Mapping the floor of Lake Powell: Preliminary discussion of CHIRP data along the San Juan Sediment Delta

Lake Powell began to fill with water and sediment in 1963 and reached full capacity in 1980. Previous studies have documented the presence of trace metals and other contaminants in the sediment deltas of the reservoir. Although very little is known about the volume and distribution of sediment and contaminants. This study uses seismic reflection profiles to inform core site selection for a larger project that aims to determine the extent of heavy metal contamination in Lake Powell. I divided the San Juan delta of Lake Powell into six distinct sections based upon interpreted sediment thickness from the seismic profiles and from the lake-floor gradient along the delta. Twelve sites for prospective coring were identified through analysis of the CHIRP seismic reflection data which was collected longitudinally along the delta. I identified six locations for coring, in each section of the delta, where sediment is likely representative of the section. The remaining six locations are particularly thick sediment packages within each of the six delta divisions. I also propose four preliminary sediment facies within the delta: rock outcrops, alluvial deposits, post-impoundment sediment deposits, and bedrock. This study provides an initial analysis of the shape and composition of the San Juan sediment delta to inform further study of the deltaic deposits