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At least 613 records · Page 34Linked to original sources
USGS1981

Surface-water resources in the Tooele 2° quadrangle, Utah

This is one of a series of maps that describe the geology and related natural resources of the Tooele 2° quadrangle. The purpose of this map is to describe on a regional scale the availability and chemical quality of surface water and to guide readers to more detailed site-specific information about the resource in this generally semiarid region. Most of the data used to compile this map were collected by the U.S. Geological Survey under cooperative programs with the Utah Departments of Natural Resources and Transportation. Those data are available in the files of the U.S. Geological Survey, Water Resources Division, Salt Lake City, Utah.

Utah↗
USGS1981

Map showing mineral-resource potential of the King Range and Chemise Mountain Instant Study Areas, Humboldt and Mendocino counties, California

The potential for economic development of energy-related or metallic mineral resources in the King Range and Chemise Mountain Instant Study Areas is low to moderate as indicated by geologic, geophysical, and geochemical investigations. No oil or gas seeps or coal seams were detected within the King Range or Chemise Mountain Study Area. The low porosity and permeability of the Franciscan sandstones that underlie these areas indicate a very low potential for oil or gas. The geothermal resource potential of these areas also is low. Minor manganese resources occur adjacent to the southeast corner of the King Range Instant Study Area near Queen Peak. The manganese forms small stratabound deposits associated with radiolarian chert and pillow basalt. The known deposits are too small and the manganese too low in concentration for further economic exploitation. Similar manganese mineralization may be within the belt of melange in the southeast corner of the King Range area and within the Chemise Mountain Instant Study Area, but economic deposits are unlikely. Although there has been historical base- and precious-metal exploration activity north of the King Range in the Mattole River drainage, our geologic and geochemical field data indicate almost no gold potential and low potentials for lead, zinc, copper, and silver. During this investigation, one high-grade vein and several minor veins containing lead, zinc, copper, and silver were discovered at Point Delgada immediately south of the King Range Instant Study Area. The vein mineralization is Miocene and cuts Cretaceous basalt flows, dikes, flow breccia, and younger overlying sedimentary rocks of the King Range. The vein mineralization at Point Delgada could be remobilized from more extensive unexposed stratabound base-metal mineralization at depth. Traces of lead and zinc detected within the King Range Instant Study Area may have similar stratabound or vein origins, but no resource potential is indicated. Minor copper mineralization with associated lead, zinc, and manganese anomalies within the Chemise Mountain Instant Study Area is of low economic potential because of the shearing, isolation, and lenticularity of the basaltic and cherty rocks within the melange mineralization.

California↗
USGS1980

Maps showing coal resources of the Crumpler quadrangle, Mercer, McDowell, and Wyoming Counties, West Virginia

Coal Geology The Crumpler quadrangle lies in the Appalachian Plateaus province, with the coal bearing Pocahontas and New River Formations of Pennsylvanian age having a gentle dip toward the northwest. Coal bed maps were prepared (figures 1-7) and resources were estimated (table 1) for seven of the many coal beds in the Crumpler quadrangle (Stricker, 1980, lists the names of the various coal beds in the quadrangle) following methods established by U.S. Bureau of Mines and U.S. Geological Survey, 1976. All of these coal beds crop out at the surface in the quadrangle, have a maximum thickness thickness of over-burden of less than 300 meters, and have been mined at the surface, or under-ground, or both. Resource estimates were not calculated for other coal beds in the Pocahontas and New River Formations, either because of insufficient data of because of the beds are too thin. Figure 8 is a generalized stratigraphic column of the coal-bearing sequence in the Crumpler quadrangle showing thickness and relative positions of the various coal beds. The Crumpler quadrangle originally contained about 498 million metric tons of coal. Approximately 326 million metric tons have been mined, or lost in mining, leaving remaining resources of 172 million metric tons. Analyses of the mined coal beds in the Crumpler and adjacent quadrangle show the coal is medium - to low volatile bituminous (most are low volatile bituminous), containing 14-27 percent volatile matter (with an arithmetic mean of 18 percent), 2.1-22.4 percent ash (with an arithmetic mean of 7 percent), and 0.5-1.8 percent total sulfur (with an arithmetic mean of 0.8 percent). Heating values range from 6,380 to 8,610 Kcal/kg on an as-received basis. Trace element and major and minor oxide composition, of both whole coal and laboratory ash, for 59 samples within or near the quadrangle were obtained from USCHEM (Geochemical Data File or National Coal Resources Data System), (Kozey and others, 1980.) Neither elements of environmental concern such as arsenic, lead, mercury, and selenium nor potentially valuable elements such as germanium, uranium and thorium were found in significant amounts in the coal.

