Skip to main content
U.S. flag

An official website of the United States government

Eric D Anderson

Eric Anderson is a Research Geophysicist with the Geology, Geophysics, and Geochemistry Science Center.

Science and Products

link
Red Mountain CO

A Shallow to Deep View Inside the Hydrothermally Altered and Mineralized Silverton Caldera Complex: New Geologic Insights Gained From Modern Geophysical Interpretations

The Silverton caldera complex in southwest Colorado hosts base and precious metals that have been mined since the late 1800s. Extensive mine workings, excellent bedrock exposures, and deeply incised drainages make this area a natural laboratory ideally suited for furthering our understanding of the mineral systems in a volcanic environment. In addition, state-of-the-art geophysical data processing...
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

A Shallow to Deep View Inside the Hydrothermally Altered and Mineralized Silverton Caldera Complex: New Geologic Insights Gained From Modern Geophysical Interpretations

The Silverton caldera complex in southwest Colorado hosts base and precious metals that have been mined since the late 1800s. Extensive mine workings, excellent bedrock exposures, and deeply incised drainages make this area a natural laboratory ideally suited for furthering our understanding of the mineral systems in a volcanic environment. In addition, state-of-the-art geophysical data processing...
Learn More
link
geophysical survey index map

National Geophysical Data Retrieval and Integration Project

This project helped to streamline the workflow from geophysical data acquisition to data distribution, and additionally provided user support for integration and interpretation of these complex data sets. There were four main objectives: 1) contracting geophysical surveys, 2) converting data from analog to digital format, 3) archiving, retrieving, and integrating geophysical data, and 4) outreach.
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center
link

National Geophysical Data Retrieval and Integration Project

This project helped to streamline the workflow from geophysical data acquisition to data distribution, and additionally provided user support for integration and interpretation of these complex data sets. There were four main objectives: 1) contracting geophysical surveys, 2) converting data from analog to digital format, 3) archiving, retrieving, and integrating geophysical data, and 4) outreach.
Learn More
Filter Total Items: 13

Airborne electromagnetic and magnetic survey data, Silverton, Colorado, 2019

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
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Gravity data in the Wet Mountains area, southcentral Colorado, 2021 to 2022

The U.S. Geological Survey (USGS) collected gravity data in the Wet Mountains, CO from September 2021 to July 2022 to compliment newly collected airborne magnetic data for surface and subsurface geologic mapping. A total of 261 measurements were collected across two Ediacaran-Ordovician alkaline complexes (Gem Park and McClure Mountain) and gabbroic outcrops suspected Ediacaran-Ordovician in age.
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Magnetic susceptibility measurements in the Wet Mountains, Colorado, 2021 to 2022

The U.S. Geological Survey (USGS) collected rock magnetic susceptibility measurements to understand the causative sources of airborne magnetic survey anomalies in the Wet Mountains, Colorado. A total of 808 measurements were collected over 50 locations from August 2021 to June 2022 on rocks ranging from Paleoproterozoic to Oligocene age. These measurements aid the interpretation of newly collected
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Magnetic susceptibility measurements on hydrothermally altered rocks in the Silverton caldera, southwest Colorado

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
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Airborne Geophysical Survey Inventory of the Conterminous United States, Alaska, Hawaii, and Puerto Rico (ver. 3.0, November 2021)

This data release is a compilation of the locations of airborne geophysical surveys in the United States. The inventory documents public airborne geophysical surveys primarily flown by or contracted by the USGS from 1943 to present. In addition, surveys from the State of Alaska, Department of Natural Resources, Division of Geological and Geophysical Surveys (DGGS): Airborne GeophysWeb, the Bureau
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

A snapshot of stakeholder science needs related to drought in the Colorado River Basin

Stakeholder science needs were determined by reviewing more than 200 recently published literature items and web pages from Colorado River Basin (CRB) stakeholders. These stakeholder communications were used to characterize over 400 stakeholder science needs by reviewing their priorities, strategies, issues, missions, and concerns related to drought in the CRB. Members of the CRB Integrated Scienc
By
Arizona Water Science Center, California Water Science Center, Colorado Water Science Center, Fort Collins Science Center, Geology, Geophysics, and Geochemistry Science Center, Nevada Water Science Center, New Mexico Water Science Center, Southwest Biological Science Center, Utah Water Science Center, Wyoming-Montana Water Science Center

Data and results for GIS-based identification of areas that have resource potential for lode gold deposits in Alaska

This data release contains the analytical results and evaluated source data files of geospatial analyses for identifying areas in Alaska that may be prospective for different types of lode gold deposits, including orogenic, reduced-intrusion-related, epithermal, and gold-bearing porphyry. The spatial analysis is based on queries of statewide source datasets of aeromagnetic surveys, Alaska Geochemi
By
Alaska Science Center

