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At least 883 records · Page 49Linked to original sources
USGS2012

Water-quality, bed-sediment, and discharge data for the Mississippi River-Gulf Outlet and adjacent waterways, southeastern Louisiana, August 2008 through December 2009

The Mississippi River-Gulf Outlet navigation channel (MRGO) was constructed in the early 1960s to provide a safer and shorter route between the Gulf of Mexico and the Port of New Orleans for deep-draft, ocean-going vessels and to promote the economic development of the Port of New Orleans. In 2006, the U.S. Army Corps of Engineers developed a plan to de-authorize the MRGO. The plan called for a rock barrier to be constructed across the MRGO near Bayou La Loutre. In 2008, the U.S. Geological Survey, in cooperation with the Louisiana Coastal Area Science and Technology Program began a study to document the impacts of the rock barrier on water-quality and flow before, during, and after its construction. Water-quality, bed-sediment, and discharge data were collected in the MRGO and adjacent water bodies from August 2008 through December 2009.

Louisiana↗
USGS1960

Geology and ore deposits of the Klondike Ridge area, Colorado

The region described in this report is in the northeastern part of the Colorado Plateau and is transitional between two major structural elements. The western part is typical of the salt anticline region of the Plateau, but the eastern part has features which reflect movements in the nearby San Juan Mountains. There are five major structural elements in the report area: the Gypsum Valley anticline, Dry Creek Basin, the Horse Park fault block, Disappointment Valley, and the Dolores anticline. Three periods of major uplift are recognized In the southeastern end of the Gypsum Valley anticline. Each was followed by collapse of the overlying strata. Erosion after the first two periods removed nearly all topographic relief over the anticline; erosion after the last uplift has not yet had a profound effect on the topography except where evaporite beds are exposed at the surface. The first and greatest period of salt flow and anticlinal uplift began in the late Pennsylvanian and continued intermittently and on an ever decreasing scale into the Early Cretaceous. Most movement was in the Permian and Triassic periods. The second period of uplift and collapse was essentially contemporaneous with widespread tectonic activity on. the northwestern side of the San Juan Mountains and may have Occurred in the Oligocene and Miocene epochs. Granogabbro sills and dikes were intruded during the middle or upper Tertiary in Disappointment Valley and adjoining parts of the Gypsum Valley and Dolores anticlines. The third and mildest period of uplift occurred in the Pleistocene and was essentially contemporaneous with the post-Hinsdale uplift of the San Juan Mountains. This uplift began near the end of the earliest, or Cerro, stage of glaciation. Uranium-vanadium, manganese, and copper ore as well as gravel have been mined in the Klondike district. All deposits are small, and few have yielded more than 100 tons of ore. Most of the latter are carnotite deposits. Carnotite occurs in the lower part of the basal sandstone unit of the Salt Wash member of the Morrison formation. Most deposits are in a narrow, elongate mineral belt' that cuts obliquely across Klondike Ridge. The remaining deposits probably form a second 'mineral belt' lying about ? mile to the north. Manganese and copper deposits show both stratigraphic and structural controls of mineralization. Most manganese deposits are in red beds near Tertiary faults; most copper deposits, on the other hand, are in brown sandstone, limestone, or gray-green shale and, like manganese, are in or near Tertiary faults. The manganese and copper deposits are hydrothermal in origin and were formed in the roots of an ancient hot springs system, now deeply eroded. The ore-bearing solutions probably consisted of dilute, carbonate-sulfate ground water heated by the near-surface intrusion of small bodies of igneous rock. These solutions obtained their metals by leaching the wallrock; little, if any, material was added by the intrusives. The deposits were formed near the surface under conditions of hydrostatic pressure, and temperatures and pressures in the ore-bearing solutions were probably low. The early solutions were weakly alkaline and reducing in character. A convection cell was established as mineralization progressed, and surface water mingled at depth with the solutions. As a result of mixing and oxidation, the pH of the solution decreased in later stages of mineralization and the Eh rose.

Open-File Report↗
USGS2009

Bathymetric, Velocity, Streamflow, and Dissolved Oxygen Data on the Pee Dee River near Bostick Boat Landing, Florence County, South Carolina, May-August 2007

Santee Cooper is planning to construct an electricity generating station in southeastern Florence County near the Kingsburg community. As part of this project, a water-intake structure will be constructed on the Pee Dee River near the Bostick Boat Landing, which is located east of the intersection of State secondary roads S-21-57 and S-21-66. Velocity, bathymetric, and dissolved oxygen data are needed to help determine the location for the water-intake structure. The U.S. Geological Survey (USGS), in cooperation with Santee Cooper, collected these data at three different flow regimes during the period of May through August 2007. Data were collected along 15 transects located at 50-foot intervals starting 400 feet upstream from the boat landing and continuing to 300 feet downstream from the boat landing. All data were geographically referenced using a differentially corrected global positioning system (GPS).

