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Search indexed USGS publications on groundwater, aquifers, geologic maps, mineral resources and earthquakes. Explore source records by subject and place.
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Aeromagnetic map of the Westcliffe-Royal Gorge area, Custer and Fremont Counties, Colorado
No abstract available.
Gravity anomaly map of the United States; Part A: Conterminous United States
No abstract available.
Hydrogeologic framework and properties of regional aquifers in the Hollandale Embayment, southeastern Minnesota
In 1977, the U.S. Geological Survey began a series of investigations of regional aquifer systems in the United States. These studies will provide quantitative information for use in developing and managing regional ground-water supplies. One of these studies, the Northern Midwest Regional Aquifer-System Analysis (RASA) project, concerns the Cambrian and Ordovician age aquifers that occur in southeastern Minnesota and in parts of five other states: Illinois, Indiana, Iowa, Missouri, and Wisconsin (Steinhilber and Young, 1979). This report describes the hydrogeologic framework and properties of the regional aquifers in the Hollandale embayment in southeastern Minnesota (fig. 1). Two other reports describing different aspects of the regional aquifers in southeastern Minnesota were also prepared. Delin and Woodward (1984) mapped the potentiometric surface of each regional aquifer, and described the regional flow regimes; and Woodward (1985) presented a summary of 100 years of water use in southeastern Minnesota based upon trends in municipal-well installations and aquifer utilization.
Availability of ground water for irrigation, municipal, or industrial use in the Navajo and Hopi Indian Reservations, Arizona, New Mexico, and Utah
The Navajo and Hopi Indian reservations are located mainly in northeastern Arizona, although the Navajo Indian reservation extends into northwestern New Mexico and southeastern Utah (see location map). The area of this report coincides with the areas of the Navajo and Hopi Indian reservations except in part of New Mexico, where the areas was extended eastward to longitude 108° and southward to Interstate Highway 40 and in southeastern Utah. This investigation was conducted by the U.S. Geological Survey at the request of the Bureau of Indian Affairs. The study was undertaken to evaluate the potential for large-scale ground-water development in the Navajo and Hope Indian Reservations. The results given in this report are intended as preliminary guidelines for the development of ground water in sufficient quantity and of suitable quality for irrigation, municipal, and industrial uses. Data are not included for areas in which less than 25 gal min -1 (gallons per minute) or 95 l min -1 (litres per minute) can be developed.
Maps and interpretation of geochemical anomalies, Chuckwalla Mountains Wilderness Study Area, Riverside County, California
In March 1982, as part of the mineral resource investigations of the area, the U.S. Geological Survey conducted a reconnaissance geochemical survey of the Chuckwalla Mountains Wilderness Study Area (WSA), Riverside County, California. The survey involved collecting 196 heavy-mineral (panned) concentrates from stream sediment (the basis for these maps and the chief basis for the interpretations), the same number of sieved stream-sediment samples, and 25 samples of fresh, altered, or mineralized rocks. A broad regional geochemical framework for mineral resource evaluation was established by sampling a few miles beyond the boundaries of the WSA to include all of the Chuckwalla and Little Chuckwalla Mountains. These geochemical maps are therefore regional maps but of sufficient detail to allow valid conclusions about geochemical anomalies in the WSA. The geochemical data were evaluated in three phases: (1) determining enrichment above background amounts for ore-forming and pathfinder (ore-associated) elements; (2) determining the dispersion patterns of the anomalous elements; and (3) relating the dispersion patterns to geologic environments favorable to ore deposition. This report discusses and interprets geochemical results as they are seen at the reconnaissance stage. Analytical results for all samples collected are released in a U.S. Geological Survey Open-File Report (Adrian and others, 1985). A statistical summary of the data from heavy-mineral concentrates and sieved stream sediments is shown in table 1. The analytical results for selected elements in rock samples are shown in table 2.