Principal facts of regional gravity data in the central Upper Peninsula, Michigan, and northeastern Wisconsin

Gravity data were collected from 2016 through 2019 to assist in mapping surface and subsurface geology in the central Upper Peninsula of Michigan and in neighboring northeastern Wisconsin. This data release provides principal facts for 1536 new gravity stations that were acquired to supplement existing public gravity data coverage.
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Airborne electromagnetic and magnetic survey data of the San Juan-Silverton Caldera complex, Silverton, Colorado, 2019

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 sur
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Density and magnetic susceptibility measurements on Precambrian rocks in the Iron Mountain-Menominee region, Michigan-Wisconsin

The U.S. Geological Survey (USGS) collected rock physical property measurements to help understand causative sources of gravity and magnetic survey anomalies in the Iron Mountain-Menominee region, Michigan-Wisconsin. A total of 2,356 measurements of magnetic susceptibility and density from 152 locations have been conducted on Precambrian rocks. The measurements aid in interpretation of newly acqui
By
Geology, Geophysics, and Geochemistry Science Center

Updated aeromagnetic and gravity anomaly compilations and elevation-bathymetry models over Lake Superior

New gravity and magnetic compilations and elevation-bathymetry models have been compiled for the Lake Superior region. These data provide continuous sets of observations for geologic interpretations spanning political boundaries such as US States and the US-Canada border where bedrock geology is largely concealed beneath glacial deposits and surface water. These data are providing constraints for
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Locatable Mineral Assessment Tracts for the U.S. Geological Survey Sagebrush Mineral Resource Assessment Project

The polygon (vector) feature class represents locatable mineral resource assessment tracts (tracts of land) associated with the Department of the Interior (DOI) Sagebrush Focal Areas in Montana, Wyoming and Utah, central Idaho, and the Oregon-Nevada-Idaho border area. The mineral resources tracts are geographic areas that were assessed by the U.S. Geological Survey (USGS) and were determined to be
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Geologic map of Big Bend National Park, Texas

The purpose of this map is to provide the National Park Service and the public with an updated digital geologic map of Big Bend National Park (BBNP). The geologic map report of Maxwell and others (1967) provides a fully comprehensive account of the important volcanic, structural, geomorphological, and paleontological features that define BBNP. However, the map is on a geographically distorted plan
By
Geology, Minerals, Energy, and Geophysics Science Center, Geosciences and Environmental Change Science Center

Precambrian basement structure map of the continental United States - An interpretation of geologic and aeromagnetic data

The Precambrian basement rocks of the continental United States are largely covered by younger sedimentary and volcanic rocks, and the availability of updated aeromagnetic data (NAMAG, 2002) provides a means to infer major regional basement structures and tie together the scattered, but locally abundant, geologic information. Precambrian basement structures in the continental United States have
By
Geology, Geophysics, and Geochemistry Science Center
Filter Total Items: 49

Colorado River Basin Actionable and Strategic Integrated Science and Technology Project—Science strategy

The U.S. Geological Survey (USGS) conducts a wide variety of science that improves understanding of droughts and their effects on ecosystems and society. This work includes data collection and monitoring of aquatic and terrestrial systems; assessment and analysis of patterns, trends, drivers, and impacts of drought; development and application of predictive models; and delivery of information and
By
Geosciences and Environmental Change Science Center

U.S. Geological Survey Colorado River Basin Actionable and Strategic Integrated Science and Technology (ASIST)—Information Management Technology Plan

IntroductionMore than 840 publications, 575 data releases, and 330 project web pages from the U.S. Geological Survey (USGS) pertain to the Colorado River Basin. Limited interconnections between Colorado River Basin publications, data, and web pages restrict the ability to synthesize and interpret scientific resources. Currently, these pieces are spread across multiple isolated locations, internal
By
Ecosystems, Water Resources, Fort Collins Science Center, Oregon Water Science Center

Geophysical data provide three dimensional insights into porphyry copper systems in the Silverton caldera, Colorado, USA

The Silverton caldera in southwest Colorado, USA hosts polymetallic veins and pervasively altered rocks indicative of porphyry copper systems. Nearly a kilometer of erosion has exposed multiple levels of the hydrothermal systems from shallow lithocaps down to quartz-sericite-pyrite veins. New airborne electromagnetic and magnetic survey data are integrated with previous alteration mapping and porp
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

GIS-based identification of areas that have resource potential for lode gold in Alaska

