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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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At least 649 records · Page 36Linked to original sources

USGS1985

Simulated effects of increased recharge on the ground-water flow system of Yucca Mountain and vicinity, Nevada-California

A study was performed to assess the potential effects of changes in future climatic conditions on the groundwater system in the vicinity of Yucca Mountain, the site of a potential mined geologic repository for high-level nuclear wastes. These changes probably would result in greater rates of precipitation and, consequently, greater rates of recharge. The study was performed by simulating the groundwater system, using a two-dimensional, finite-element, groundwater flow model. The simulated position of the water table rose as much as 130 meters near the U.S. Department of Energy 's preferred repository area at Yucca Mountain for a simulation involving a 100-percent increase in precipitation compared to modern-day conditions. Despite the water table rise, no flooding of the potential repository would occur at its current proposed location. According to the simulation, springs would discharge south and west of Timber Mountain, along Fortymile Canyon, in the Amargosa Desert near Lathrop Wells and Franklin Lake playa, and near Furnace Creek Ranch in Death Valley, where they presently discharge. Simulated directions of groundwater flow paths near the potential repository area generally would be the same for the baseline (modern-day climate) and the increased-recharge simulations, but the magnitude of flow would increase by 2 to 4 times that of the baseline-simulation flow. (USGS)

California, Nevada↗

USGS1969

The relationship between fluids in some fresh alpine-type ultramafics and possible modern serpentinization, western United States

Calcium hydroxide waters issue from four partly serpentinized Alpine-type ultramafic bodies in the western United States. The occurrence of calcium-hydroxide-type water is restricted to fresh Alpine-type ultramafic rocks. The calcium hydroxide waters are unsaturated with Mg end-member olivine and pyroxene but supersaturated with Mg end-member brucite and serpentine and thus have chemical potentials to cause Serpentinization. The calcium hydroxide waters are isotopically similar to the common magnesium bicarbonate meteoric waters peculiar to ultramafic rocks and serpentinites. Some Serpentinization is apparently a near-surface phenomenon occurring at present. The Serpentinization takes place at nearly constant composition, except for loss of CaO. © 1969, The Geological Society of America, Inc.

Geological Society of America Bulletin↗

USGS2012

Kinematics of the New Madrid seismic zone, central United States, based on stepover models

Seismicity in the New Madrid seismic zone (NMSZ) of the central United States is generally attributed to a stepover structure in which the Reelfoot thrust fault transfers slip between parallel strike-slip faults. However, some arms of the seismic zone do not fit this simple model. Comparison of the NMSZ with an analog sandbox model of a restraining stepover structure explains all of the arms of seismicity as only part of the extensive pattern of faults that characterizes stepover structures. Computer models show that the stepover structure may form because differences in the trends of lower crustal shearing and inherited upper crustal faults make a step between en echelon fault segments the easiest path for slip in the upper crust. The models predict that the modern seismicity occurs only on a subset of the faults in the New Madrid stepover structure, that only the southern part of the stepover structure ruptured in the A.D. 1811–1812 earthquakes, and that the stepover formed because the trends of older faults are not the same as the current direction of shearing.

Geology↗

USGS2013

Generalized surficial geologic map of the Fort Irwin Area, San Bernardino County, California

The geology and landscape of the Fort Irwin area, typical of many parts of the Mojave Desert, consist of rugged mountains separated by broad alluviated valleys that form the main coarse-resolution features of the geologic map. Crystalline and sedimentary rocks, Mesozoic and older in age, form most of the mountains with lesser accumulations of Miocene sedimentary and volcanic rocks. In detail, the area exhibits a fairly complex distribution of surficial deposits resulting from diverse rock sources and geomorphology that has been driven by topographic changes caused by recent and active faulting. Depositional environments span those typical of the Mojave Desert: alluvial fans on broad piedmonts, major intermittent streams along valley floors, eolian sand dunes and sheets, and playas in closed valleys that lack through-going washes. Erosional environments include rocky mountains, smooth gently sloping pediments, and badlands in readily eroded sediment. All parts of the landscape, from regional distribution of mountains, valleys, and faults to details of degree of soil development in surface materials, are portrayed by the surficial geologic map. Many of these attributes govern infiltration and recharge, and the surface distribution of permeable rock units such as Miocene sedimentary and volcanic rocks provides a basis for evaluating potential groundwater storage. Quaternary faults are widespread in the Fort Irwin area and include sinistral, east-striking faults that characterize the central swath of the area and the contrasting dextral, northwest-striking faults that border the east and west margins. Bedrock distribution and thickness of valley-fill deposits are controlled by modern and past faulting, and faults on the map help to identify targets for groundwater exploration.