South Carolina↗
USGS2022

Evaluation of the Bushy Park Reservoir three-dimensional hydrodynamic and water-quality model, South Carolina, 2012–15

The Bushy Park Reservoir is a relatively shallow impoundment in southeastern South Carolina. The reservoir, located under a semi-tropical climate, is the principal water supply for the city of Charleston, South Carolina, and the surrounding areas including the Bushy Park Industrial Complex. Although there was an adequate supply of freshwater in the reservoir in 2022, water-quality concerns are present over taste-and-odor and saltwater-intrusion issues. From 2013 to 2015, the U.S. Geological Survey (USGS), in cooperation with the Charleston Water System, engaged in a multi-year study of the hydrology and hydrodynamics of Bushy Park Reservoir to better understand factors affecting water-quality conditions in the reservoir. As part of this study, Charleston Water System worked with Tetra Tech, Inc., a consulting and engineering firm, to develop a Bushy Park Reservoir hydrodynamic and water-quality modeling framework, built upon earlier efforts by both Tetra Tech and the U.S. Army Corps of Engineers. At the completion of the new modeling framework, the USGS was requested to evaluate the calibrated hydrodynamic and water-quality model. The Bushy Park Reservoir Environmental Fluid Dynamics Code (EFDC) model was calibrated for the time period from January 1, 2012, to December 31, 2015. The general modeling approach for the newly revised modeling framework, as briefly detailed in this report, was developed with EFDC. The EFDC is a grid-based modeling package that can simulate three-dimensional flow, transport, and water quality in surface-water systems. This report evaluated the capacity of Tetra Tech’s Bushy Park EFDC model to simulate water discharge, water circulation, surface elevations, temperature, salinity, and other water-quality parameters. The USGS model review focused specifically on the following criteria: (1) determine if the model, with additional effort, could be developed into an adequate planning tool for Bushy Park Reservoir; (2) assess the capacity of the model to specifically address water-quality issues in the reservoir related to taste-and-odor and saltwater intrusions; and, (3) evaluate three preliminary water-management scenarios related to reduced water withdrawals in the reservoir and the effect on saltwater intrusion. Overall, the model was able to simulate discharge, flow velocity, and water-surface elevations with generally good agreement between the simulated and measured values. Specifically, the model was able to demonstrate good agreement for discharge at two USGS continuous discharge locations (USGS station 02172002; USGS station 02172040), with Wilmott index of agreements of 0.86 and 0.75, respectively. A total of seven USGS streamgages, located on the West Branch of the Cooper River, Durham Canal, and the Cooper River, were available for water-surface elevations, with index of agreements ranging from 0.74 to 0.99. However, model-simulated water-surface elevation ranges were appreciably high (compared to measured ranges) for two locations near Pinopolis Dam, farthest upstream on the West Branch of the Cooper River. This result may indicate that too much simulated tidal energy propagated through the model domain. For water temperature, 16 calibration stations were available for at least part of the 4-year simulation. The index of agreement range for temperature comparisons was from 0.95 to 1.00, indicating excellent agreement between the measured and simulated results. One of the primary future applications for the Bushy Park Reservoir EFDC model is to determine the extent of saltwater intrusions. A wide range in the salinity prediction quality was simulated with the model. The prediction quality ranged from an index of agreement of 0.15 at Cooper River approximately 2.75 miles southeast of the Tee, South Carolina, to 0.92 at West Branch Cooper River near Moncks Corner, South Carolina. Although the model did not accurately simulate some of the larger salinity deviations resulting during individual hydrologic events, the seasonal salinity trends were adequately simulated with the model during the study period (2012–15). Therefore, it may be difficult to simulate extreme hydrologic events, such as during large storms, where high salinity water is exchanged with Bushy Park Reservoir. There was agreement in model simulation with the measured data either on the quantitative index of agreement values or qualitative agreement in the seasonal salinity data trends. For water quality, the index of agreement values were generally low for total nitrogen, ammonia, nitrate, total Kjeldahl nitrogen, total phosphorus, and orthophosphate. Although general trends were adequately simulated at specific stations, particularly for Bushy Park Reservoir, the model-simulated fit was low across all the constituents described above with index of agreements usually below 0.50. A limitation for simulating nutrient concentrations across the model domain was the lack of characterization for the constituents directly entering Bushy Park Reservoir, or the lack of data directly attributed to the boundary condition (for example, the Cooper River). The other two calibrated water-quality constituents (besides the nutrients mentioned above) were dissolved oxygen and chlorophyll a . Dissolved oxygen varied from index of agreement values from 0.58 to 0.94 for 11 stations, generally indicating agreement with the available measured data. Chlorophyll a , calibrated for seven stations, had a wider range from 0.11 to 0.74 for the index of agreement. With the current modeling framework, taste-and-odor events, related to cyanobacterial blooms, cannot be directly simulated. However, indirect estimates of cyanobacteria concentrations may be obtained by using the chlorophyll a model outputs, which represent total phytoplankton biomass, and the phytoplankton biovolume data by group (diatoms, green algae, cyanobacteria and others) collected from 2012 to 2015. For the Bushy Park Reservoir modeling framework to be used directly for taste-and-odor issues, cyanobacteria must be simulated and calibrated based on observations of cyanobacteria biomass concentrations. In addition to the cyanobacteria sampling conducted within the reservoir between 2012 and 2015, the new model calibration would also require new algae biomass data-collection efforts to characterize the external sources of cyanobacteria entering the Bushy Park Reservoir from tributaries, as well as the internal cycling, production, and decay of cyanobacteria in the hydrologic system. Further improvements to the EFDC model would include expanding the collection of boundary condition datasets, such as water-quality monitoring to determine improved nutrient loads into the model domain. Along with improved water-quality monitoring for the major boundary conditions, continuous discharge, for both Foster Creek and the Back River, would further constrain the flow balance and the loads into Bushy Park Reservoir. In addition to better boundary-condition characterization, it is important to better characterize possible shortcomings specifically to the model domain, such as the grid resolution, bathymetry, and numerical hydrodynamic errors. Further consideration of the model may involve a sensitivity analysis to determine if errors in the simulation outputs, such as discharge, water-surface elevations, and salinity, were more likely caused by poor boundary condition characterization or, specifically, the model setup. Three model scenarios were run with the revised Bushy Park Reservoir model: (1) reduced withdrawals from one of the large intake-discharge locations for Bushy Park Reservoir, the Williams Station; (2) elevated (above background levels) ocean water level causing saltwater intrusion from the ocean through Durham Canal into Bushy Park Reservoir; and (3) overtopping of the Back River Dam at the southernmost end of Bushy Park Reservoir. For the reduced withdrawals scenarios, the largest shift in flow resulted near the Williams Station intake, with the next largest flow change at the southern end of Bushy Park Reservoir, and a net increase in flow out of the Bushy Park Reservoir to the Cooper River by way of the Durham Canal. The effect resulting from scenario 3 on water quality and salinity was small, with larger increases for dissolved oxygen than other constituents at several monitoring stations. For the two scenarios related to saltwater intrusion (including dam overtopping), the changes in salinity generally were found to dissipate in the following 2 weeks and generally back to baseline salinity conditions within 3 months. This result did vary depending on the severity of the storm or length of the dam overtopping event.

