INTEGRATION OF REMOTE SENSING DATA WITH GIS AND GEOCHEMISTRY IN EXPLORATION FOR HYDROCARBON SURFACE EXPRESSIONS, WIND RIVER BASIN, WYOMING

Landsat thematic mapper (TM) images enhanced through linear stretching, low-pass filtering, and color combinations allowed the detection of structural features and a tonal anomaly possibly associated with geochemical alteration of soils and sediments due to hydrocarbon seepage in the Wind River basin, Fremont County, Wyoming. The anomalous feature is also represented by an abnormal reflectance high above sandstone in the 2.08-2.35µm spectral region. Lineament analysis suggests that at least two episodes of tectonic activity affected the area in the past. Concentrations of iron, revealed through spectral band rationing, correspond roughly to the belts of the Chugwater Formation exposed at the Red Canyon Rim and the center of both the Dallas and Derby anticlines. Clay-rich zones occupy lower elevations. A supervised classification image map produced for the area proved correlatable with the available geologic map. X-ray diffraction analysis of sampled soils suggests an association of mixed-layer illite-smectite depleting into kaolinite in the observed anomalous zones. A consistent oxidation halo flanking one of the anomalous zones revealed by the enzyme leach analysis underscores the presence of a reduced body in the subsurface within the area. The conversion of normally illitic-smectite clays to kaolinite and the distinctive oxidation halo are in line with models proposed for the detection of hydrocarbon-induced surface anomalies. Overlay of a digital raster graphics (DRG) map of the area with an enhanced TM image of the scene shows that known oil wells are close to the anomalous zones. The x-ray diffraction and enzyme leach results, however, could not account for the conspicuous concentration of ferric irons in the soil samples. This investigation did show potential prospect zones, which incidentally, are producing oil fields in the area. The study indicates the effectiveness of integrating remote sensing techniques with other essential disciplines of geology for mineral and oil exploration.