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USGS2004

Modeling selenium bioaccumulation through arthropod food webs in San Francisco Bay, California, USA

Trophic transfer is the main process by which upper trophic level wildlife are exposed to selenium. Transfers through lower levels of a predator's food web thus can be instrumental in determining the threat of selenium in an ecosystem. Little is known about Se transfer through pelagic, zooplankton‐based food webs in San Francisco Bay ([SFB], CA, USA), which serve as an energy source for important predators such as striped bass. A dynamic multipathway bioaccumulation model was used to model Se transfer from phytoplankton to pelagic copepods to carnivorous mysids ( Neomysis mercedis ). Uptake rates of dissolved Se, depuration rates, and assimilation efficiencies (AE) for the model were determined for copepods and mysids in the laboratory. Small (73‐250 μm) and large (250‐500 μm) herbivorous zooplankton collected from SFB ( Oithona/Limnoithona and Acartia sp.) assimilated Se with similar efficiencies (41‐52%) from phytoplankton. Mysids assimilated 73% of Se from small herbivorous zooplankton; Se AE was significantly lower (61%) than larger herbivorous zooplankton. Selenium depuration rates were high for both zooplankton and mysids (12‐25% d −1 ), especially compared to bivalves (2‐3% d −1 ). The model predicted steady state Se concentrations in mysids similar to those observed in the field. The predicted concentration range (1.5‐5.4 μg g −1 ) was lower than concentrations of 4.5 to 24 μg g −1 observed in bivalves from the bay. Differences in efflux between mysids and bivalves were the best explanation for the differences in uptake. The results suggest that the risk of selenium toxicity to predators feeding on N. mercedis would be less than the risk to predators feeding on bivalves. Management of selenium contamination should include food webs analyses to focus on the most important exposure pathways identified for a given watershed.

California↗

USGS2005

Build-and-fill sequences: How subtle paleotopography affects 3-D heterogeneity of potential reservoir facies

This study analyzes the three-dimensional variability of a 20-meter-thick section of Pennsylvanian (Missourian) strata over a 600 km2 area of northeastern Kansas, USA. It hypothesizes that sea-level changes interact with subtle variations in paleotopography to influence the heterogeneity of potential reservoir systems in mixed carbonate-silidclastic systems, commonly produdng build-and-fill sequences. For this analysis, ten lithofacies were identified: (1) phylloid algal boundstone-packstone, (2) skeletal wackestone-packstone, (3) peloidal, skeletal packstone, (4) sandy, skeletal grainstone-packstone, (5) oolite grainstone-packstone, (6) Osagia-brachiopod packstone, (7) fossiliferous siltstone, (8) lenticular bedded-laminated siltstone and fine sandstone, (9) organic-rich mudstone and coal, and (10) massive mudstone. Each facies can be related to depositional environment and base-level changes to develop a sequence stratigraphy consisting of three sequence boundaries and two flooding surfaces. Within this framework, eighteen localities are used to develop a threedimensional framework of the stratigraphy and paleotopography. The studied strata illustrate the model of "build-and-fill". In this example, phylloid algal mounds produce initial relief, and many of the later carbonate and silidclastic deposits are focused into subtle paleotopographic lows, responding to factors related to energy, source, and accommodation, eventually filling the paleotopography. After initial buildup of the phylloid algal mounds, marine and nonmarine siliciclastics, with characteristics of both deltaic lobes and valley fills, were focused into low areas between mounds. After a sea-level rise, oolitic carbonates formed on highs and phylloid algal facies accumulated in lows. A shift in the source direction of siliciclastics resulted from flooding or filling of preexisting paleotopographic lows. Fine-grained silidclastics were concentrated in paleotopographic low areas and resulted in clay-rich phylloid algal carbonates that would have made poor reservoirs. In areas more distant from silidclastic influx, phylloid algal facies with better reservoir potential formed in topographic lows. After another relative fall in sea level, marine carbonates and silidclastics were concentrated in paleotopographic low areas. After the next relative rise in sea level, there is little thickness or fades variation in phylloid algal limestone throughout the study area because: (1) substrate paleotopography had been subdued by filling, and (2) no silidclastics were deposited in the area. Widespread subaerial exposure and erosion during a final relative fall in sea level resulted in redevelopment of variable paleotopography. Build-and-fill sequences, such as these, are well known in other surface and subsurface examples. Initial relief is built by folding or faulting, differential compaction, erosion, or deposition of relief-building facies, such as phylloid algal and carbonate grainstone reservoir fades, or silidclastic wedges. Relief is filled through deposition of reservoir-fades siliciclastics, phylloid algal fades, and grainy carbonates, as well as nonreservoir facies, resulting in complex heterogeneity.

