District-level mineral survey using airborne hyperspectral data, Los Menucos, Argentina

The Los Menucos District, Rio Negro, Argentina, provides an excellent case history of a complex epithermal gold system mapped and explored using a combination of field mapping and multispectral/hyperspectral remote sensing. The district offers a host of argillic and advanced argillic alteration minerals at the surface, many of which are difficult to identify visually. A strategy utilizing regional targeting with Landsat TM to optimize field mapping followed by district-level survey with hyperspectral imaging (HSI) data demonstrates the value added by high-spectral resolution aircraft data. Standardized analysis methods consisting of spatial and spectral data reduction to a few key endmember spectra provides a consistent way to map spectrally active minerals. Minerals identified in the Los Menucos district using the JPL Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) include hematite, goethite, kaolinite, dickite, alunite, pyrophyllite, muscovite/sericite, montmorillonite, calcite, and zeolites. Hyperspectral maps show good correspondence with the results of field reconnaissance verification and spectral measurements acquired using an ASD field spectrometer. Further analysis of Hyperion (satellite-based) hyperspectral data indicates that similar mapping results can be achieved from satellite altitudes. These examples illustrate the high potential of hyperspectral remote sensing for geologic mapping and mineral exploration. Mailing address: Dr. Fred A. Kruse, Horizon GeoImaging, LLC, P.O. Box 4279, Frisco, Colorado 80443, U.S.A.; e-mail: [email protected]