Core descriptions, core photographs, physical property logs and surface textural data of sediment cores recovered from the continental shelf of the Monterey Bay National Marine Sanctuary during the research cruises M-1-95-MB, P-2-95-MB, and P-1-97-MB
In response to the 1992 creation of the Monterey Bay National Marine Sanctuary (MBNMS), the United States Geological Survey (USGS) initiated a multiyear investigation of the Sanctuary continental margin. As part of the investigative effort, this report summarizes the shipboard procedures, subsequent laboratory analyses, and data results from three seafloor sampling cruises conducted on the continental shelf between Monterey peninsula, CA and San Francisco, CA. The cruises were conducted in 1995 aboard the NOAA Ship McArthur (M-1-95-MB) and in 1995 and 1997 aboard the R/V Point Sur (P-2-95-MB and P-1-97-MB). Scientists and representatives from the Environmental Protection Agency (EPA), the National Oceanic and Atmospheric Administration (NOAA), the California Department of Fish and Game (CDFG), the University of California Santa Cruz (UCSC), and the San Jose State University Moss Landing Marine Laboratory (SJSU-MLML) supported the research effort. In this report we present sediment descriptions, sediment textural data, physical property logs, station metadata, and photographs of subcores from a total of three hundred and eighty four sample stations. At these sites either a box corer, MultiCore™r, grab sampler or a combination of these sampling devices were used to collect the sea floor sediments. The report is presented in an interactive web-based format with each mapped core station linked to the corresponding description and photo, and to a spreadsheet of surface texture and other sampling data.
Aeromagnetic survey map of the central California Coast Ranges
This aeromagnetic survey was flown as part of a Cooperative Research and Development Agreement (CRADA) with the Pacific Gas and Electric Company and is intended to promote further understanding of the geology and structure in the central California Coast Ranges by serving as a basis for geophysical interpretations and by supporting geological mapping, mineral and water resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on aeromagnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals can commonly mark lithologic or structural boundaries. Bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense magnetic anomalies, but such generalizations must be applied with caution because rocks with more felsic compositions, such as the porphyritic granodiorite-granite of the La Panza Range, and even some sedimentary units, also can cause measurable magnetic anomalies.
Palos Verdes Shelf oceanographic study; data report for observations December 2007–April 2008
Beginning in 1997, the Environmental Protection Agency (EPA) defined a contaminated section of the Palos Verdes Shelf region in southern California as a Superfund Site, initiating a continuing investigation of this area. The investigation involved the EPA, the U.S. Geological Survey (USGS), Science Applications International Corporation (SAIC), Los Angeles County Sanitation Districts (LACSD) data, and other allied agencies. In mid-2007, the Palos Verdes Shelf project team identified the need for additional data on the sediment properties and oceanographic conditions at the Palos Verdes Superfund Site and deployed seven bottom platforms, three subsurface moorings, and three surface moorings on the shelf. This additional data was needed to support ongoing modeling and feasibility studies and to improve our ability to model the fate of the effluent-affected deposit over time. It provided more detail on the spatial variability and magnitude of resuspension of the deposit during multiple storms that are expected to transit the region during a winter season. The operation began in early December 2007 and ended in early April 2008. The goal was to measure the sediment response (threshold of resuspension, suspended-sediment concentrations, and suspended-sediment transport rates) to bed stresses associated with waves and currents. Other objectives included determining the structure of the bottom boundary layer (BBL) relating nearbed currents with those measured at 10 m above bottom (mab) and comparing those with the long-term data from the LACSD Acoustic Doppler Current Profiler (ADCP) deployments for nearbed current speed and direction. Low-profile tripods with high-frequency ADCPs co-located with two of the large tripods were selected for this goal. This report describes the data obtained during the field program, the instruments and data-processing procedures used, and the archive that contains the data sets that have passed our quality-assurance procedures.
Magnetic map of the Irish Hills and surrounding areas, San Luis Obispo County, central California
A magnetic map of the Irish Hills and surrounding areas was created as part of a cooperative research and development agreement with the Pacific Gas and Electric Company and is intended to promote further understanding of the areal geology and structure by serving as a basis for geophysical interpretations and by supporting geological mapping, mineral and water resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on magnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals can be related to either lithologic or structural boundaries. Magnetic susceptibility measurements from the area indicate that bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense magnetic anomalies, but such generalizations must be applied with caution because some sedimentary units also can produce measurable magnetic anomalies. Remanent magnetization does not appear to be a significant source for magnetic anomalies because it is an order of magnitude less than the induced magnetization. The map is a mosaic of three separate surveys collected by (1) fixed-wing aircraft at a nominal height of 305 m, (2) by boat with the sensor at sea level, and (3) by helicopter. The helicopter survey was flown by New-Sense Geophysics in October 2009 along flight lines spaced 150-m apart and at a nominal terrain clearance of 50 to 100 m. Tie lines were flown 1,500-m apart. Data were adjusted for lag error and diurnal field variations. Further processing included microleveling using the tie lines and subtraction of the reference field defined by International Geomagnetic Reference Field (IGRF) 2005 extrapolated to August 1, 2008.