California↗

USGS2018

Chemical and isotopic characteristics of methane in groundwater of Ohio, 2016

In 2016, the U.S. Geological Survey, in cooperation with the Ohio Water Development Authority, investigated the hydrogeologic setting, chemical and isotopic characteristics, and origin of methane in groundwater of Ohio. Understanding the occurrence and distribution of methane in groundwater is important in terms of public safety because methane in water wells can pose a risk of explosion. In addition, documenting the chemical and isotopic characteristics of methane in groundwater can make an important contribution to future stray gas investigations. Water samples were collected from 15 domestic water wells known to produce methane, which were in 12 counties in diverse parts of Ohio. The wells were 75–345 feet deep and tapped a range of aquifer types, including glacial deposits and bedrock of Upper Ordovician, Upper Devonian, Lower Mississippian, and Pennsylvanian ages. Although the hydrogeologic settings were varied, there was a broad similarity among the well sites in that the bedrock was predominantly shale and the glacial deposits were predominantly clay. The wells were sampled for dissolved inorganic constituents; dissolved organic carbon; methane and other dissolved gases; stable isotopes (carbon, hydrogen, and oxygen) of methane, water, and dissolved inorganic carbon; and carbon-14 of methane. Gas composition and stable isotopes of methane were used to differentiate thermogenic and microbial methane. The degree of fractionation of hydrogen and carbon isotopes was used to evaluate the pathway of microbial methanogenesis (carbon dioxide [CO 2 ] reduction or acetate fermentation) and the effects of secondary processes such as oxidation, mixing, and migration. The concentration of carbon-14 of methane was used to evaluate the relative age of the carbon source. The quality of water from the 15 wells differed greatly; water types ranged from CaMgHCO 3 to NaCl, and total dissolved solids concentrations ranged from 318 to 2,940 milligrams per liter (mg/L). Methane concentrations ranged from 1.2 to 120 mg/L. Of the 15 samples, 12 had methane concentrations greater than 28 mg/L, the level that can pose a risk of explosion. Of the 15 samples, 12 had chemical and isotopic characteristics or "signatures" consistent with microbial methane formed by CO 2 reduction. CO 2 reduction is commonly associated with microbial degradation of organic matter in anaerobic aquifers and with the formation of microbial shale gas and coalbed methane along margins of sedimentary basins. Two of 15 samples were interpreted as having a component of thermogenic methane based on the δ 13 C of methane (−50.96 and −47.74 parts per thousand [per mil]) and gas dryness (28 and 5). One of 15 samples (from the shallowest well) had chemical and isotopic characteristics consistent with methane oxidation by sulfate reduction based on light δ 13 C of dissolved inorganic carbon (−31.6 per mil) and evidence of sulfate reduction in terms of the odor and appearance of the water. For the 12 samples interpreted as microbial methane formed by CO 2 reduction, the δ 13 C of methane varied from −75 to −56 per mil. Multiple samples from the same aquifer demonstrated a general trend of increasing δ 13 C of methane with depth. Samples with lighter δ 13 C of methane (−75 to −62 per mil) were from shallower wells (or wells with shallow open intervals), and the isotopic signature of the water was consistent with modern or postglacial groundwater recharge. Three samples with heavier δ 13 C of methane (−61 to −56 per mil) were from deeper wells or more confined aquifers where the isotopic signature of water was consistent with older (glacial) recharge. In addition, δ 13 C of dissolved inorganic carbon was enriched (+12 to +18.9 per mil), and carbon-14 of methane was consistent with carbon associated with Paleozoic bedrock or older glacial deposits. These observations are generally consistent with increased Rayleigh-type fractionation at greater depths; however, other interpretations are possible. Isotopic signatures can be ambiguous, especially in areas with complex geologic histories that include multiple episodes of migration, mixing, and (or) oxidation. Many of the wells were in proximity to multiple potential natural and anthropogenic pathways of methane migration; however, it is not possible to determine if the methane in any of the wells is related to human activities based on the chemical and isotopic data collected for this study.