AAPG Memoir↗

USGS2009

Thorium deposits of the United States — Energy resources for the future?

Many nations are exploring new ways to meet their growing energy supply needs, with a particular focus upon methods that produce lower carbon dioxide emissions compared to traditional oil, natural gas, and coal power plants. As a result, thorium-based nuclear power has experienced renewed attention as a potential energy source. Thus, it benefits the United States and other countries to identify and evaluate their indigenous thorium resources. This report describes the geology and resources of the principal thorium districts of the United States.

Circular↗

USGS2006

Navajo coal and air quality in Shiprock, New Mexico

Among the Navajo people, high levels of respiratory disease, such as asthma, exist in a population with low rates of cigarette smoking. Air quality outdoors and indoors affects respiratory health. Many Navajo Nation residents burn locally mined coal in their homes for heat, as coal is the most economical energy source. The U.S. Geological Survey and Dine College, in cooperation with the Navajo Division of Health, are conducting a study in the Shiprock, New Mexico, area to determine if indoor use of this coal might be contributing to some of the respiratory health problems experienced by the residents. Researchers in this study will (1) examine respiratory health data, (2) identify stove type and use, (3) analyze samples of coal that are used locally, and (4) measure and characterize air quality inside selected homes. This Fact Sheet summarizes the interim results of the study in both English and Navajo.

Fact Sheet↗

USGS2006

Navajo coal and air quality in Shiprock, New Mexico

Fact Sheet↗

USGS1982

Seismic reflection study of Flathead Lake, Montana

A seismic reflection survey of Flathead Lake, Montana, was carried out in 1970 to study the geologic structure underlying the lake. Approximately 200 km of track lines were surveyed resulting in about 140 km of useable data (Fig. 1). A one cu. in. air gun was used as the energy source. Navigation was by a series of theodolite sitings of the boat from pairs of shore-based control points.

Montana↗

USGS2004

Mineral, Energy, and Fertilizer Resources of the North Coast of Peru: Perspective from the Santa Rita B Archaeological Site

The Santa Rita B archaeological site is in the Chao Valley, approximately 65 km southeast of Trujillo, northern Peru. Location of Santa Rita B at the emergence of several drainages from the Andean cordillera is an important factor in the almost continuous occupation of the site over the past 3,000 years. Mineral resources are abundant throughout the Andes; however, the north coast of Peru was an important center for pre-Columbian mining, metallurgy, and craftsmanship. Success of the Chavin, Moche, Chimu, and other north coast cultures is directly related to the availability and exploitation of mineral and energy resources that include: gold (?silver), as electrum, mainly from placers, and copper from local oxide and carbonate occurrences and from sulfides related to copper porphyry occurrences in the cordillera. An alloy of these three metals is referred to as tumbaga, which is the primary material for Andean metalcraft. Anthracite was used for mirrors by north coast cultures and is available near Rio Chicama, Rio Santa, and east of Santa Rita B. These outcrops are a part of the Alto Chicama, Peru's largest coalfield, which extends from Rio Chicama, in the north, for 200 km southward to Rio Santa. Charcoal from the algorrobo tree and llama dung are considered to be the common pre-Columbian energy sources for cooking and metalwork; however, availability and the higher heat content of anthracite indicate that it was used in metallurgical applications. Bitumen is available from petroleum seeps near Talara, north of the study area, and may have been used as glue or as cement. Hematite, goethite, limonite, and manganese oxides from clay-altered volcanic rock may have provided color and material for ceramics. Guano from the Islas Gua?apes, Chinchas, and Ballestas was used as fertilizer for cotton and other crops.

