GIS Analysis of Marine Geophysical Signatures to Decipher Depositional Patterns of Platinum Placer in Offshore Goodnews Bay Region, Alaska.

The Goodnews Bay region, located in the southwest Alaska, was the only primary platinum-producing region in the U.S. until 1980 with about 20 metric tons of platinum recovered. The U.S Geological Survey has estimated the coastal platinum placer potential at Goodnews Bay region to be 155 metric tons. In order to estimate and locate the offshore platinum placer distribution in this region, a GIS database was developed with the information derived from data collected over more than 50 years by industries and government agencies. These data include comprehensive information on grain mineralogy, modes of offshore placer transport, bathymetry, location of paleo-channels, geology, glacial history, extent of drowned ultramafic rocks, wave-current direction, geophysical surveys and knowledge of paleoshore lines. In this study, we have used geophysical data sets from earlier research and have compared those to the recent data acquisition from our "Platinum Cruise 2005" to Kuskokwim Bay. GIS analysis has been used to decipher the influence of various subsurface marine features as obtained from the geophysical signatures on the depositional pattern of placer platinum in this region.