West Virginia↗
USGS1983

Mineral resource potential map of the Stansbury Roadless Area, Tooele County, Utah

The U.S. Bureau of Mines and the U.S. Geological Survey have conducted a survey to determine the mineral resource potential of the eastern part (D4757) of the Stansbury Roadless Area, Tooele County, Utah. The results of this survey indicate that a low to moderate potential for copper, lead, and silver mineralization exists in part of area D4757. The balance of area D4757 is considered to have a low potential for metallic mineralization. The oil and gas potential is not known and cannot be assessed without a program of geophysical exploration and exploratory drilling. Limestone and dolomite are exposed over a large part of the roadless area, forming a major industrial mineral resource, but an extensive sampling and testing program is needed to determine the degree of purity of the rocks and, hence, the value of the resource. There are no known geothermal resources within the study area.

Utah↗
USGS1983

Mineral resource potential map of the Great Rift Instant Study Area, Blaine, Butte, Minidoka, and Power counties, Idaho

A high potential exists for development of decorative building stone resources from slabby, glassy-surfaced pahoehoe lava flows, particularly in the Wapi lava field where the largest volume and variety of stone occurs. The unique appearance of the Blue Dragon flow material from the Craters of the Moon lava field may enhance its potential as a decorative stone resource. Locating speculative resources (uraniferous sediment, auriferous gravel, and geothermal reservoirs) and hypothetical resources (oil and gas) that may underlie the geologically young lava flows of the study area would require extensive geophysical exploration and drilling.

Idaho↗
USGS1993

Mineral resource assessment of rare-earth elements, thorium, titanium, and uranium in the Greenville 1° x 2° quadrangle, South Carolina, Georgia, and North Carolina

Mineral resources of the Greenville 1° x 2° quadrangle, South Carolina, Georgia, and North Carolina, were assessed between 1984 and 1990 under the Conterminuous United States Mineral Assessment Program (CUSMAP) of the U.S. Geological Survey (USGS). The mineral resource assessments were made on the basis of geologic, geochemical, and geophysical investigations and the presence of mines, prospects, and mineral occurrences from the literature. This report is an assessment of the rare-earth elements (REE), thorium, titanium, and uranium resources in the Greenville quadrangle and is based on heavy mineral concentrates collected in 1951-54 by the USGS (Overstreet and others, 1968; Caldwell and White, 1973; Cuppels and White, 1973); on the results of the U.S. Department of Energy, National Uranium Resource Evaluation (NURE) sampling program (Ferguson, 1978, 1979); on analyses of stream-sediment and heavy-mineral-concentrate samples (Jackson and Moore, 1992, G.C Cullin, USGS, unpub. data, 1992) on maps showing aerial gamma radiation in the Greenville quadrangle (D.L. Daniels, USGS, unpub. data, 1992); and on the geology as mapped by Nelson and others (1987, 1989).

Georgia, North Carolina, South Carolina↗
USGS2000

Assessment of mineral resource tracts in the Chugach National Forest, Alaska

Locatable minerals have been produced from the Chugach National Forest (CNF) for nearly 100 years. Past gold production has come from the Kenai Peninsula and the Girdwood, Port Wells, and Valdez areas. Copper and by-product gold and silver have been produced from mines at Ellamar, on Latouche Island, and near Valdez. Many of the past-producing properties were not mined out and contain significant inferred reserves of gold, copper, lead, zinc, and silver. This report outlines mineral resource areas (tracts) that contain both identified and undiscovered mineral resources. These tracts were drawn on the basis of one or more of the following criteria: (1) geochemical anomalies, (2) favorable geologic units, (3) presence of mines, prospects or mineral occurrences, and (4) geophysical anomalies. Bliss (1989) used six mineral deposit models to describe the types of deposits known from the CNF. Of these deposit types, only four are sufficiently known and defined in the CNF to be suitable for consideration in outlining and ranking of mineral resource tracts; these deposit types are: (1) Cyprus-type massive sulfide, (2) Chugach-type low-sulfide goldquartz veins, (3) placer gold, and (4) polymetallic vein. The U.S. Bureau of Mines indicated that most of the inferred mineral reserves in the CNF would not be economic to produce under current prices. Small-scale placer gold operations are a possible exception. Other known resources that have recorded past production (oil, coal, rock, sand, and gravel) are not addressed in this report.