Ohio↗

USGS2012

Stable isotope deltas: Tiny, yet robust signatures in nature

Although most of them are relatively small, stable isotope deltas of naturally occurring substances are robust and enable workers in anthropology, atmospheric sciences, biology, chemistry, environmental sciences, food and drug authentication, forensic science, geochemistry, geology, oceanography, and paleoclimatology to study a variety of topics. Two fundamental processes explain the stable isotope deltas measured in most terrestrial systems: isotopic fractionation and isotope mixing. Isotopic fractionation is the result of equilibrium or kinetic physicochemical processes that fractionate isotopes because of small differences in physical or chemical properties of molecular species having different isotopes. It is shown that the mixing of radioactive and stable isotope end members can be modelled to provide information on many natural processes, including 14C abundances in the modern atmosphere and the stable hydrogen and oxygen isotopic compositions of the oceans during glacial and interglacial times. The calculation of mixing fractions using isotope balance equations with isotope deltas can be substantially in error when substances with high concentrations of heavy isotopes (e.g. 13C, 2H, and 18O ) are mixed. In such cases, calculations using mole fractions are preferred as they produce accurate mixing fractions. Isotope deltas are dimensionless quantities. In the International System of Units (SI), these quantities have the unit 1 and the usual list of prefixes is not applicable. To overcome traditional limitations with expressing orders of magnitude differences in isotope deltas, we propose the term urey (symbol Ur), after Harold C. Urey, for the unit 1. In such a manner, an isotope delta value expressed traditionally as−25 per mil can be written as−25 mUr (or−2.5 cUr or−0.25 dUr; the use of any SI prefix is possible). Likewise, very small isotopic differences often expressed in per meg ‘units’ are easily included (e.g. either+0.015 ‰ or+15 per meg can be written as+15 μUr.

Isotopes in Environmental and Health Studies↗

USGS1986

Two-hundred years of hydrogeology in the United States

The Hydrogeology Division of the Geological Society of America (GSA) sponsored a symposium entitled ' Hydrogeology in the United States, 1776- 1976 ' at the annual meeting of the GSA on November 9, 1976. The symposium was organized to provide a forum for discussion of major eras in the history of American hydrogeology and to contribute to the bicentennial celebration of the founding of the United States. Presentations were broken down into 3 sections: The Early Era (with a tribute to Oscar E. Meinzer), 1776-1920; Meinzer Era, 1910-1940; and the Modern Era (including scientific advantages; the quantification of hydrogeology; geochemistry; surface and borehole geophysics; and hydrogeology, policy, and politics) 1940-1976. (Lantz-PTT)

Open-File Report↗

USGS1976

Cenozoic deposits of southeastern New Mexico and an outline of the history of evaporite dissolution

Sedimentary records of Cenozoic history in southeastern New Mexico begin with the Ogallala Formation of Miocene and Pliocene age. Later records include the Gatuna Formation of early or middle Pleistocene age, Mescalero caliche, an informal term, of middle Pleistocene age, and fluvial deposits of late Pleistocene age but there are many gaps in the record. The modern landscape is the result of erosion and deposition in climates that have ranged from semihumid to semiarid as well as dissolution of soluble rocks in Permian formations in the subsurface. This dissolution may have begun as early as Jurassic time and has continued intermittently to the present.

New Mexico↗

USGS1961

Subaerially carved Arctic seavalley under a modern epicontinental sea

A shallow seavalley , averaging 6 feet in relief, extends from the mouth of Ogotoruk Creek, northwest Alaska, for 15 miles across the floor of the Chukchi Sea to a depth of 135 feet. The seavalley is considered to be a drowned subaerial valley of Pleistocene age, which was excavated on an eustatically emerged epicontinental shelf during periods of glacially depressed sea level.

