cracks, which ultimately leads to rock disaggregation, and (2) relate crack formation and growth to the responsible environmental catalysts. Here, we present preliminary data from an in situ rock breakdown monitoring station deployed in one of the inland-most portions of the MDV, Beacon Valley.

The station consists of an acoustic-emission (AE) monitoring system, which detects elastic waves released during the formation and extension of cracks, thermocouples and surface moisture sensors adhered to rock surfaces, and a meteorological station. We will compare the timing of AE events (cracking) on four dolerite boulders to the associated micrometeorological data to determine what environmental forcings are responsible for rock breakdown in the coldest and driest portions of the MDV.