Geochemical, isotopic, and dissolved gas characteristics of groundwater in a fractured crystalline-rock aquifer, Savage Municipal Well Superfund site, Milford, New Hampshire, 2011
Tetrachloroethylene (PCE), a volatile organic compound, was detected in groundwater from deep (more than (>) 300 feet (ft) below land surface) fractures in monitoring wells tapping a crystalline-rock aquifer beneath operable unit 1 (OU1) of the Savage Municipal Well Superfund site (Weston, Inc., 2010). Operable units define remedial areas of contaminant concern. PCE contamination within the fractured-rock aquifer has been designated as a separate operable unit, operable unit 3 (OU3; Weston, Inc., 2010). PCE contamination was previously detected in the overlying glacial sand and gravel deposits and basal till, hereafter termed the Milford-Souhegan glacial-drift (MSGD) aquifer (Harte, 2004, 2006). Operable units 1 and 2 encompass areas within the MSGD aquifer, whereas the extent of the underlying OU3 has yet to be defined. The primary original source of contamination has been identified as a former manufacturing facility—the OK Tool manufacturing facility; hence OU1 sometimes has been referred to as the OK Tool Source Area (New Hampshire Department of Environmental Services, undated). A residential neighborhood of 30 to 40 houses is located in close proximity (one-quarter of a mile) from the PCE-contaminated monitoring wells. Each house has its own water-supply well installed in similar rocks as those of the monitoring wells, as indicated by the New Hampshire State geologic map (Lyons and others, 1997). An investigation was initiated in 2010 by the U.S. Environmental Protection Agency (USEPA) region 1, and the New Hampshire Department of Environmental Services (NHDES) to assess the potential for PCE transport from known contaminant locations (monitoring wells) to the residential wells. The U.S. Geological Survey (USGS) and the NHDES entered into a cooperative agreement in 2011 to assist in the evaluation of PCE transport in the fractured-rock aquifer. Periodic sampling over the last decade by the USEPA and NHDES has yet to detect PCE in groundwater from the residential-supply wells (as of 2012). However, part of assessing the potential for PCE transport involves understanding the origin of the groundwater in the monitoring and residential wells. One of the tools in delineating the movement of groundwater to wells, particularly in complex, highly heterogeneous fractured-rock aquifers, is the understanding of the geochemical and isotopic composition of groundwater (Lipfert and Reeve, 2004; Harte and others, 2012). This report summarizes findings from analyses of geochemical, isotopic, and dissolved gas characteristics of groundwater. Samples of groundwater were collected in 2011 from monitoring wells and nearby residential-supply wells in proximity to OU1.
Aeromagnetic survey map of Sacramento Valley, California
Three aeromagnetic surveys were flown to improve understanding of the geology and structure in the Sacramento Valley. The resulting data serve as a basis for geophysical interpretations, and support geological mapping, water and mineral resource investigations, and other topical studies. Local spatial variations in the Earth's magnetic field (evident as anomalies on aeromagnetic maps) reflect the distribution of magnetic minerals, primarily magnetite, in the underlying rocks. In many cases the volume content of magnetic minerals can be related to rock type, and abrupt spatial changes in the amount of magnetic minerals commonly mark lithologic or structural boundaries. Bodies of serpentinite and other mafic and ultramafic rocks tend to produce the most intense positive magnetic anomalies (for example, in the northwest part of the map). These rock types are the inferred sources, concealed beneath weakly magnetic, valley-fill deposits, of the most prominent magnetic features in the map area, the magnetic highs that extend along the valley axis. Cenozoic volcanic rocks are also an important source of magnetic anomalies and coincide with short-wavelength anomalies that can be either positive (strong central positive anomaly flanked by lower-amplitude negative anomalies) or negative (strong central negative anomaly flanked by lower-amplitude positive anomalies), reflecting the contribution of remanent magnetization. Rocks with more felsic compositions or even some sedimentary units also can cause measurable magnetic anomalies. For example, the long, linear, narrow north-trending anomalies (with amplitudes of <50 nanoteslas [nT]) along the western margin of the valley coincide with exposures of the Mesozoic Great Valley sequence. Note that isolated, short-wavelength anomalies, such as those in the city of Sacramento and along some of the major roads, are caused by manmade features.