Bulletin of the Geological Society of America↗

USGS1984

APPLICATION OF SPATIAL INFORMATION TECHNOLOGY TO PETROLEUM RESOURCE ASSESSMENT ANALYSIS.

Petroleum resource assessment procedures require the analysis of a large volume of spatial data. The US Geological Survey (USGS) has developed and applied spatial information handling procedures and digital cartographic techniques to a recent study involving the assessment of oil and gas resource potential for 74 million acres of designated and proposed wilderness lands in the western United States. The part of the study which dealt with the application of spatial information technology to petroleum resource assessment procedures is reviewed. A method was designed to expedite the gathering, integrating, managing, manipulating and plotting of spatial data from multiple data sources that are essential in modern resource assessment procedures.

Conference Paper↗

USGS2001

Interglacial theme and variations: 500 k.y. of orbital forcing and associated responses from the terrestrial and marine biosphere, U.S. Pacific Northwest

Sediments collected off northern California by Ocean Drilling Program Leg 167 contain time series that show strong, orbitally driven insolation forcing of surface oceanographic conditions. Orbital forcing caused a strong response in the distribution of major terrestrial vegetation but a less predictable response for primary productivity offshore. Terrestrial vegetation responded primarily to regional sea surface temperature (SST). Coastal ocean productivity appears highest when SST is moderately high, not during peak interglacial conditions nor during insolation maxima. When individual interglacial intervals are examined closely, each has a different signature. Two of six interglacials (MIS [marine isotope stage] 5 and MIS 11) have higher SST than modern conditions, but each elicits a different response from the terrestrial and marine communities. The type of vegetation and the strength of upwelling vary between interglacials, depending on the relative strength of factors that drive the warming, including insolation, ice-cap size, and level of greenhouse gases.

California↗

USGS2021

Bottom-up and top-down control on hydrothermal resources in the Great Basin: An example from Gabbs Valley, Nevada

The Great Basin in the western United States hosts various hydrothermal systems, including both active geothermal systems and ancient systems preserved as mineral deposits. New magnetotelluric and structural geologic data were collected in the Gabbs Valley area of western Nevada to demonstrate the advantage of imaging the full crustal column below known hydrothermal systems. Three-dimensional models are developed and jointly interpreted where the key findings are bottom-up and top-down controls on hydrothermal systems. Bottom-up control is dictated by weaknesses in the brittle-ductile transition that allow hydrothermal fluids to propagate into the crust; these are often collocated with Miocene volcanic structures. Top-down control is dominated by modern Walker Lane and Basin and Range tectonics that control fluid transport through the middle and upper crust. This study demonstrates that the characterization of regional mineral and geothermal resources is better informed by imaging lower crustal structures and preferential pathways to the surface.

Geophysical Research Letters↗

USGS2011

Digitized data from ground geophysical surveys in Afghanistan: A website for distribution of data

This document describes the process of digitization of a 1974 report on geophysical work undertaken by Soviet geophysicists in southern and eastern Afghanistan. These data, uncovered in Afghanistan, represent magnetic and electrical ground surveys for which locations are not well defined. Due to lack of location information, these surveys were georeferenced using the cities, rivers, and surrounding geology found on the maps used to plot survey locations. A geologic map found in the Soviet report contains profile lines that correspond to the geophysical maps, allowing these data to be georeferenced. The profiles correspond to sets of resistivity, chargeabiliy, and magnetic data. Some datasets were presented as graphs and needed to be gridded into a useable image. Only the vertical component of the magnetic field was collected, so conversion to total field anomaly was necessary. The magnetic data were collected in either gammas or milliorstead, both of which required conversion to standard SI units. To be useful to modern studies, the datasets and images contained in this report have been digitized, georeferenced, and in some cases converted into computer-ready formats.

Open-File Report↗

USGS1997

Future of the US National Strong-Motion Program

These reports are presented in response to a charge of the Earthquake Hazards Reduction Program (EHRP) Program Council of the U.S. Geological Survey to 'define the future of the USGS National Strong-Motion Program (NSMP)' (Appendix A). The council requested that a 'Vision Paper' and an 'Options Document' be prepared. Each of these reports is a separate document. The 'Executive Summary' of both reports is presented here under separate cover. The content of the reports and the executive summary is organized to the extent possible according to the main charges of the EHRP Program Council. Detailed evaluation of charges and questions posed by the Council with the benefit of modern GIS tools and the recent deliberations of three national workshops have yielded substantial new insight regarding the status of strong-motion measurement in the US. These reports are intended as an objective evaluation of the nation's need and capability to record the next major earthquake at locations of most significance for public safety.