South Carolina↗
USGS2009

Factors Affecting Water Quality in Domestic Wells in the Upper Floridan Aquifer, Southeastern United States, 1998-2005

The Floridan aquifer system is a highly productive carbonate aquifer that provides drinking water to about 10 million people in Florida, Georgia, and South Carolina. Approximately 1.6 million people rely on domestic wells (privately owned household wells) for drinking water. Withdrawals of water from the Floridan aquifer system have increased by more than 500 percent from 630 million gallons per day (2.38 cubic meters per day) in 1950 to 4,020 million gallons per day (15.2 cubic meters per day) in 2000, largely due to increases in population, tourism, and agriculture production. Water samples were collected from 148 domestic wells in the Upper Floridan aquifer in Florida, Georgia, South Carolina, and Alabama during 1998-2005 as part of the U.S. Geological Survey (USGS) National Water-Quality Assessment Program. The wells were located in different hydrogeologic settings based on confinement of the Upper Floridan aquifer. Five networks of wells were sampled con-sisting of 28 to 30 wells each: two networks were in unconfined areas, two networks were in semiconfined areas, and one network was in the confined area. Physical properties and concentrations of major ions, trace elements, nutrients, radon, and organic compounds (volatile organic compounds and pesticides) were measured in water samples. Concentrations were compared to water-quality benchmarks for human health, either U.S. Environmental Protection Agency (USEPA) Maximum Contaminant Levels (MCLs) for public water supplies or USGS Health-Based Screening Levels (HBSLs). The MCL for fluoride of 4 milligrams per liter (mg/L) was exceeded for two samples (about 1 percent of samples). A proposed MCL for radon of 300 picocuries per liter was exceeded in about 40 percent of samples. Nitrate concentrations in the Upper Floridan aquifer ranged from less than the laboratory reporting level of 0.06 to 8 mg/L, with a median nitrate concentration less than 0.06 mg/L (as nitrogen). Nitrate concentrations did not exceed the MCL of 10 mg/L. Statistical comparisons indicated that median nitrate concentrations were significantly different by degree of confinement where the highest median nitrate concentration was 1.46 mg/L for 58 samples from unconfined areas, and by network, where the highest median nitrate concentration was 2.43 mg/L in 28 samples from unconfined areas in southwestern Georgia. Nitrate concentrations in unconfined areas were positively correlated to: (1) the percentage of agricultural land use around the well, (2) the amount of nitrogen fertilizer applied, and (3) the dissolved oxygen concentrations in groundwater. Volatile organic compounds (VOCs) were detected in about 63 percent of all samples. Chloroform, carbon disulfide, and 1,2-dichloropropane were the most frequently detected VOCs. Chloroform, a byproduct of water chlorination, was most frequently detected in unconfined urban areas. Carbon disulfide, a solvent, was most frequently detected in confined areas in southeastern Georgia. Pesticides were detected in about 21 percent of all samples, but were detected in about 69 percent of the 28 samples from unconfined areas in southwestern Georgia. The herbicides atrazine, deethylatrazine, and metolachlor were the most frequently detected pesticides.

