GROUND-PENETRATING RADAR USED TO ASSESS AGGREGATE IN CATASTROPHIC FLOOD DEPOSITS, NORTHEAST ALBERTA, CANADA

Coarse-grained aggregate deposited by a catastrophic flood located nor th of Fort McMurray, Alberta, was examined using ground-penetrating ra dar (GPR) and lithostratigraphic logging techniques. GPR transects wer e acquired from an upper scoured zone of flood deposits. Sedimentary s tructures (cross-beds and plane-beds) within the coarse sand and grave l and determinations of depth to bedrock (sediment thickness of the ag gregate) were recognized in the GPR profiles by their varying dielectr ic properties. Fine-grained, conductive underlying oil-sand, till, or glaciolacustrine sediment (silt and clay) attenuated the radar signal. The sedimentary structures mapped from the GPR transects were confirm ed in adjacent trench exposures. We suggest that GPR is an efficient m ethodology for determining volumes of aggregate reserves, thicknesses of aggregate deposits, and mapping sedimentary structures of high-ener gy fluvial sediments.