Alaska↗
USGS2003

NOGA Online: a USGS resource for energy GIS data and services

The PowerPoint presentation in this report was given at the BLM Resource Management Tools Conference in Phoenix, Arizona, April, 2003. Some diagrams that appeared in the original presentation have been updated in this report. It informs that the U.S. Geological Survey (USGS) Central Energy Resources Team (CERT) in Denver, Colorado, is providing National Oil and Gas Assessment (NOGA) results online at http://energy.cr.usgs.gov/oilgas/noga/. Available at this site are recently completed assessments of the potential for undiscovered oil and natural gas resources of five priority provinces (Montana Thrust Belt, Powder River Basin, San Juan Basin, Southwestern Wyoming, Uinta-Piceance) to meet the requirements of the Energy Policy and Conservation Act of 2000 (EPCA 2000). High demand for current assessment results and for the entirely digital, 1995 NOGA results for other provinces, prompted CERT to develop an internet map application using ArcIMS to deliver geologic data to the public. CERT continues to work on assessing oil and natural gas resources of priority basins in the United States; assessment results and GIS layers are made available at this site on an ongoing basis.

Open-File Report↗
USGS2000

Analytical results and sample locality map for rock, stream-sediment, and soil samples, Northern and Eastern Colorado Desert BLM Resource Area, Imperial, Riverside, and San Bernardino Counties, California

In 1996-1998 the U.S. Geological Survey (USGS) conducted a geochemical study of the Bureau of Land Management's (BLM) 5.5 million-acre Northern and Eastern Colorado Desert Resource Area (usually referred to as the NECD in this report), Imperial, Riverside, and San Bernardino Counties, southeastern California (figure 1). This study was done in support of the BLM's Coordinated Management Plan for the area. This report presents analytical data from this study. To provide comprehensive coverage of the NECD, we compiled and examined all available geochemical data, in digital form, from previous studies in the area, and made sample-site plots to aid in determining where sample-site coverage and analyses were sufficient, which samples should be re-analyzed, and where additional sampling was needed. Previous investigations conducted in parts of the current study area included the National Uranium Resource Evaluation (NURE) program studies of the Needles and Salton Sea 1° x 2° quadrangles; USGS studies of 12 BLM Wilderness Study Areas (WSAs) (Big Maria Mountains, Chemehuevi Mountains, Chuckwalla Mountains, Coxcomb Mountains, Mecca Hills, Orocopia Mountains, Palen-McCoy, Picacho Peak, Riverside Mountains, Sheephole Valley (also known as Sheep Hole/Cadiz), Turtle Mountains, and Whipple Mountains); and USGS studies in the Needles and El Centro 1° x 2° quadrangles done during the early 1990s as part of a project to identify the regional geochemistry of southern California. Areas where we did new sampling of rocks and stream sediments are mainly in the Chocolate Mountain Aerial Gunnery Range and in Joshua Tree National Park, which extends into the west-central part of the NECD, as shown in figure 1 and figure 2. This report contains analytical data for 132 rock samples and 1,245 stream-sediment samples collected by the USGS, and 362 stream-sediment samples and 189 soil samples collected during the NURE program. All samples are from the Northern and Eastern Colorado Desert BLM Resource Area and vicinity. Included in the 1,245 stream-sediment samples collected by the USGS are 284 samples collected as part of the current study, 817 samples collected as part of investigations of the12 BLM WSAs and re-analyzed for the present study, 45 samples from the Needles 1° x 2° quadrangle, and 99 samples from the El Centro 1° x 2° quadrangle. The NURE stream-sediment and soil samples were re-analyzed as part of the USGS study in the Needles quadrangle. Analytical data for samples from the Chocolate Mountain Aerial Gunnery Range, which is located within the area of the NECD, were previously reported (King and Chaffee, 1999a). For completeness, these results are also included in this report. Analytical data for samples from the area of Joshua Tree National Park that is within the NECD have also been reported (King and Chaffee, 1999b). These results are not included in this report. The analytical data presented here can be used for baseline geochemical, mineral resource, and environmental geochemical studies.