Scientific Investigations Report↗
USGS2010

Documentation for initial seismic hazard maps for Haiti

In response to the urgent need for earthquake-hazard information after the tragic disaster caused by the moment magnitude (M) 7.0 January 12, 2010, earthquake, we have constructed initial probabilistic seismic hazard maps for Haiti. These maps are based on the current information we have on fault slip rates and historical and instrumental seismicity. These initial maps will be revised and improved as more data become available. In the short term, more extensive logic trees will be developed to better capture the uncertainty in key parameters. In the longer term, we will incorporate new information on fault parameters and previous large earthquakes obtained from geologic fieldwork. These seismic hazard maps are important for the management of the current crisis and the development of building codes and standards for the rebuilding effort. The boundary between the Caribbean and North American Plates in the Hispaniola region is a complex zone of deformation. The highly oblique ~20 mm/yr convergence between the two plates (DeMets and others, 2000) is partitioned between subduction zones off of the northern and southeastern coasts of Hispaniola and strike-slip faults that transect the northern and southern portions of the island. There are also thrust faults within the island that reflect the compressional component of motion caused by the geometry of the plate boundary. We follow the general methodology developed for the 1996 U.S. national seismic hazard maps and also as implemented in the 2002 and 2008 updates. This procedure consists of adding the seismic hazard calculated from crustal faults, subduction zones, and spatially smoothed seismicity for shallow earthquakes and Wadati-Benioff-zone earthquakes. Each one of these source classes will be described below. The lack of information on faults in Haiti requires many assumptions to be made. These assumptions will need to be revisited and reevaluated as more fieldwork and research are accomplished. We made two sets of maps using different assumptions about site conditions. One set of maps is for a firm-rock site condition (30-m averaged shear-wave velocity, Vs30, of 760 m/s). We also developed hazard maps that contain site amplification based on a grid of Vs30 values estimated from topographic slope. These maps take into account amplification from soils. We stress that these new maps are designed to quantify the hazard for Haiti; they do not consider all the sources of earthquake hazard that affect the Dominican Republic and therefore should not be considered as complete hazard maps for eastern Hispaniola. For example, we have not included hazard from earthquakes in the Mona Passage nor from large earthquakes on the subduction zone interface north of Puerto Rico. Furthermore, they do not capture all the earthquake hazards for eastern Cuba.

Open-File Report↗
USGS2014

Reservoir controls on the occurrence and production of gas hydrates in nature

Gas hydrates in both arctic permafrost regions and deep marine settings can occur at high concentrations in sand-dominated reservoirs, which have been the focus of gas hydrate exploration and production studies in northern Alaska and Canada, and offshore in the Gulf of Mexico, off the southeastern coast of Japan, in the Ulleung Basin off the east coast of the Korean Peninsula, and along the eastern margin of India. Production testing and modeling has shown that concentrated gas hydrate occurrences in sand reservoirs are conducive to existing well-based production technologies. The resource potential of gas hydrate accumulations in sand-dominated reservoirs have been assessed for several polar terrestrial basins. In 1995, the U.S. Geological Survey (USGS) assigned an in-place resource of 16.7 trillion cubic meters of gas for hydrates in sand-dominated reservoirs on the Alaska North Slope. In a more recent assessment, the USGS indicated that there are about 2.42 trillion cubic meters of technically recoverable gas resources within concentrated, sand-dominated, gas hydrate accumulations in northern Alaska. Estimates of the amount of in-place gas in the sand dominated gas hydrate accumulations of the Mackenzie Delta Beaufort Sea region of the Canadian arctic range from 1.0 to 10 trillion cubic meters of gas. Another prospective gas hydrate resources are those of moderate-to-high concentrations within sandstone reservoirs in marine environments. In 2008, the Bureau of Ocean Energy Management estimated that the Gulf of Mexico contains about 190 trillion cubic meters of gas in highly concentrated hydrate accumulations within sand reservoirs. In 2008, the Japan Oil, Gas and Metals National Corporation reported on a resource assessment of gas hydrates in which they estimated that the volume of gas within the hydrates of the eastern Nankai Trough at about 1.1 trillion cubic meters, with about half concentrated in sand reservoirs. Because conventional production technologies favor sand-dominated gas hydrate reservoirs, sand reservoirs are considered to be the most viable economic target for gas hydrate production and will be the prime focus of most future gas hydrate exploration and development projects.

