Integrated Ground-based Hyperspectral Imaging, Terrestrial Laser Scanning, and Geochemical Study of Geological Outcrops



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Ground-based hyperspectral imaging and terrestrial laser scanning are becoming popular in geosciences. This dissertation combined these techniques with traditional geochemical data obtained by X-ray fluorescence, fire assay metallurgy, and inductively coupled plasma mass spectrometry for three case studies. Hyperspectral data showed that the studied outcrop of the Mississippian Boone Formation is mostly limestones with interbedded chert nodules. Fractures extracted from laser scanning and high-resolution photography showed that larger fractures strike dominantly ENE-WSW, chert nodules hold more fractures, and that chert nodule distribution is heterogeneous vertically and horizontally. A virtual outcrop model was assembled as a reservoir analog, and anisotropic vertical fracture permeability was inferred from the dominancy of fracture orientations, the preferential distribution of fractures, and the distribution of chert nodules. Lithologies were identified from semi-quantification of mineralogy on a roadcut of the Eagle Ford Group. No spatial relationship between grainstones and bentonites was found, which disagrees with the nutrient supply hypothesis that iron from volcanic ash controls lithologic cyclicity. On the contrary, intervals between grainstone beds matched astronomic orbital components and supports the Milankovitch cycle hypothesis. Whole-rock geochemistry confirmed hyperspectral mapping, and enrichment of uranium and molybdenum indicated “unrestricted” paleo-hydrogeology and anoxic to euxinic paleo-redox conditions. Aspect ratios of grainstone bodies indicated variations in paleo-hydrogeology and carbonate sediment supply. These data extracted horizontal heterogeneities as a reservoir analog. Hyperspectral imaging scanned a drilled core covering the basal Claron Formation and Callville Limestone in Goldstrike district, Utah, which is similar to Carlin-type deposits in Nevada with sediment-hosted disseminated gold. Variations in mineralogy showed an optimum lithology combination of limestone above and silisiclastic rocks below and alterations including decarbonatization and argillization, which correlate with gold mineralization that can be used for exploration. This dissertation demonstrates the utilization of innovative remote sensing techniques in mapping mineralogy and fractures. Mineralogy is useful for determining rock properties and tracing alteration processes, especially those involved with fluids like hydrocarbons or geothermal fluids, while fracture data are fundamental for optimizing fluid flow in hydrocarbon reservoirs. These remote sensing techniques are powerful tools that are revolutionizing the way we acquire field data.



Ground-based hyperspectral imaging, Terrestrial laser scanning, Geochemistry, Virtual Outcrop Model