California↗
USGS2012

Version 3.0 of EMINERS - Economic Mineral Resource Simulator

Quantitative mineral resource assessment, as developed by the U.S. Geological Survey (USGS), consists of three parts: (1) development of grade and tonnage mineral deposit models; (2) delineation of tracts permissive for each deposit type; and (3) probabilistic estimation of the numbers of undiscovered deposits for each deposit type. The estimate of the number of undiscovered deposits at different levels of probability is the input to the EMINERS (Economic Mineral Resource Simulator) program. EMINERS uses a Monte Carlo statistical process to combine probabilistic estimates of undiscovered mineral deposits with models of mineral deposit grade and tonnage to estimate mineral resources. Version 3.0 of the EMINERS program is available as this USGS Open-File Report 2004-1344. Changes from version 2.0 include updating 87 grade and tonnage models, designing new templates to produce graphs showing cumulative distribution and summary tables, and disabling economic filters. The economic filters were disabled because embedded data for costs of labor and materials, mining techniques, and beneficiation methods are out of date. However, the cost algorithms used in the disabled economic filters are still in the program and available for reference for mining methods and milling techniques. The release notes included with this report give more details on changes in EMINERS over the years. EMINERS is written in C++ and depends upon the Microsoft Visual C++ 6.0 programming environment. The code depends heavily on the use of Microsoft Foundation Classes (MFC) for implementation of the Windows interface. The program works only on Microsoft Windows XP or newer personal computers. It does not work on Macintosh computers. For help in using the program in this report, see the "Quick-Start Guide for Version 3.0 of EMINERS-Economic Mineral Resource Simulator" (W.J. Bawiec and G.T. Spanski, 2012, USGS Open-File Report 2009-1057, linked at right). It demonstrates how to execute EMINERS software using default settings and existing deposit models.

Open-File Report↗
USGS2006

Response to memorandum by Rowley and Dixon regarding U.S. Geological Survey report titled "Characterization of Surface-Water Resources in the Great Basin National Park Area and Their Susceptibility to Ground-Water Withdrawals in Adjacent Valleys, White Pine County, Nevada"

Applications pending for permanent permits to pump large quantities of ground water in Spring and Snake Valleys adjacent to Great Basin National Park (the Park) prompted the National Park Service to request a study by the U.S. Geological Survey to evaluate the susceptibility of the Park's surface-water resources to pumping. The result of this study was published as U.S. Geological Survey Scientific Investigations Report 2006-5099 'Characterization of Surface-Water Resources in the Great Basin National Park Area and Their Susceptibility to Ground-Water Withdrawals in Adjacent Valleys, White Pine County, Nevada,' by P.E. Elliott, D.A. Beck, and D.E. Prudic. That report identified areas within the Park where surface-water resources are susceptible to ground-water pumping; results from the study showed that three streams and several springs near the eastern edge of the Park were susceptible. However, most of the Park's surface-water resources likely would not be affected by pumping because of either low-permeability rocks or because ground water is sufficiently deep as to not be directly in contact with the streambeds. A memorandum sent by Peter D. Rowley and Gary L. Dixon, Consulting Geologists, to the Southern Nevada Water Authority (SNWA) on June 29, 2006 was critical of the report. The memorandum by Rowley and Dixon was made available to the National Park Service, the U.S. Geological Survey, and the public during the Nevada State Engineer's 'Evidentiary Exchange' process for the recent hearing on applications for ground-water permits by SNWA in Spring Valley adjacent to Great Basin National Park. The U.S. Geological Survey was asked by the National Park Service to assess the validity of the concerns and comments contained in the Rowley and Dixon memorandum. An Administrative Letter Report responding to Rowley and Dixon's concerns and comments was released to the National Park Service on October 30, 2006. The National Park Service subsequently requested that the contents with three minor changes to the Administrative Letter Report be released to the public. The first paragraph was revised to better explain how the memorandum was brought to the attention of the National Park Service and the U.S. Geological Survey and the purpose of the Administrative Letter Report. The second and third changes were minor word changes to the end of the first sentence at the top of page 11 and in the Summary statement, respectively. The Administrative Letter Report with these minor changes is reproduced herein. Lastly, the National Park Service asked me to explain the difference between potentially and likely susceptible areas used in the report. Admittedly, the report did not clearly explain their usage. Potentially susceptible areas were used in the report to identify areas where (1) ground water interacts with water in the creeks but the connection between permeable rocks in the mountains with the basin fill is uncertain or where (2) ground-water interaction with water in the creeks is less certain but permeable rocks are connected with basin fill. Likely susceptible areas were used to identify areas in the mountains and valleys where ground-water interacts with water in the creeks or discharges as springs and permeable rocks are connected with basin fill. Likely susceptible areas are, therefore, more vulnerable to ground-water pumping.