Book↗
USGS2005

Paleoproterozoic metamorphism in the northern Wyoming province: Implications for the assembly of Laurentia

U-Pb ages measured on zircons from the Tobacco Root Mountains and monazite from the Highland Mountains indicate that the northwestern Wyoming province experienced an episode of high-grade metamorphism at ???1.77 Ga. Leucosome emplaced in Archean gneisses from the Tobacco Root Mountains contains a distinctive population of zircons with an age of 1.77 Ga but also contains zircons to ???3.5 Ga; it is interpreted to have been derived primarily by anatexis of nearby Archean schist. A granulite facies mafic dike that cuts across Archean gneissic banding in the Tobacco Root Mountains contains two distinct populations of zircons. A group of small (<50 ??m) nonprismatic grains is interpreted to be metamorphic and yields an age of 1.76 Ga; a group of slightly larger prismatic grains yields an age of 2.06 Ga, which is interpreted to be the time of crystallization of the dike. Monazite from a leucogranite from the Highland Mountains yields a well-defined age of 1.77 Ga, which is interpreted as the time of partial melting and emplacement of the leucogranite. These results suggest that the northwestern Wyoming province, which largely lies within the western part of the Great Falls tectonic zone, experienced a metamorphic maximum at 1.77 Ga. This age is ???100 m.yr. younger than the proposed time of Wyoming-Hearne collision in the central Great Falls tectonic zone (1.86 Ga) and suggests that the northwestern Wyoming province may have been involved in a separate, younger collisional event at ???1.77 Ga. An event at this time is essentially coeval with collisions proposed for the eastern and southeastern margins of the province and suggests a multiepisodic model for the incorporation of the Wyoming craton into Laurentia. ?? 2005 by The University of Chicago. All rights reserved.

Journal of Geology↗
USGS1946

Copper deposits at the Rush and Brown mine and Venus prospect, Prince of Wales Island, southeastern Alaska

The Rush and Brown mine and the Venus prospect are near the head of Kasaan Bay about 10 miles northwest of the village of Kasaan and about 45 miles northwest of Ketchikan, the nearest port. (See fig. 1.) They are in an area of moderate relief in in which some hills are a little more than 500 feet high. Much of the area is covered with glacial drift and dense vegetation. Muskegs are numerous. Outcrops are scarce and are confined mostly to steep slopes, stream beds, and places where development work has been done on the ore deposits. Topographic, geologic, and magnetic surveys of the vicinities of the ore deposits were made by the Geological Survey in 1943, and a brief examination of a portion of the underground workings at the Rush and Brown mine was made in 1944. The area is underlain principally by greenstone which has been intruded by bodies of pyroxenite, gabbro, and diorite. Foliation in the greenstone is obscure. post of the intrusive bodies trend northwesterly. The principal ore deposits are veins containing chiefly pyrite, chalcopyrite, and pyrrhotite. A few deposits of copper-bearing magnetite have been found. Most of these are small, but a larger one at the Rush and Brown mine has been mined for its copper and precious metals.

Alaska↗
USGS2001

Geologic maps and cross sections of mine levels at the Pea Ridge iron mine, Washington County, Missouri

This geologic mapping and interpretation of the Pea Ridge iron mine, Missouri, is part of a cooperative effort between the U.S. Geological Survey (USGS) and the Missouri Department of Natural Resources, Division of Geology and Land Survey (DGLS), under the auspices of the USGS Midcontinent Strategic and Critical Minerals Project. The goal of the Pea Ridge study is to compare the Middle Proterozoic iron deposits of Missouri with the Middle Proterozoic Olympic Dam deposit and similar deposits of the Stuart Shelf, South Australia. This effort developed from work by Sims and others (1987), who recognized the many similarities between the St. Francois terrane in southeastern Missouri and the Stuart Shelf and also the potential for Olympic Dam-type deposits in the Middle Proterozoic granite-rhyolite terranes of the Midcontinent. Detailed descriptions of the map units are given in Nuelle and others (1992). Results of stable-isotope, fluid-inclusion, and traceelement studies that focus on the origin of the ore deposit are presented in Day and others (1991, 1992, and 1993), Sidder and others (1991, 1993a, b), and Cordell and others (1993).

Missouri↗
USGS2015

Measuring storm tide and high-water marks caused by Hurricane Sandy in New York: Chapter 2

In response to Hurricane Sandy, personnel from the U.S. Geological Survey (USGS) deployed a temporary network of storm-tide sensors from Virginia to Maine. During the storm, real-time water levels were available from tide gages and rapid-deployment gages (RDGs). After the storm, USGS scientists retrieved the storm-tide sensors and RDGs and surveyed high-water marks. These data demonstrate that the timing of peak storm surge relative to astronomical tide was extremely important in southeastern New York. For example, along the south shores of New York City and western Suffolk County, the peak storm surge of 6–9 ft generally coincided with the astronomical high tide, which resulted in substantial coastal flooding. In the Peconic Estuary and northern Nassau County, however, the peak storm surge of 9 ft and nearly 12 ft, respectively, nearly coincided with normal low tide, which helped spare these communities from more severe coastal flooding.

