DESCRIPTION AND VALIDATION OF AN AUTOMATED METHODOLOGY FOR MAPPING MINERALOGY, VEGETATION, AND HYDROTHERMAL ALTERATION TYPE FROM ASTER SATELLITE IMAGERY WITH EXAMPLES FROM THE SAN JUAN MOUNTAINS, COLORADO By Barnaby W. Rockwell First posted January 25, 2012 U.S. Geological Survey Scientific Investigations Map 3190 REVISED February 2013 (map sheets only) See the REVISION HISTORY FILE for details. ABSTRACT The efficacy of airborne spectroscopic, or “hyperspectral,” remote sensing for geoenvironmental watershed evaluations and deposit-scale mapping of exposed mineral deposits has been demonstrated. However, the acquisition, processing, and analysis of such airborne data at regional and national scales can be time and cost prohibitive. The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) sensor carried by the NASA Earth Observing System Terra satellite was designed for mineral mapping and the acquired data can be efficiently used to generate uniform mineral maps over very large areas. Multispectral remote sensing data acquired by the ASTER sensor were analyzed to identify and map minerals, mineral groups, hydrothermal alteration types, and vegetation groups in the western San Juan Mountains, Colorado, including the Silverton and Lake City calderas. This mapping was performed in support of multidisciplinary studies involving the predictive modeling of surface water geochemistry at watershed and regional scales. Detailed maps of minerals, vegetation groups, and water were produced from an ASTER scene using spectroscopic, expert system-based analysis techniques which have been previously described. New methodologies are presented for the modeling of hydrothermal alteration type based on the Boolean combination of the detailed mineral maps, and for the entirely automated mapping of alteration types, mineral groups, and green vegetation. Results of these methodologies are compared with the more detailed maps and with previously published mineral mapping results derived from analysis of high-resolution spectroscopic data acquired by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) sensor. Such comparisons are also presented for other mineralized and (or) altered areas including the Goldfield and Cuprite mining districts, Nevada and the central Marysvale volcanic field, Wah Wah Mountains, and San Francisco Mountains, Utah. The automated mineral group mapping products described in this study are ideal for application to mineral resource and mineral-environmental assessments at regional and national scales. DISCLAIMERS This database, identified as SIM 3190, has been approved for release and publication by the Director of the USGS. Although this database has been subjected to rigorous review and is substantially complete, the USGS reserves the right to revise the data pursuant to further analysis and review.Furthermore, it is released on condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use. Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty, expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution constitute such warranty. The U.S.Geological Survey shall not be held liable for improper or incorrect use of the data described and/or contained herein. Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey. Although this information product, for the most part, is in the public domain, it also contains copyrighted material as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner. Note: Although the Federal Geographic Data Committee-compliant metadata files are intended to document the data set in nonproprietary form, as well as in ArcGIS and ERDAS Imagine formats, these metadata files may include some terminology specific to those software packages. DATA FILES List of files: 00ReadMe.txt SIM3190_pam.pdf SIM3190_sheet1_RGB_rev.pdf SIM3190_sheet2_RGB_rev.pdf SIM3190_sheet3_RGB_rev.pdf SIM3190_sheet4_RGB_rev.pdf SIM3190_sheet5_RGB_rev.pdf SIM3190_highres_figures Fig1_fe-mg-musc_specplot.pdf Fig2_iron_veg_hydsil_specplot3.pdf Fig3_alun-pyroph-kaol_specplot.pdf Fig4_sericite-smect-kaol_specplot2.pdf Fig5_carb-prop-dolomite_specplot.pdf Fig6_ferrous-iron.pdf Fig7_Animas-Rico_MEA_2009-10_av_ast_ferrous_comparison2_10-11 [converted].pdf Fig8_Goldfield_2011_AV-AST-Auto_comparison_600d_10-11_opt.pdf Fig9_Anismas-Rico_MEA_2009-10_av-ast_2um-jarosite_comparison2_10-11 [Converted].pdf Fig10_Animas-Rico_MEA_2009-10_av-ast_argillic_comparison5_alt55_10-11 [Converted].pdf Fig11_Marysvale_ASTER_detailed-autoAlt55_comparison [Converted]_opt.pdf Fig12_Goldfield_2011_AV_AST-AutoMerge_comparison_AutoAlt55 [Converted]_opt.pdf Fig13_Montezuma_2011_AST-AutoMerge_comparisonAutoAlt55 [Converted].pdf Fig14_Cuprite_AVIRIS98_geogrid.pdf Fig15_Cuprite_ASTER_Autoalt_comparison [Converted].pdf Fig16_PineGrove_NG_2010_comparison3_pt_utm_aa55merge [Converted]_opt.pdf Fig17_WahWah-Legend.pdf Metadata files: SIM3190_metadata.zip sanjuans_aster_alteration5_pt-utm.img_metadata.txt sanjuans_aster_autoalt54_pt_utm.img_metadata.txt sanjuans_aster_autoalt55_merge_pt-utm.img_metadata.txt sanjuans_aster_fe-veg-water_pt-utm.img_metadata.txt sanjuans_aster_minvue468_pt-utm.img_metadata.txt sanjuans_aster_swir_pt-utm.img_metadata.txt Datafiles: img files: sanjuans_aster_alteration5_pt-utm.img sanjuans_aster_autoalt54_pt_utm.img sanjuans_aster_autoalt55_merge_pt-utm.img sanjuans_aster_fe-veg-water_pt-utm.img sanjuans_aster_minvue468_pt-utm.img sanjuans_aster_swir_pt-utm.img shapefile: sanjuans_aster_scratch_geodrg_shapefile.zip Note: The pamphlet contains figures that are linked to the original high resolution figures that were provided by the author. HOW TO OBTAIN THE DIGITAL FILES The digital files constituting the geologic map database of this report can be obtained via the Internet from the U.S.Geological Survey publications website. Go to the web page at http://pubs.usgs.gov/sim/3190/ and follow the directions to download the files. The main products are Portable Document Format (.pdf) maps and a manuscript, which require Adobe Acrobat for viewing. Acrobat software runs on a variety of systems, and is available for download free of charge from Adobe at http://www.adobe.com. ArcReader may be downloaded free of charge from http://www.esri.com/software/arcgis/arcreader/download.htm for viewing addtional files included in this report.