Near-surface geophysical data from within the Bonita Peak Mining District in Silverton, Colorado, USA are presented. These data were collected in 2019. The data include fiber optic distributed temperature sensing (FO-DTS) and frequency domain electromagnetic induction (FDEM) data collected in and around roughly 1 km reaches of Cement Creek and California Gulch. Additional data, including ground penetrating radar (GPR) and self potential (SP), were gathered from a peatland that intercepts acid mine drainage from Mogul Mine into Cement Creek. The peatland is located off the eastern bank of Cement Creek in the northern portion of the reach surveyed with FO-DTS and FDEM. In 2021, an FO-DTS, FDEM, and magnetometer (MAG) dataset were collected along both banks of an approximate 3-4 km reach of the Animas River, spanning from Arrastra Gulch upstream to USGS gage 09358000.

This child item contains fiber-optic distributed temperature sensing (FO-DTS) data collected along the streambed interface of two streams named Cement Creek and California Gulch Creek, as well as the Animas River, located near Silverton Colorado. The FO-DTS method utilizes the temperature-dependent backscatter of light pulses emitted along armored fiber-optic cables to evaluate temperature at discrete linear sampling locations. For these deployments a Salixa XT-DTS control unit (Salixa Ltd, Hertfordshire, UK) was used, and measurements were made over several day increments at 0.508 m linear resolution along the streambed interface. Specific locations for collected data are located within the data files, and additional details are contained in the ‘readme’ files within each zip data directory.

This child item contains fiber-optic distributed temperature sensing (FO-DTS) data collected along the streambed interface of two streams named Cement Creek and California Gulch Creek, as well as the Animas River, located near Silverton Colorado. The FO-DTS method utilizes the temperature-dependent backscatter of light pulses emitted along armored fiber-optic cables to evaluate temperature at discrete linear sampling locations. For these deployments a Salixa XT-DTS control unit (Salixa Ltd, Hertfordshire, UK) was used, and measurements were made over several day increments at 0.508 m linear resolution along the streambed interface. Specific locations for collected data are located within the data files, and additional details are contained in the ‘readme’ files within each zip data directory.

This child item contains frequency domain electromagnetic induction (FDEM) data collected along and around Cement Creek California Gulch, and the Animas River near Silverton, Colorado in support of other data collected at the site. The FDEM tool generates an EM field and measures eddy currents generated by conductive and/or magnetic materials in the subsurface in response to the applied field. A Geophex GEM-2 instrument with GPS was used with frequencies ranging from 450 Hz to 47970 Hz. Additional details are contained in the ‘readme.txt’ files within each zip data directory.

This child item contains frequency domain electromagnetic induction (FDEM) data collected along and around Cement Creek California Gulch, and the Animas River near Silverton, Colorado in support of other data collected at the site. The FDEM tool generates an EM field and measures eddy currents generated by conductive and/or magnetic materials in the subsurface in response to the applied field. A Geophex GEM-2 instrument with GPS was used with frequencies ranging from 450 Hz to 47970 Hz. Additional details are contained in the ‘readme.txt’ files within each zip data directory.

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 dataset imported from the USGS National MAP 3D Elevation Program (U.S. Geological Survey, 2019). AEM data were inverted to produce models of electrical resistivity along flight paths. References: U.S. Geological Survey, The National Map, 2019, 3DEP products and services: The National Map, 3D Elevation Program Web page, accessed April 2019 at https://nationalmap.gov/3DEP/3dep_prodserv.html First posted September 16, 2020 Revised August 19, 2022, ver.2.0 Changes in version 2.0: 1. Updated contractor package and raw data to remediate an erroneous calculation of transmitter/receiver altitude. 2. Converted dataset to netCDF format. 3. Added inverted resistivity models for the entire dataset.

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 dataset imported from the USGS National MAP 3D Elevation Program (U.S. Geological Survey, 2019). AEM data were inverted to produce models of electrical resistivity along flight paths. References: U.S. Geological Survey, The National Map, 2019, 3DEP products and services: The National Map, 3D Elevation Program Web page, accessed April 2019 at https://nationalmap.gov/3DEP/3dep_prodserv.html First posted September 16, 2020 Revised August 19, 2022, ver.2.0 Changes in version 2.0: 1. Updated contractor package and raw data to remediate an erroneous calculation of transmitter/receiver altitude. 2. Converted dataset to netCDF format. 3. Added inverted resistivity models for the entire dataset.

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 groundwater. Water temperature and specific conductance were measured at a subset of locations. Elevation for each location was subsequently assigned using an existing LIDAR data set. Similar procedures were followed at additional sites such as where surface flows entered Mineral Creek (right (RBI) and left (LBI) bank inflows) and the main stem of Mineral Creek (STR). These data are provided in a visual format through the associated KMZ file (224 MB), which provides an HTML formatted pop-up of unique point data and photograph when a waypoint is selected. This release is complementary to a synoptic study conducted in 1999 (Kimball and others, 2007). References: Kimball, B.A., Walton-Day, K. and Runkel, R.L., 2007, Quantification of metal loading by tracer injection and synoptic sampling, 1996-2000, chap. E9 of Church, S.E., von Guerard, P., and Finger, S.E., eds., Integrated investigations of environmental effects of historical mining in the Animas River Watershed, San Juan County, Colorado: U.S. Geological Survey Professional Paper 1651, p. 417–495. https://doi.org/10.3133/pp1651.

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 groundwater. Water temperature and specific conductance were measured at a subset of locations. Elevation for each location was subsequently assigned using an existing LIDAR data set. Similar procedures were followed at additional sites such as where surface flows entered Mineral Creek (right (RBI) and left (LBI) bank inflows) and the main stem of Mineral Creek (STR). These data are provided in a visual format through the associated KMZ file (224 MB), which provides an HTML formatted pop-up of unique point data and photograph when a waypoint is selected. This release is complementary to a synoptic study conducted in 1999 (Kimball and others, 2007). References: Kimball, B.A., Walton-Day, K. and Runkel, R.L., 2007, Quantification of metal loading by tracer injection and synoptic sampling, 1996-2000, chap. E9 of Church, S.E., von Guerard, P., and Finger, S.E., eds., Integrated investigations of environmental effects of historical mining in the Animas River Watershed, San Juan County, Colorado: U.S. Geological Survey Professional Paper 1651, p. 417–495. https://doi.org/10.3133/pp1651.

This dataset includes magnetotelluric (MT) sounding data collected in July 2019 in the Silverton Caldera complex, Colorado, in the Southern Rocky Mountain Volcanic Field, by the U.S. Geological Survey (USGS). Along with geologic mapping, airborne magnetics, airborne electromagnetics, and audiomagnetotellurics, the USGS collected MT data at 24 sites along five profiles ranging from 2 to 5 kilometers in length: across Red Mountain of the Silverton caldera, within the caldera in Eureka Graben, across the south-eastern margin of the caldera along Arrastra Gulch, across the southern margin of the caldera along the western margin of Kendall Mountain, and across the south-western margin of the caldera along South Fork Mineral Creek.