New York↗
USGS1989

Preparation of average annual runoff map of the United States, 1951-80

Average annual runoff was computed or estimated for 2,148 hydrologic cataloging units in the United States and Puerto Rico , for the period 1951-80. Runoff was computed from the recorded streamflow at 5,951 U.S. Geological Survey gaging stations. The runoff at more than 3,000 of these stations was estimated by correlation with other nearby stations to adjust for missing data. These runoff data were used to draw a map depicting the variation of runoff throughout the nation. Average annual runoff varied from less than 0.01 inch in parts of the Great Basin (Utah, parts of Nevada, Oregon, and California) to more than 240 inches in southeastern Alaska. (USGS)

Open-File Report↗
USGS2025

Completion summary for monitor wells NRF-17 and NRF-18 at the Naval Reactors Facility, Idaho National Laboratory, Idaho

The U.S. Geological Survey (USGS)—in cooperation with the U.S. Department of Energy (DOE) for the Naval Reactors Laboratory Field Office that supports operations for the Naval Reactors Facility (NRF) located at the Idaho National Laboratory (INL)—drilled and constructed well NRF-17 (formerly borehole USGS 151) and well NRF-18 (formerly borehole USGS 152) for stratigraphic framework analyses and water-quality monitoring at the Idaho National Laboratory (INL) near the NRF, in southeastern Idaho. Borehole USGS 151 was continuously cored from about 48 to 1,070 feet (ft) below land surface (BLS); rotary drilled from approximately 1,070 to 1,720 ft BLS; and re-drilled to complete construction as a monitor well NRF-17, completed to 461 ft BLS. Borehole USGS 152 was continuously cored from approximately 19 to 1,259 ft BLS; rotary drilled from approximately 1,259 to 1,630 ft BLS; and re-drilled to complete construction as a monitor well NRF-18, completed to 450 ft BLS. Geophysical data were examined with photographed core material to record lithologic descriptions and to suggest zones where groundwater flow was anticipated. Basalt flows varied from highly fractured to dense, with high-to-low vesiculation. Well NRF-17 generally was constructed in mostly dense basalt (greater than 75 percent), and well NRF-18 was constructed in primarily fractured and (or) vesicular basalt. In well NRF-17, the well capacity is directly affected by the limited amount of fractured basalt, which serves as the primary pathway for groundwater. This effect was observed during the pumping test conducted after the well's final construction. Single-well aquifer tests were done at wells NRF-17 and NRF-18 to provide estimates of transmissivity and hydraulic conductivity after final well construction and initial well development. Estimated values of transmissivity and hydraulic conductivity for well NRF-17 were 8.81 feet squared per day (ft 2 /d) and 1.04×10 -2 feet per day (ft/d), respectively. Estimated values of transmissivity and hydraulic conductivity for well NRF-18 were 4.77×10 3 ft 2 /d and 5.61 ft/d, respectively. The NRF-17 pump test resulted in 19.41 ft of measured drawdown at a sustained average pumping rate of 3.3 gallons per minute (gal/min). The NRF-18 pump test resulted in 0.55 ft of measured drawdown at a sustained average pumping rate of 31.0 gal/min. Water-quality samples collected from the two wells were analyzed for cations, anions, metals, nutrients, volatile organic compounds, stable isotopes, and radionuclides. Water samples for select inorganic constituents showed concentrations consistent with signatures from tributary valley groundwater with influences from ephemeral surface-water recharge from the Big Lost River. Water-quality samples analyzed for stable isotopes of oxygen and hydrogen are consistent with signatures from tributary valley groundwater and surface-water recharge inputs to the aquifer. No measured water-quality results were greater than their respective maximum contaminant levels for public drinking-water supplies. Inorganic and nutrient water-quality results for well NRF-17 and well NRF-18 suggest the groundwater in this area is potentially affected by industrial wastewater disposal.

