Title: Improved Automated Identification and Mapping of Iron Sulfate Minerals, Other Mineral Groups, and Vegetation using Landsat 8 Operational Land Imager Data, San Juan Mountains, Colorado, and Four Corners Region By Barnaby W. Rockwell, William R. Gnesda, and Albert H. Hofstra 2021 U.S. Geological Survey Scientific Investigations Map 3466 Data release available at https://doi.org/10.5066/P9ONOKKX ABSTRACT: Multispectral remote sensing data acquired by the Landsat 8 Operational Land Imager (OLI) sensor were analyzed using a new, automated technique to generate a map of exposed mineral and vegetation groups in the western San Juan Mountains, Colo. and the Four Corners Region of the United States. Band ratio results were combined into displayed mineral and vegetation groups using Boolean algebra. New analysis logic has been implemented to exploit the coastal aerosol band in Landsat 8 OLI data and identify concentrations of iron sulfate minerals. These may indicate the presence of near-surface pyrite, which can be a potential non-point source of acid rock drainage. Zoned occurrences of iron sulfate minerals in areas surrounding and down gradient of known sources of pyrite have been mapped using this technique. They show high correlation with occurrences of jarosite-bearing mineral assemblages, as mapped using airborne imaging spectrometer data and supporting field verification surveys. Mapping the occurrence of iron sulfate minerals produced by the weathering and oxidation of pyrite in exposed hydrothermally altered rocks can also provide an important indicator of the genetic environment of alteration and the associated mineral deposit type. The automated analysis methodology is being employed to rapidly and cost-effectively generate maps of large regions of the United States in support of U.S. Geological Survey mineral resource and mineral-environmental assessments. This map, which includes the ERDAS IMAGINE thematic raster format in the data release, has been attributed by pixel value with mineral and vegetation group classification data, which can be queried in most image processing and GIS software packages. DISCLAIMERS: 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 USGS or the U.S. Government 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 may contain copyrighted material as noted in the text. Permission to reproduce copyrighted items for other than personal use must be secured from the copyright owner. ---------------------------------------------------------------------------- FILES: The map sheet and pamphlet can be downloaded via the Web from the U.S. Geological Survey publications website at https://doi.org/10.3133/sim3466. The map sheet is an Adobe Portable Document Format (PDF) (sim3466_sheet1.pdf) from which paper copies may be printed. Bookmarks for ten map layouts are organized based on selections from the preserved layers. This combination of layers may be adjusted based on the reader’s preferences. These bookmarks can also be activated with the radio buttons that appear on the map sheet as the last element in the Explanation. MAP LAYOUTS: Satellite Footprints Geologic Map ASTER—Mineralogy+vegetation Landsat 7—Mineralogy+vegetation Landsat 8 OLI—Mineralogy+vegetation Landsat 8 OLI—Bands 431 Landsat 8 OLI—Bands 541 Landsat 8 OLI—Bands 651 Landsat 8 OLI—Bands 671 Base Maps REPORT FILES: 00ReadMe.txt sim3466_pamphlet.pdf sim3466_sheet1.pdf ---------------------------------------------------------------------------- The GIS database for this report is located at and can be downloaded via the Web from ScienceBase at https://doi.org/10.5066/P9ONOKKX HOW TO OBTAIN THE DIGITAL MAP AND PAMPHLET FILES: The map sheet and pamphlet can be obtained via the Internet from the U.S. Geological Survey publications website. Go to the web page at https://doi.org/10.3133/sim3466/ and follow the directions to download the files. The main product is a Portable Document Format (PDF) map, which requires Adobe Acrobat for viewing. This Portable Document Format (PDF) file (sim3466_sheet1.pdf) can be downloaded, from which paper copies may be printed. Acrobat software runs on a variety of systems, and is available for download free of charge from Adobe at http://www.adobe.com. PUBLICATION REFERENCE: Rockwell, B.W., Gnesda, W.R., and Hofstra, A.H., 2021, Improved automated identification and mapping of iron sulfate minerals, other mineral groups, and vegetation from Landsat 8 Operational Land Imager Data, San Juan Mountains, Colorado, and Four Corners Region: U.S. Geological Survey Scientific Investigations Map 3466, 1 sheet, scale 1:325,000, 37-p. pamphlet, https://doi.org/10.3133/sim3466. HOW TO OBTAIN THE DIGITAL GIS FILES: The digital GIS files constituting the geologic map database of this report can be obtained from the U.S. Geological Survey via the Internet from ScienceBase: ScienceBase link: https://doi.org/10.5066/P9ONOKKX DATA RELEASE REFERENCE: Rockwell, B.W., Gnesda, W.R., 2021, Digital map of iron sulfate minerals, other mineral groups, and vegetation of the San Juan Mountains, Colorado, and Four Corners Region derived from automated analysis of Landsat 8 satellite data: U.S. Geological Survey data release, https://doi.org/10.5066/P9ONOKKX. ArcReader may be downloaded free of charge from http://www.esri.com/software/arcgis/arcreader/download for viewing additional files included in this report. This map is offered as an online-only, digital publication. Users should be aware that, because of differences in rendering processes and pixel resolution, some slight distortion of scale may occur when viewing it on a computer screen or when printing it on an electronic plotter, even when it is viewed or printed at its intended publication scale.