Open-File Report↗
USGS2008

Mapping of Florida's coastal and marine resources: Setting priorities workshop

The importance of mapping habitats and bioregions as a means to improve resource management has become increasingly clear. Large areas of the waters surrounding Florida are unmapped or incompletely mapped, possibly hindering proper management and good decisionmaking. Mapping of these ecosystems is among the top priorities identified by the Florida Oceans and Coastal Council in their Annual Science Research Plan. However, lack of prioritization among the coastal and marine areas and lack of coordination of agency efforts impede efficient, cost–effective mapping. A workshop on Mapping of Florida’s Coastal and Marine Resources was sponsored by the U.S. Geological Survey (USGS), Florida Department of Environmental Protection (FDEP), and Southeastern Regional Partnership for Planning and Sustainability (SERPPAS). The workshop was held at the USGS Florida Integrated Science Center (FISC) in St. Petersburg, FL, on February 7-8, 2007. The workshop was designed to provide State, Federal, university, and non-governmental organizations (NGOs) the opportunity to discuss their existing data coverage and create a prioritization of areas for new mapping data in Florida. Specific goals of the workshop were multifold, including to: provide information to agencies on state-of-the-art technology for collecting data; inform participants of the ongoing mapping programs in waters off Florida; present the mapping needs and priorities of the State and Federal agencies and entities operating in Florida; work with State of Florida agencies to establish an overall priority for areas needing mapping; initiate discussion of a unified classification of habitat and bioregions; discuss and examine the need to standardize terminology and data collection/storage so that data, in particular habitat data, can be shared; identify opportunities for partnering and leveraging mapping efforts among agencies and entities; identify impediments and organizational gaps that hinder collection of data for mapping; seek innovative solutions to the primary obstacles identified; identify the steps needed to move mapping of Florida’s oceans and coasts forward, in preparation for a better coordinated, more cost-effective mapping program to allow State and Federal agencies to make better decisions on coastal-resource issues. Over 90 invited participants representing more than 30 State and Federal agencies, universities, NGOs, and private industries played a large role in the success of this two-day workshop. State of Florida agency participants created a ranked priority order for mapping 13 different regions around Florida. The data needed for each of the 13 priority regions were outlined. A matrix considering State and Federal priorities was created, utilizing input from all agencies. The matrix showed overlapping interests of the entities and will allow for partnering and leveraging of resources. The five most basic mapping needs were determined to be bathymetry, high-vertical resolution coastline for sea-level rise scenarios, shoreline change, subsurface geology, and benthic habitats at sufficient scale. There was a clear convergence on the need to coordinate mapping activities around the state. Suggestions for coordination included: creating a glossary of terms: a standard for specifying agency data-mapping needs; creating a geographic information officer (GIO) position or permanent organizing group to maintain communications established at this workshop and to maintain progress on the issues identified during the workshop. The person or group could develop a website, maintain a project-status matrix, develop a list of contacts, create links to legislative updates and links to funding sources; developing a web portal and one-stop/clearinghouse of data. There was general consensus on the need to adopt a single habitat classification system and a strategy to accommodate existing systems smoothly. Unresolved aspects of the systems warrant that a separate workshop would be needed to work out details. Participants recognized that the State priority list would necessarily be updated periodically. An annual review of priorities would facilitate information exchange, mapping activities updates, and re-allocation of funding among changing priorities. It was recognized that mapping of State waters would take billions of dollars and in light of tightening budgets there was need for processes that could be used to appropriate or leverage monies for mapping and reduce data-collection costs. Fourteen different avenues were explored. There was a clear consensus that the linking of public to private partnerships to support mapping was imperative, and ways to achieve this were discussed.

Florida↗
USGS2008

Geologic resource evaluation of Pu'uhonua O Honaunau National Historical Park, Hawai'i; Part I, geology and coastal landforms

