OBSERVING THE PALEOGEOMORPHOLOGY OF WALKER LAKE CINDER CONE, AZ, USING GROUND PENETRATING RADAR

GPR has been used to identify and investigate subsurface topography in many geologic environments. In this study, it has been useful in understanding the paleogeomorphology of Walker Lake, a basaltic cinder cone located within the San Francisco volcanic field in northern Arizona. The cone consists of Miocene to Holocene volcanic rock, overlaid by a tephra deposit estimated to be from a 15,440 year old eruption from Saddle Mountain, located 5 km north of Walker Lake. GPR data were collected down and along the western slope of the Walker Lake cinder cone using a GSSI system with a 200 MHz antenna in order to detect stratigraphy associated with the Walker Lake and Saddle Mountain deposits. Data reveal subsurface cone and tephra deposits to depths of at least 20 meters allowing for analysis of erosional and depositional boundaries within the two deposits. In addition to mapping the Saddle Mountain deposit thickness along the slope, downslope and along-slope GPR transects show structures interpreted as paleo gullies at the Walker Lake/Saddle Mountain contact. By using GPR to investigate the subsurface stratigraphy at Walker Lake cinder cone, we are better able to compare current erosional features with structures observed along the original scoria deposits of the cinder cone.