Mercury in U.S. coal—Priorities for new U.S. Geological Survey studies
In 2011, the U.S. Environmental Protection Agency (EPA) introduced emissions standards, known as Mercury and Air Toxics Standards (MATS), for a range of toxic constituents from coal-fired utility power stations and other combustion sources. This report presents the findings of an expert panel convened in September 2014 to assess the role of the U.S. Geological Survey (USGS) in new coal investigations that would be useful to stakeholders under MATS. Panel input is provided as summaries of responses to a questionnaire distributed to participants. The panel suggests that the USGS continue its work on trace elements in coal and include more information about delivered coals and boiler feed coals, in comparison to previous USGS compilations that emphasized sampling representative of coals in the ground. To be useful under multipollutant regulatory standards, investigation of a range of constituents in addition to mercury would be necessary. These include other toxic metals proposed for regulation, such as arsenic, nickel, cadmium, and chromium, as well as the halogens chlorine and fluorine, which upon emission form harmful acid gases. Halogen determinations are also important because they influence mercury speciation in flue gas, which allows the effectiveness of mercury controls to be assessed and predicted. The panel suggests that the Illinois Basin and the Powder River Basin should have the highest priority for new coal quality investigations in the near term by the USGS, on the basis of current economic conditions and overall economic importance, respectively. As a starting point for new investigations, brief summaries of the distribution of mercury in each coal basin, and their potential for further investigation, are presented.
Water-quality distributions in the East Branch Black River near the Chemical Recovery Systems site in Elyria, Ohio, 2021
Autonomous underwater vehicles are uniquely designed to provide spatially dense water-quality data along with bathymetry and velocimetry. The U.S. Environmental Protection Agency Region 5 requested technical assistance from the U.S. Geological Survey in support of ongoing investigations at the Chemical Recovery Systems site to collect spatially dense water-quality and bathymetry data in the East Branch Black River in Elyria, Ohio. This report was prepared in cooperation with the U.S. Environmental Protection Agency to present the results of the autonomous underwater vehicle survey near the Chemical Recovery Systems site on March 22, 2021. Plots of distributions of water temperature, specific conductance, pH, and dissolved oxygen are presented that may help guide and focus future U.S. Environmental Protection Agency efforts at the site to determine the degree of groundwater/surface-water interaction.
Preliminary report on a lead-zinc occurrence at Berg Basin, Wrangell district, southeastern Alaska
A brief examinatin of lead-zinc occurrence at Berg Basin, Wrangell district, southeastern Alaska, was undertaken in 1947 as part of the U.S. Geological Survey's program of minerals investigations in Alaska. No lead-zinc ore body has yet been proved at Berg Basin, but because of recent interest in that area this preliminary report has been prepared for the purpose of making available immediately all data collected to date. A more complete report is in preparation.
Geology of the Dry Valley quadrangle, Idaho; a preliminary report
The Dry Valley quadrangle is one of seven 71-minute quadrangles in southeastern Idaho being mapped by the U. S. Geological Survey as part of an investigation of the western phosphate field. This work was done on behalf of the Division of Raw Materials of the Atomic Energy Commission. Most of the quadrangle was mapped on a new 1:12,000 topographic base during the summer and fall of 1950 by E. R. Cressman and R. A. Gulbrandsen with the assistance of K. B. Krauskopf, K. Lutz, and J. W. Hill. The field work was completed in the fall of 1951 by Cressman and assisted by R. G. Waring and M. A. Warner. This quadrangle is the NEI of the Slug Creek 15-minute quadrangle, which was mapped by Mansfield (1927) at a scale of 1:62,500.