REFLECTIVE SPECTROSCOPY INVESTIGATION OF ARCHEAN BASEMENT ROCKS FROM TORREY CANYON, WYOMING: IMPLICATIONS FOR FUTURE HIGH RESOLUTION HYPERSPECTRAL MAPPING

Hyperspectral remote sensing is an established technology for investigating geologic materials on earth and other planets. One limitation of this technology is that it can be difficult to distinguish lithologies that are close in composition. There are also challenges for definitively identifying lithologies that are intimately mixed at sub pixel levels in hyperspectral imaging as well. As unmanned air vehicles become more broadly implemented it will be possible to image intimately mixed lithologies at high resolution owing to target distance and overall improvements in data acquisition quality. However, achieving this still requires detailed spectral libraries to be assembled. Archean rocks at Torrey Canyon, Wyoming present an opportunity to high resolution hyperspectral mapping on intimately mixed lithologies. Torrey Canyon lithologies are interesting remote sensing targets also because there is very little detailed reflective spectroscopy and hyperspectral work that has been done on Archean rocks and that which has been done has been highly focused on gold ores. An improved understanding and capability to map Archean rocks has broad implications for resource exploration and environmental management. A variety of lithologies were characterized using an ASD spectroradiometer using a contact probe and polarized light microscopy. Lithologies include amphibolites, mica schists and granitoids with domain t grain sizes that vary from approximately 0.1 to 5.0 mm. Preliminary results suggest that reflective spectroscopy needs to be acquired from many lithologies as variability exists within designated units. However, reflective spectroscopy results indicate that lithologies can be separated primarily on overall brightness and specific hydroxyl related features. Limited work on lichens also suggests potential for mapping at high resolution. High-resolution hyperspectral mapping has potential to be a tool to better understand Archean rocks of the Western US.