GEOLOGICAL APPLICATIONS OF WORLDVIEW-3 SWIR SATELLITE IMAGERY FOR MAPPING SEDIMENTARY ROCKS, EAST-CENTRAL UTAH, AND SOUTHERN NEVADA

As satellite remote-sensing capabilities are continually improving in spectral and spatial resolution, it presents new opportunities for geoscience applications in mineralogical and lithological discrimination. Furthermore, fusion of imagery from satellite platforms with high-resolution UAV imagery and LIDAR data allows mapping and analysis of geological features at unprecedented scales. In this study, Worldview-3 (WV3) satellite imagery was selected because it acquires high-resolution (3.7 m) shortwave infrared images (SWIR). The SWIR imagery consists of eight bands covering wavelengths from 1195 nm to 2365 nm. This surpasses the spectral and spatial resolution that is available with traditional LANDSAT and ASTER imagery. The WV3 data was used to interpret and map bedrock geology for two areas in distinct geologic settings: one site on the Colorado Plateau near Green River, UT and another in the Basin and Range, north of Las Vegas, NV. For each of these areas band ratios, RGB composites of band ratios, and principal components analysis (PCA) were used to discriminate rock types consisting of clastics and carbonates.

Near Green River, UT WV3 imagery of the uppermost Cretaceous Cedar Mountain Formation through the lower portions of the Mancos Shale (Tununk Shale Member) provides an excellent contrast in distinguishing nonmarine from marine geologic units. Utilizing SWIR indices for mapping carbonates ([Band6/Band8][Band3/Band8]), pedogenic carbonates within floodplain deposits of the fluvial Cedar Mountain Formation can be easily distinguished from the marine Mancos Shale. Within the Cedar Mountain Formation this carbonate index is also useful in distinguishing channel sandstone from floodplain deposits.

North of Las Vegas, NV, Neogene deposits of the Muddy Creek Formation are a succession of lacustrine limestone and overlying clastics that onlap Paleozoic carbonates. Again, carbonate indices proved essential in contrasting the lacustrine carbonates from sandstone and mudrocks. In addition, mudrocks could be distinguished from sandstone by utilizing band ratios that emphasize Al, Fe, and Mg hydroxides. These two sites have contrasting depositional and tectonic histories and provide a comparison for the capabilities of WV3 for geologic mapping in areas underlain by sedimentary rocks.