Idaho↗
USGS1996

Hydrogeology and analysis of ground-water-flow system, Sagamore Marsh area, southeastern Massachusetts

A study of the hydrogeology and an analysis of the ground-water-flow system near Sagamore Marsh, southeastern Massachusetts, was undertaken to improve the understanding of the current (1994­ 95) hydrogeologic conditions near the marsh and how the ground-water system might respond to proposed changes in the tidal-stage regime of streams that flood and drain the marsh. Sagamore Marsh is in a coastal area that is bounded to the east by Cape Cod Bay and to the south by the Cape Cod Canal. The regional geology is characterized by deltaic and glaciolacustrine sediments. The sediments consist of gravel, sand, silt, and clay and are part of the Plymouth-Carver regional aquifer system. The glacial sediments are hounded laterally by marine sand, silt, and clay along the coast. The principal aquifer in the area consists of fine to coarse glacial sand and is locally confined by fine-grained glaciolacustrine deposits consisting of silt and sandy clay and fine-grained salt-marsh sediments consisting of peat and clay. The aquifer is underlain by finer grained glaciolacustrine sediments in upland areas and by marine clay along the coast. Shallow ground water discharges primarily along the edge of the marsh, whereas deeper ground water flows beneath the marsh and discharges to Cape Cod Bay. Tidal pulses originating from Cape Cod Bay and from tidal channels in the marsh are rapidly attenuated in the subsurface. Tidal ranges in Cape Cod Bay and in the tidal channels were on the order of 9 and 1.5 feet, respectively, whereas tidal ranges in the ground-water levels were less than 0.2 foot. Tidal pulses measured in the water table beneath a barrier beach between the marsh and Cape Cod Bay were more in phase with tidal pulses from Cape Cod Bay than with tidal pulses from the tidal channels in Sagamore Marsh, whereas tidal pulses in the regional aquifer were more in phase with tidal pulses from the tidal channels. A 5-day aquifer test at a public-supply well adjacent to the marsh gave a transmissivity of the regional aquifer of 9,300 to 10,900 feet squared per day and a hydraulic conductivity of 181 to 213 feet per day, assuming a saturated thickness of the aquifer of 51.3 feet. The regional aquifer became unconfined near the pumped well during the test. The ratio of tidal ranges in the tidal channel to the ranges in the underlying aquifer at two sites (the lower and upper marsh) indicated aquifer diffusivities for the marsh sediments of 380 and 170 feet squared per day; these values correspond to hydraulic conductivities of 2.5 x 10 -3 and 1.7 x 10 -3 feet per day, respectively. The maximum distances from the tidal channel at the lower and upper marsh sites where tidal ranges would exceed 0.01 foot, as calculated from aquifer diffusivities and current (1995) tidal ranges in the tidal channels, were 24.4 and 26.7 feet, respectively. The maximum distances from the tidal channel where tidal pulses in the ground water would exceed 0.01 foot, using potential increased tidal stages resulting from proposed tidal-stage modifications and predicted by the U.S. Army Corps of Engineers, were 37.1 and 42.0 feet, respectively. A numerical model of the marsh and surrounding aquifer system indicated that the contributing area for the supply well adjacent to the marsh, for current (1994) pumping conditions, extends toward Great Herring Pond, about 2 miles northwest (upgradient) of the well, and does not extend beneath the marsh. The model also indicates that the predicted increases in tidal stages in the marsh will have a negligible effect on local ground-water levels.

Massachusetts↗
USGS2002

Geologic map of the Eagle Quadrangle, Eagle County, Colorado

The Eagle quadrangle covers an area that straddles the Eagle River and Interstate 70 (I-70) and it includes the town of Eagle, Colo., which is located in the southwestern part of the quadrangle, just south of I-70 and the Eagle River, about 37 km west of Vail, Colo. The map area is part of the I-70 urban corridor, which is experiencing rapid and escalating urban growth. Geologic mapping along this corridor is needed for ongoing land-use planning. A variety of rocks and deposits characterize the map area and areas nearby. Sedimentary rocks present in the map area range in age from Pennsylvanian rocks, which were deposited in the ancestral Eagle basin during the formation of the ancestral Rocky Mountains, to Late Cretaceous rocks that were deposited just prior to the formation of the present Rocky Mountains. The Pennsylvanian rocks in the map area include a thick sequence of evaporitic rocks (Eagle Valley Evaporite). These evaporitic rocks are commonly complexly folded throughout the southern part of the quadrangle where they are exposed. In general, in the central and northern parts of the quadrangle, the sedimentary rocks overlying the evaporite dip gently to moderately northward. Consequently, the youngest sedimentary rocks (Late Cretaceous rocks) are exposed dipping gently to the north in the northern part of the quadrangle; landslide complexes are widespread along the northerly dipping, dip slopes in shaly rocks of the Cretaceous sequence in the northeastern part of the map area. During the Early Miocene, basaltic volcanism formed extensive basaltic flows that mantled the previously deformed and eroded sedimentary rocks. Erosional remnants of the basaltic flows are preserved in the southeastern, west-central, and north-central parts of the map area. Some of these basaltic flows are faulted and downdropped in a manner that suggests they were downdropped in areas where large volumes of the underlying evaporitic rocks were removed from the subsurface, beneath the basaltic rocks, by dissolution or flowage of the evaporite in the subsurface. Quaternary and late Tertiary(?) surficial deposits in the map area consist mainly of Quaternary alluvium and colluvium, late and middle Pleistocene terrace gravels of the Eagle River, Miocene(?) gravel remnants of the ancestral Eagle River and its tributaries, and Pleistocene to recent mass movement deposits that include landslides and debris flows. Potential geologic hazards in the map area include landslides, debris flows, rockfalls, local flooding, ground subsidence, and expansive and corrosive soils.