Open-File Report↗

USGS1997

Executive summary of vision and options for the future of the US National Strong-Motion Program

Open-File Report↗

USGS2007

Relation of Chlorofluorocarbon Ground-Water Age Dates to Water Quality in Aquifers of West Virginia

The average apparent age of ground water in fractured-bedrock aquifers in West Virginia was determined using chlorofluorocarbon (CFC) dating methods. Since the introduction of CFC gases as refrigerants in the late 1930s, atmospheric concentrations have increased until production ceased in the mid-1990s. CFC dating methods are based on production records that date to the early 1940s, and the preservation of atmospheric CFC concentrations in ground water at the time of recharge. As part of the U.S. Geological Survey (USGS) National Water-Quality Assessment (NAWQA) and Ambient Ground-Water Monitoring Network (AGN) programs in West Virginia from 1997 to 2005, 80 samples from the Appalachian Plateaus Physiographic Province, 27 samples from the Valley and Ridge Physiographic Province, and 5 samples from the Ohio River alluvial aquifers were collected to estimate ground-water ages in aquifers of West Virginia. Apparent CFC ages of water samples from West Virginia aquifers ranged from 5.8 to 56 years. In the Appalachian Plateaus, topographically driven ground-water flow is evident from apparent ages of water samples from hilltop, hillside, and valley settings (median apparent ages of 12, 14, and 25 years, respectively). Topographic setting was the only factor that was found to be related to apparent ground-water age in the Plateaus at the scale of this study. Similar relations were not found in Valley and Ridge aquifers, indicating that other factors such as bedding or geologic structure may serve larger roles in controlling ground-water flow in that physiographic province. Degradation of CFCs was common in samples collected from methanogenic/anoxic aquifers in the Appalachian Plateaus and suboxic to anoxic aquifers in the Valley and Ridge. CFC contamination was most common in Ohio River alluvial aquifers and carbonate units of the Valley and Ridge, indicating that these highly transmissive surficial aquifers are the most vulnerable to water-quality degradation and may contain wastewater from domestic or industrial sources with CFC concentrations greater than modern atmospheric levels. However, based on a lack of detections of the volatile organic compounds analyzed for in most of the water samples collected for this and similar USGS investigations, ground-water resources of West Virginia used for public and private consumption do not appear to be routinely affected by anthropogenic activities despite their young apparent age.

Scientific Investigations Report↗

USGS2014

High-resolution topography and geomorphology of select archeological sites in Glen Canyon National Recreation Area, Arizona

Along the Colorado River corridor between Glen Canyon Dam and Lees Ferry, Arizona, located some 25 km downstream from the dam, archaeological sites dating from 8,000 years before present through the modern era are located within and on top of fluvial and alluvial terraces of the prehistorically undammed river. These terraces are known to have undergone significant erosion and retreat since emplacement of Glen Canyon Dam in 1963. Land managers and policy makers associated with managing the flow of the Colorado River are interested in understanding how the operations of Glen Canyon Dam have affected the archeological sites associated with these terraces and how dam-controlled flows currently interact with other landscape-shaping processes. In 2012, the U.S. Geological Survey initiated a research project in Glen Canyon to study the types and causes of erosion of the terraces. This report provides the first step towards this understanding by presenting comparative analyses on several types of high-resolution topographic data (airborne lidar, terrestrial lidar, and airborne photogrammetry) that can be used in the future to document and analyze changes to terrace-based archaeological sites. Herein, we present topographic and geomorphologic data of four archaeological sites within a 14 km segment of Glen Canyon using each of the three data sources. In addition to comparing each method’s suitability for adequately representing the topography of the sites, we also analyze the data within each site’s context and describe the geomorphological processes responsible for erosion. Our results show that each method has its own strengths and weaknesses, and that terrestrial and airborne lidar are essentially interchangeable for many important topographic characterization and monitoring purposes. However, whereas terrestrial lidar provides enhanced capacity for feature recognition and gully morphology delineation, airborne methods (whether by way of laser or optical sensors) are better suited for reach- and regional-scale mapping. Our site-specific geomorphic analyses of the four archeological sites indicate that their current topographical conditions are a result of different and sometimes competing erosional agents, including bedrock- and terrace-based overland flow, fluvial-induced terrace bank collapse, and alluvial-fan-generated debris flows. Although the influences of anthropogenic-induced erosion from dam operations are not specifically analyzed in this report, we do identify geomorphic settings where dam operations are either more or less likely to affect archeological site stability. This information can be used to assist with future monitoring efforts of these sites and identification of similar conditions for other archeological sites along the Colorado River corridor in Glen Canyon.