Several comprehensive, data-driven geographic information system (GIS) analyses were conducted to assess prospectivity for lode gold in Alaska. These analyses use available geospatial datasets of lithologic, geochemical, mineral occurrence, and geophysical data to build models for recognizing different types of gold deposits within physiographic units defined by stream drainage basins that are app
By
Ecosystems, Energy and Minerals, Mineral Resources Program, Alaska Science Center, Geology, Geophysics, and Geochemistry Science Center

Analytical validation of two RT-qPCR tests and detection of spring viremia of carp virus (SVCV) in persistently infected koi Cyprinus carpio

Spring viremia of carp virus (SVCV) ia a carp sprivivirus and a member of the genus Sprivivirus within the family Rhabdoviridae. The virus is the etiological agent of spring viremia of carp, a disease of cyprinid species including koi Cyprinus carpio L. and notifiable to the World Organisation for Animal Health. The goal of this study was to explore hypotheses regarding inter-genogroup (Ia to Id)
By
Ecosystems, Fisheries Program (unpublished), Biological Threats and Invasive Species Research Program, Species Management Research Program, Western Fisheries Research Center, Fish Health Program (FHP)

Alkalic-type epithermal gold deposit model; Chapter R in Mineral deposit models for resource assessment

This report summarizes the primary characteristics of alkalic-type epithermal gold (Au) deposits and provides an updated descriptive model. These deposits, primarily of Mesozoic to Neogene age, are among the largest epithermal gold deposits in the world. Considered a subset of low-sulfidation epithermal deposits, they are spatially and genetically linked to small stocks or clusters of intrusions c
By
Geology, Geophysics, and Geochemistry Science Center

Integrated geophysical analysis provides an alternate interpretation of the northern margin of the North American Midcontinent Rift System, Central Lake Superior

The Midcontinent Rift System (MRS) is a 1.1 Ga sequence of voluminous basaltic eruptions and multiple intrusions followed by widespread sedimentation that extends across the Midcontinent and northern Great Lakes region of North America. Previous workers have commonly used seismic-reflection data (Great Lakes International Multidisciplinary Program on Crustal Evolution [GLIMPCE] line A) to demonstr
By
Ecosystems, Geology, Geophysics, and Geochemistry Science Center, Northern Rocky Mountain Science Center

Ore deposits: Origin, exploration, and exploitation

No abstract available.
By
Geology, Geophysics, and Geochemistry Science Center

Geological and geophysical data for a three-dimensional view—Inside the San Juan and Silverton Calderas, Southern Rocky Mountains Volcanic Field, Silverton, Colorado

IntroductionThe San Juan-Silverton caldera complex located near Silverton, Colorado, in the Southern Rocky Mountains volcanic field is an ideal natural laboratory for furthering the understanding of shallow-to-deep volcanic-related mineral systems. Recent advances in geophysical data processing and three-dimensional (3D) model construction will help to characterize shallow properties important for
By
Mineral Resources Program, Geology, Geophysics, and Geochemistry Science Center

Descriptive models for epithermal gold-silver deposits

Epithermal gold-silver deposits are vein, stockwork, disseminated, and replacement deposits that are mined primarily for their gold and silver contents; some deposits also contain substantial resources of lead, zinc, copper, and (or) mercury. These deposits form in the uppermost parts of the crust, at depths less than about 1,500 meters below the water table, and at temperatures below about 300 °C
By
Ecosystems, Energy Resources Program, Fisheries Program (unpublished), Mineral Resources Program, National Laboratories Program, Science and Decisions Center, Geology, Geophysics, and Geochemistry Science Center, Geology, Minerals, Energy, and Geophysics Science Center, Western Fisheries Research Center, Central Energy Resources Science Center

Quartz-pebble-conglomerate gold deposits: Chapter P in Mineral deposit models for resource assessment

Quartz-pebble-conglomerate gold deposits represent the largest repository of gold on Earth, largely due to the deposits of the Witwatersrand Basin, which account for nearly 40 percent of the total gold produced throughout Earth’s history. This deposit type has had a controversial history in regards to genetic models. However, most researchers conclude that they are paleoplacer deposits that have b
By
Geology, Geophysics, and Geochemistry Science Center

Mineral potential mapping in an accreted island-arc setting using aeromagnetic data: An example from southwest Alaska

The distribution of volcanogenic massive sulfide (VMS), porphyry-epithermal, Alaska-type ultramafic-mafic complexes, intrusion-related Au, and granitoid Sn-W ore deposits in southwest Alaska supports current metallogenic models linking the formation of these deposit types to the emplacement of different suites of igneous rocks during the evolution of this convergent plate margin. Regional-scale ae
By
Geology, Minerals, Energy, and Geophysics Science Center, Geology, Geophysics, and Geochemistry Science Center

Science and Products