Geologic resource inventories of lands managed by the National Park Service (NPS) are important products for the parks and are designed to provide scientific information to better manage park resources. Park-specific geologic reports are used to identify geologic features and processes that are relevant to park ecosystems, evaluate the impact of human activities on geologic features and processes, identify geologic research and monitoring needs, and enhance opportunities for education and interpretation. These geologic reports are planned to provide a brief geologic history of the park and address specific geologic issues forming a link between the park geology and the resource manager. The Kona coast National Parks of the Island of Hawai'i are intended to preserve the natural beauty of the Kona coast and protect significant ancient structures and artifacts of the native Hawaiians. Pu'ukohola Heiau National Historic Site (PUHE), Kaloko-Honokohau National Historical Park (KAHO), and Pu'uhonua O Honaunau National Historical Park (PUHO) are three Kona parks studied by the U.S. Geological Survey (USGS) Coastal and Marine Geology Team in cooperation with the National Park Service. This report is one of six related reports designed to provide geologic and benthic-habitat information for the three Kona parks. Each geology and coastal-landform report describes the regional geologic setting of the Hawaiian Islands, gives a general description of the geology of the Kona coast, and presents the geologic setting and issues for one of the parks. The related benthic-habitat mapping reports discuss the marine data and habitat classification scheme, and present results of the mapping program. Pu'uhonua O Honaunau National Historical Park ('Place of Refuge of Honaunau') is the southernmost of the three National Parks located on the leeward Kona coast of the Island of Hawai'i. It is a relatively small park originally 73 ha (182 acres), and was expanded in 2006 with the acquisition of an additional 96 ha (238 acres). The park is probably best known for the pu'uhonua (place of refuge) native Hawaiian cultural site. In addition to the pu'uhonua, the park contains palace grounds, royal fishponds, burial sites, prehistoric trails, a royal canoe landing area, stone house platforms and associated temple structures. A massive basalt rock wall (300 m long, 3 m high, and 5 m wide) separates the pu'uhonua from the areas used by Hawaiian royalty and other grounds. Honaunau Bay is a popular marine resource area adjacent to the park. The seaward-sloping lands of PUHO lie at the base of Mauna Loa volcano, which forms a bench of low-lying pahoehoe lava flows at Pu'uhonua Point. The park coastline is approximately 1.6 km long and is mostly rocky with the exception of a small artificially nourished beach at Keone'ele Cove at the northern boundary next to Honaunau Bay. The park is bounded to the south by Ki'ilae Bay and includes the coastal portions of three Hawaiian land divisions (ahupua'a): Honaunau, Keokea, and Ki'ilae. The western boundary is the high tide mark. The waters of Keone'ele Cove, the ancient royal canoe landing at PUHO, while not formally under NPS jurisdiction, are managed by the park under an agreement with the State of Hawai'i. This small embayment is a known haven for sea turtles, which are often found sunning themselves on the nearshore volcanic platform. Impacts to this area include frequent visits by scuba divers and snorkelers to Honaunau Bay and a small boat ramp located just to the north of Keone'ele Cove. There is an accompanying report that presents the results of benthic habitat mapping of the offshore waters for PUHO (Cochran and others, 2006b; linked below). They mapped from the shoreline to depths of approximately 40 m, where the shelf drops off to a sand-covered bottom. PUHO park boundaries extend only to the mean high-tide level; however, landscape impacts created by development around the park are of concern to

Hawaii↗
USGS2008

Quantitative mineral resource assessment of copper, molybdenum, gold, and silver in undiscovered porphyry copper deposits in the Andes Mountains of South America

Quantitative information on the general locations and amounts of undiscovered porphyry copper resources of the world is important to exploration managers, land-use and environmental planners, economists, and policy makers. This publication contains the results of probabilistic estimates of the amounts of copper (Cu), molybdenum (Mo), gold (Au), and silver (Ag) in undiscovered porphyry copper deposits in the Andes Mountains of South America. The methodology used to make these estimates is called the 'Three-Part Form'. It was developed to explicitly express estimates of undiscovered resources and associated uncertainty in a form that allows economic analysis and is useful to decisionmakers. The three-part form of assessment includes: (1) delineation of tracts of land where the geology is permissive for porphyry copper deposits to form; (2) selection of grade and tonnage models appropriate for estimating grades and tonnages of the undiscovered porphyry copper deposits in each tract; and (3) estimation of the number of undiscovered porphyry copper deposits in each tract consistent with the grade and tonnage model. A Monte Carlo simulation computer program (EMINERS) was used to combine the probability distributions of the estimated number of undiscovered deposits, the grades, and the tonnages of the selected model to obtain the probability distributions for undiscovered metals in each tract. These distributions of grades and tonnages then can be used to conduct economic evaluations of undiscovered resources in a format usable by decisionmakers. Economic evaluations are not part of this report. The results of this assessment are presented in two principal parts. The first part identifies 26 regional tracts of land where the geology is permissive for the occurrence of undiscovered porphyry copper deposits of Phanerozoic age to a depth of 1 km below the Earth's surface. These tracts are believed to contain most of South America's undiscovered resources of copper. The second part presents probabilistic estimates of the amounts of copper, molybdenum, gold, and silver in undiscovered porphyry copper deposits in each tract. The study also provides tables showing the location, tract number, and age (if available) of discovered deposits and prospects. For each of the 26 permissive tracts delineated in this study, summary information is provided on: (1) the rationale for delineating the tract; (2) the rationale for choosing the mineral deposit model used to assess the tract; (3) discovered deposits and prospects; (4) exploration history; and (5) the distribution of undiscovered deposits in the tract. The scale used to evaluate geologic information and draw tracts is 1:1,000,000.

