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

Abstract

Cover: Three-dimensional perspective view of the Lake City caldera in the San Juan Mountains of Colorado, looking toward the northwest. A map showing surficial occurrence of clay, sulfate, mica, carbonate, and other minerals derived from spectroscopic analysis of ASTER data provided in this publication is draped over a USGS digital elevation model. Background image is derived from National Agriculture Imagery Program aerial photography. Lake San Cristobal along the Lake Fork of the Gunnison River is visible at right. Advanced argillic alteration (shown in yellow, red, and orange colors) is clearly visible on Red Mountain above the lake and within the Silverton caldera in the distance at upper left.

Automated mapping of mineral groups and green vegetation from Landsat Thematic Mapper imagery with an example from the San Juan Mountains, Colorado

“…These rocks and waste materials contain minerals that can be identified using spectral analysis of satellite remote sensing data. Analysis of multispectral data acquired by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER, http://asterweb.jpl.nasa.gov/) sensor carried by the National Aeronautics and Space Administration (NASA) Earth Observing System Terra satellite is currently being employed to generate mineral group maps over large areas of the United States (U.S.) and its territories in support of USGS assessment efforts (Rockwell, 2012).…”

Identification of Multi-Style Hydrothermal Alteration Using Integrated Compositional and Topographic Remote Sensing Datasets

“…Band Ratios (Table 3), [18][19][20]25] and spectral matching [26] analyses were applied to the SWIR and TIR datasets. The ASTER satellite has 14 spectral bands offering many permutations of Band Ratios [18][19][20]25], and spectral matching [26] analyses were applied to the SWIR and TIR datasets.…”

“…The ASTER satellite has 14 spectral bands offering many permutations of Band Ratios [18][19][20]25], and spectral matching [26] analyses were applied to the SWIR and TIR datasets. Table 3.…”

“…Many common rock-forming minerals such as quartz, feldspars, olivines, pyroxenes, micas, and clay minerals have spectral features in the 8-14 µm wavelength region ( Figure 7A) [9,11,14,19,21,30,31]. The emissivity minima features of quartz are related to fundamental asymmetric Si-O stretching vibrations (reststrahlen bands) characterised by emission minima near 8.40 and 8.95 µm, separated by a sharp emission maximum at 8.63 µm.…”

“…and alteration minerals that display absorption features associated with Mg-OH and Al-OH bonds [8][9][10][11][12][13][14][15][16][17][18][19][20]. Although these reflectance-based datasets have been successful, there are significant limitations in the range and quality of the geological parameters that can be retrieved, as many important rock-forming minerals (e.g., silicates) do not display diagnostic absorption features at VNIR/SWIR wavelengths [9,20,21].…”