Arizona↗

USGS2023

Groundwater quality near the Montebello Oil Field, Los Angeles County, California

Groundwater quality and potential sources and migration pathways of chemical constituents associated with hydrocarbon-bearing formations were assessed by the U.S. Geological Survey for the California State Water Resources Control Board Oil and Gas Regional Monitoring Program (RMP). Groundwater samples were collected as part of the RMP from 21 preexisting wells used for public supply, monitoring, or irrigation in and near the Montebello Oil Field and analyzed for constituents associated with hydrocarbon-bearing formations and constituents used to identify recently recharged groundwater and older groundwater. The newly collected RMP data were supplemented with historical sample data from 849 groundwater wells and analyzed with respect to explanatory factors that have the potential to influence water quality. Potential sources and migration pathways of fluids (water, gas, or oil) from hydrocarbon-bearing formations that could affect groundwater quality in the Montebello Oil Field include large volumes of recycled produced water (water withdrawn from an oil well and brought to the surface that may include oil, water, and gas from the geologic formation and water or gas injected for enhanced recovery) that have been reinjected since the 1960s to enhance oil production, oil and gas wells with well-integrity issues, and oil and gas wells with an uncemented annulus that intersects groundwater resource zones. Trace amounts of dissolved petroleum hydrocarbons, thermogenic gas (propane through pentane range), or both, were detected in seven groundwater samples collected in 2014 and 2018 as part of the RMP. Five of those samples also contained manufactured volatile organic compounds and at least some modern-age groundwater (recharged during or after 1953), indicating that the hydrocarbons could have originated from surficial, or shallow, sources unrelated to oil and gas development. Two samples contained low concentrations of petroleum hydrocarbons (less than 0.1 microgram per liter) and did not contain detections of manufactured volatile organic compounds in pre-modern groundwater. These samples were collected from relatively deep wells (greater than 140 meters below land surface) with perforations completed in marine sediments that may contain water with similar compositions to produced water. The RMP sample results and available historical data in and near the Montebello Oil Field did not provide conclusive evidence that oil and gas development has adversely affected groundwater resources. All samples with detectable petroleum hydrocarbons, thermogenic gases, or both, were collected from sites that also are within 500 meters of anthropogenic hydrocarbon sources not associated with oil and gas development or sources. In addition, naturally occurring sources of hydrocarbons that exist at intervals shallower than, or are in areas outside of, economically productive oil- and gas-producing zones could affect groundwater quality. A definitive analysis of relations of groundwater quality to potential anthropogenic and natural explanatory factors was not possible because of the low density of new and historical sampling data, particularly in parts of the Montebello Oil Field where the largest relative risks to groundwater from hydrocarbon-bearing formations exist. Areas to consider for more detailed monitoring and analysis in the future that may present the largest relative potential risks to groundwater quality include (1) areas downgradient from historical surface ponds and sumps and (2) areas with co-located high net injection (oil reservoir injection exceeds production), old oil and gas wells that may be more likely to develop well-integrity issues than newer wells, and oil and gas wells with uncemented boreholes intersecting groundwater zones. To help fill gaps resulting from sparse groundwater wells, temperature and resistivity borehole log data could be analyzed to locate anomalies that identify potential areas where relatively warm or saline water from deeper hydrocarbon-bearing formations is present in groundwater.

California↗