Colorado↗
USGS1975

Geology and water availability of Cullman County, Alabama

The Pottsville Formation of Pennsylvanian age underlies most of Cullaman County in northern Alabama. It consists mostly of interbedded sandstones and shales that dip southward about 40 feet per mile. The Bangor Limestone of Mississippian age underlies the Pottsville and crops out in a few valleys along the northern boundary of the county. The principal source of ground water in the county is the Pottsville Formation. Sandstones of the Pottsville Formation underlying low topographic areas will yield as Much as 200 gpm (gallons per minute) to individual wells 200 feet deep or less in the southeastern part of the the county and 25-100 gpm in other parts. Those underlying high topographic areas generally yield less than 5 gpm. The average flow of streams in and adjoining Cullman County is about 1,500 mgd (million gallons per day) which includes about 780 mgd that originates in the county. Discharge from ground-water storage is small, and most streams cease to flow during extended dry periods. Sipsey Fork and Mulberry Fork are the only streams in and adjoining Cullman County that have median annual 7-day low flows that exceed 2 mgd.

Alabama↗
USGS1996

Diatom constraints on the position of the Antarctic Polar Front in the middle part of the Pliocene

The relative percentages of diatom taxa in 5 deep-sea cores (DSDP 266, ODP 699A, ODP 747A, ODP 751 A, and Eltanin Core 50-28) from the Southern Ocean are determined for an interval centered on 3.1 to 2.9 Ma in the middle part of the Pliocene. This climatically warm interval, which is being studied by the PRISM Project of the U.S. Geological Survey, coincides with a proposed interval of major deglaciation of East Antarctica. The maximum southerly position of the Antarctic Polar Front between 3.1 and 3.0 Ma is inferred from these diatom studies, the presence of calcareous nannofossils in the sediments, and sedimentologic and micropaleontologic information from the literature. It is suggested that the Antarctic Polar Front may have migrated by as much as 6 ° of latitude further to the south in the southeastern Atlantic and Indian Oceans during this Pliocene warm interval but probably lay close to its present day position in the southwest Atlantic and Drake Passage. Summer sea surface temperatures are inferred to have been no more than 3 °–4 °C warmer than present at latitudes between 55 ° and 60 °S.

Marine Micropaleontology↗
USGS2001

Geologic Maps of the Dardanus Sulcus (Jg-6), Misharu (Jg-10), Nabu (Jg-11), and Namtar (Jg-14) Quadrangles of Ganymede

Ganymede is the largest (~5,200 km diameter) of the Jovian satellites. Surficial features on Ganymede, as recorded by the Voyager 1 and 2 spacecraft (Smith and others, 1979a; 1979b), indicate a complex history of crustal formation. Several episodes of crustal modification led to the formation of curvilinear systems of furrows in dark terrain, the emplacement of light materials, and the creation of grooves in light terrain. Prior to exploration of the Jovian system by spacecraft, Earth-based observations established that the surface of Ganymede is dominated by water ice with various admixtures of fine silicate (rock) material (Pilcher and others, 1972; Sill and Clark, 1982). No agreement yet exists as to the amount of water in the near surface material; early estimates based on spectral reflectance data suggested that half the surface was covered by nearly pure water ice, whereas later studies by Clark (1981) indicated that up to 95% of the surface could be water ice and still be consistent with spectroscopic data. The Pioneer encounters with the Jovian system in 1973 and 1974 confirmed that Ganymede was made up of patches of light and dark terrain but did not have the spatial resolution needed to determine the percent cover of water ice, or geologic relations of surface materials. Not until the Voyager encounters was the surface seen with sufficient detail to enable geologic mapping. On the basis of albedo contrasts, surface morphology, crater density, and superposition relations, geologic mapping was done using principles and techniques that have been applied to the Earth, Moon, and other terrestrial planets (Wilhelms, 1972). Considerable uncertainty exists in applying such methods to bodies having icy crusts, as the internal processes that produce their surface configurations are poorly understood, and the resolution of the Voyager images is barely sufficient to show the detail required to interpret structural and stratigraphic relations. With the exception of the extreme southeastern portion of the Namtar quadrangle (Jg- 14), all images used for mapping were taken by Voyager 1. At the time of encounter, the eastern portion of the Misharu (Jg–10) and Namtar quadrangles were near the terminator, making it difficult to distinguish albedo variations best seen at high sun angles. The western quadrangles were imaged at resolutions of 2–5 km/pixel (Batson and others, 1980) from an oblique angle, so albedo variations can be seen, but topography and morphology are not well expressed in the images.

IMAP↗