Open-File Report↗
USGS2010

Basal Resources in Backwaters of the Colorado River Below Glen Canyon Dam-Effects of Discharge Regimes and Comparison with Mainstem Depositional Environments

Eight species of fish were native to the Colorado River before the closure of Glen Canyon Dam, but only four of these native species are currently present. A variety of factors are responsible for the loss of native fish species and the limited distribution and abundance of those that remain. These factors include cold and constant water temperatures, predation and competition with nonnative fish species, and food limitation. Backwaters are areas of stagnant flow in a return-current channel and are thought to be critical rearing habitat for juvenile native fish. Backwaters can be warmer than the main channel and may support higher rates of food production. Glen Canyon Dam is a peaking hydropower facility and, as a result, has subdaily variation in discharge because of changes in demand for power. Stable daily discharges may improve the quality of nearshore rearing habitats such as backwaters by increasing warming, stabilizing the substrate, and increasing food production. To evaluate whether backwaters have greater available food resources than main-channel habitats, and how resource availability in backwaters is affected by stable flow regimes, we quantified water-column and benthic food resources in backwaters seasonally for 1 year using both standing (organic matter concentration/density; chlorophyll a concentration/density; zooplankton concentration; benthic invertebrate density and biomass) and process measurements (chamber estimates of ecosystem metabolism). We compared backwater resource measurements with comparable data from main-channel habitats, and compared backwater data collected during stable discharge with data collected when there was subdaily variation in discharge. Rates of primary production in backwaters (mean gross primary production of 1.7 g O2/m2/d) and the main channel (mean gross primary production of 2.0 g O2/m2/d) were similar. Benthic organic matter standing stock (presented as ash-free dry mass-AFDM) was seven times higher in backwaters relative to main-channel habitats (median value of 210 g AFDM/m2 versus 27 g AFDM/m2); this likely reflects greater retention of tributary-derived organic matter in backwaters relative to main-channel habitats. Water-column and benthic organic matter were higher during periods of steady discharge relative to periods of fluctuating discharge. However, our steady-discharge data collection was confounded by tributary activity. Flooding tributaries contribute substantial quantities of sediment and organic matter to the Colorado River; there were two large tributary floods during our steady-discharge data collection but none during our fluctuating-discharge data collections. Although only preliminary data on invertebrate biomass are available at this time, invertebrate biomass in backwaters (range 2-27 mg AFDM/m2) appears low relative to previously published data from main-channel habitats (~100 mg AFDM/m2). The rate of water turnover in backwaters may be a master variable that affects both physical (for example, warming) and biological (for example, primary production) processes in backwaters. We used dye tracer studies to estimate turnover rates in backwaters across flow regimes. Turnover took considerably longer when discharge was stable compared to when there was subdaily variation in discharge (613 minutes versus 220 minutes). Our results indicate that backwaters may represent a sink for organic matter that enters from the main channel and that stable discharge, by lengthening water turnover times, will likely increase organic matter retention.

Open-File Report↗
USGS2011

Usage and administration manual for a geodatabase compendium of water-resources data: Rio Grande Basin from the Rio Arriba-Sandoval County line, New Mexico, to Presidio, Texas, 1889-2009

The U.S. Geological Survey, in cooperation with the New Mexico Interstate Stream Commission, developed a geodatabase compendium (hereinafter referred to as the 'geodatabase') of available water-resources data for the reach of the Rio Grande from Rio Arriba-Sandoval County line, New Mexico, to Presidio, Texas. Since 1889, a wealth of water-resources data has been collected in the Rio Grande Basin from Rio Arriba-Sandoval County line, New Mexico, to Presidio, Texas, for a variety of purposes. Collecting agencies, researchers, and organizations have included the U.S. Geological Survey, Bureau of Reclamation, International Boundary and Water Commission, State agencies, irrigation districts, municipal water utilities, universities, and other entities. About 1,750 data records were recently (2010) evaluated to enhance their usability by compiling them into a single geospatial relational database (geodatabase). This report is intended as a user's manual and administration guide for the geodatabase. All data available, including water quality, water level, and discharge data (both instantaneous and daily) from January 1, 1889, through December 17, 2009, were compiled for the study area. A flexible and efficient geodatabase design was used, enhancing the ability of the geodatabase to handle data from diverse sources and helping to ensure sustainability of the geodatabase with long-term maintenance. Geodatabase tables include daily data values, site locations and information, sample event information, and parameters, as well as data sources and collecting agencies. The end products of this effort are a comprehensive water-resources geodatabase that enables the visualization of primary sampling sites for surface discharges, groundwater elevations, and water-quality and associated data for the study area. In addition, repeatable data processing scripts, Structured Query Language queries for loading prepared data sources, and a detailed process for refreshing all data in the compendium have been developed. The geodatabase functionality allows users to explore spatial characteristics of the data, conduct spatial analyses, and pose questions to the geodatabase in the form of queries. Users can also customize and extend the geodatabase, combine it with other databases, or use the geodatabase design for other water-resources applications.

