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Hydrologic reconnaissance of Mineral Creek near Silverton, Colo., was conducted from June 25-27, 2020. Both banks of Mineral Creek and the adjacent hillsides were walked, starting near the ghost town of Chattanooga and proceeding downstream to the confluence of Mineral Creek with the Middle Fork of Mineral Creek. The purpose of this reconnaissance was to identify areas of emergent groundwater on the right (EGR) and left (EGL) banks, a task that was accomplished by following observed surface flows (seeps and springs) upgradient to the point at which they emanated from the subsurface. Coordinates, using a handheld global positioning system (GPS) device, and photographs were obtained at these locations of emergent...
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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, Colorado and the Four Corners Region of the United States (Rockwell and others, 2021). Spectral index (e.g. 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 results may indicate the presence of near-surface pyrite, which can be a potential non-point source of acid rock drainage....
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The U.S. Geological Survey (USGS) collected magnetic susceptibility measurements on rock outcrops to help understand causative sources of magnetic survey anomalies in the Silverton caldera region, southwest Colorado. A total of 1,400 measurements of magnetic susceptibility from 87 locations have been conducted on Paleogene volcanic and plutonic rocks that have been hydrothermally altered. Magnetic susceptibility measurements were taken using an SM30 handheld instrument manufactured by ZH Instruments. The measurements aid in understanding the geology and potential mineral resources in the Silverton caldera. Previously mapped lithologies and alteration assemblages were used to guide measurement locations. Multiple...
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Airborne electromagnetic (AEM) and magnetic survey data were collected during April and May 2019 along 1,467 line-kilometers in the San Juan-Silverton Caldera complex, Colorado, in the Southern Rocky Mountain Volcanic Field. Data were acquired by Geotech, Ltd. with the versatile time-domain electromagnetic (VTEM-ET) system together with a Geometrics optically pumped cesium vapor magnetometer. The survey was flown at a mean flight height of 140 meters (m) above terrain in various line directions and line spacings ranging from 150 m to 600 m. Multiple variable-spaced lines were flown along rivers and streams in the survey area. USGS provided the contractor with the San Juan National Forest Lidar Point Cloud elevation...
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Note: this data release has been deprecated. Please see new data release here: https://doi.org/10.5066/P92IADBP. Airborne electromagnetic (AEM) and magnetic survey data were collected during April and May 2019 along 1,467 line-kilometers in the San Juan-Silverton Caldera complex, Colorado, in the Southern Rocky Mountain Volcanic Field. Data were acquired by Geotech, Ltd. with the versatile time-domain electromagnetic (VTEM) system together with a Geometrics optically pumped cesium vapor magnetometer. The survey was flown at a mean flight height of 140 meters (m) above terrain in various line directions and line spacings ranging from 150 m to 600 m. Multiple variable-spaced lines were flown along rivers and streams...


    map background search result map search result map 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 Airborne electromagnetic and magnetic survey data of the San Juan-Silverton Caldera complex, Silverton, Colorado, 2019 Hydrologic reconnaissance to identify areas of emergent groundwater, Mineral Creek, near Silverton, Colorado, June 2020 Airborne electromagnetic and magnetic survey data, Silverton, Colorado, 2019 Magnetic susceptibility measurements on hydrothermally altered rocks in the Silverton caldera, southwest Colorado Magnetic susceptibility measurements on hydrothermally altered rocks in the Silverton caldera, southwest Colorado Airborne electromagnetic and magnetic survey data of the San Juan-Silverton Caldera complex, Silverton, Colorado, 2019 Airborne electromagnetic and magnetic survey data, Silverton, Colorado, 2019 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