New Mexico, Texas↗
USGS2011

Aggregate resource availability in the conterminous United States, including suggestions for addressing shortages, quality, and environmental concerns

One-third of America's major roads are in poor or mediocre condition, and over one-quarter of the bridges are either structurally deficient or functionally obsolete. A 70-percent increase in annual aggregate production may be required to upgrade the transportation infrastructure. Natural aggregate is widespread throughout the conterminous United States, but the location of aggregate is determined by geology and is non-negotiable. Natural aggregate is in short supply in the Coastal Plain and Mississippi embayment, Colorado Plateau and Wyoming Basin, glaciated Midwest, High Plains, and the non-glaciated Northern Plains. A variety of techniques have been used to overcome local shortages, such as the use of substitute materials, recycling, and importing high-quality aggregates from more distant locations. Although potential sources of aggregate are widespread throughout the United States, many sources may not meet certain physical property requirements, such as soundness, hardness, strength, porosity, and specific gravity, or they may contain contaminants or deleterious materials that render them unusable. Encroachment by conflicting land uses, permitting considerations, environmental issues, and societal pressures can prevent or limit development of otherwise suitable aggregate. The use of sustainable aggregate resource management can help ensure an economically viable supply of aggregate. Sustainable aggregate resource management techniques that have successfully been used include (1) protecting potential resources from encroachment; (2) using marginal-quality local aggregate for applications that do not demand a high-quality resource; (3) using substitute materials such as clinker, scoria, and recycled asphalt and concrete; and (4) using rail and water to transport aggregates from remote sources.

Open-File Report↗
USGS2013

Water resources and shale gas/oil production in the Appalachian Basin: critical issues and evolving developments

Unconventional natural gas and oil resources in the United States are important components of a national energy program. While the Nation seeks greater energy independence and greener sources of energy, Federal agencies with environmental responsibilities, state and local regulators and water-resource agencies, and citizens throughout areas of unconventional shale gas development have concerns about the environmental effects of high volume hydraulic fracturing (HVHF), including those in the Appalachian Basin in the northeastern United States (fig. 1). Environmental concerns posing critical challenges include the availability and use of surface water and groundwater for hydraulic fracturing; the migration of stray gas and potential effects on overlying aquifers; the potential for flowback, formation fluids, and other wastes to contaminate surface water and groundwater; and the effects from drill pads, roads, and pipeline infrastructure on land disturbance in small watersheds and headwater streams (U.S. Government Printing Office, 2012). Federal, state, regional and local agencies, along with the gas industry, are striving to use the best science and technology to develop these unconventional resources in an environmentally safe manner. Some of these concerns were addressed in U.S. Geological Survey (USGS) Fact Sheet 2009–3032 (Soeder and Kappel, 2009) about potential critical effects on water resources associated with the development of gas extraction from the Marcellus Shale of the Hamilton Group (Ver Straeten and others, 1994). Since that time, (1) the extraction process has evolved, (2) environmental awareness related to high-volume hydraulic fracturing process has increased, (3) state regulations concerning gas well drilling have been modified, and (4) the practices used by industry to obtain, transport, recover, treat, recycle, and ultimately dispose of the spent fluids and solid waste materials have evolved. This report updates and expands on Fact Sheet 2009–3032 and presents new information regarding selected aspects of unconventional shale gas development in the Appalachian Basin (primarily Virginia, West Virginia, Maryland, Pennsylvania, Ohio, and New York). This document was prepared by the USGS, in cooperation with the U.S. Department of Energy, and reviews the evolving technical advances and scientific studies made in the Appalachian Basin between 2009 and the present (2013), addressing past and current issues for oil and gas development in the region.

Maryl;New York;Ohio;Pennsylvania;Virginia;West Vir↗