Open-File Report↗

USGS2010

Environmental Assessment for a Marine Geophysical Survey of Parts of the Arctic Ocean, August-September 2010

According to the United Nations Convention on the Law of the Sea (UNCLOS), individual nations? sovereign rights extend to 200 nautical miles (n.mi.) (370 km) offshore or to a maritime boundary in an area called the continental shelf. These rights include jurisdiction over all resources in the water column and on and beneath the seabed. Article 76 of UNCLOS also establishes the criteria to determine areas beyond the 200 n.mi. (370 km) limit that could be defined as ?extended continental shelf,? where a nation could extend its sovereign rights over the seafloor and sub-seafloor (As used in UNCLOS, ?continental shelf? refers to a legally defined region of the sea floor rather than a morphological shallow-water area adjacent to continents commonly used by geologists and hydrographers.). This jurisdiction provided in Article 76 includes resources on and below the seafloor but not in the water column. The United States has been acquiring data to determine the outer limits of its extended continental shelf in the Arctic and has a vested interest in declaring and receiving international recognition of the reach of its extended continental shelf. The U.S. collaborated with Canada in 2008 and 2009 on extended continental shelf studies in the Arctic Ocean. The U.S. Coast Guard (USCG) Cutter Healy worked with the Canadian Coast Guard ship Louis S. St. Laurent to map the continental shelf beyond 200 n.mi. (370 km) in the Arctic. Each icebreaking vessel contributed different capabilities in order to collect data needed by both nations more efficiently in order to save money, avoid redundancy, and foster cooperation. Generally, the Healy collects bathymetric (sea-floor topography) data and the Louis S. St. Laurent collects seismic reflection profile data. The vessels work in concert when ice conditions are heavy, with one vessel breaking ice for the ship collecting data. The Canadian Environmental Assessments for these projects are available on line at http://www.ceaa.gc.ca/052/details-eng.cfm?pid=38185 (2008) and http://www.ceaa.gc.ca/052/details-eng.cfm?pid=46518 (2009). The U.S. Geological Survey (USGS) and Geological Survey of Canada (GSC) are undertaking a similar partnership again for 2010 in a limited area of U.S. waters during the period between ~10 and 16 August. The survey vessels will then proceed to international or Canadian waters where surveying will proceed until ~3 September, when the two icebreakers will separate to conduct independent work. The survey area of the joint work will be bounded approximately by 145? to 158? W longitude and 71? to 84? N latitude in water depths ranging from ~2,000 to 4,000 m (fig. 1). Ice conditions are expected to range from open water to 10/10 ice cover. The Louis S. St. Laurent will join accompanying vessel Healy in or near the survey area around 10 August to begin the joint survey work. As its energy source, the seismic system aboard Louis S. St. Laurent will employ a 3-airgun array consisting of three Sercel G-airguns. Two guns will have a discharge volume of 500 in3 and the third a discharge volume of 150 in3 for a total array discharge volume of 1,150 in3. The seismic survey will take place in water depths 2,000?4,000 m. This airgun array is identical to the system used in the 2008 and 2009 field programs by the Geological Survey of Canada. The USGS requested that the National Marine Fisheries Service (NMFS) issue an Incidental Harassment Authorization (IHA) to authorize the incidental, that is, not intentional, harassment of small numbers of cetaceans and seals should this occur during the seismic survey in U.S. waters. USGS is also consulting with the U.S. Fish and Wildlife Service (USFWS) regarding concerns about disturbance to walruses and polar bears. Through informal consultation with the Office of Protected Resources with the National Oceanic and Atmospheric Administration (NOAA), USGS proposes that no ESA-listed marine species?bowhead, fin, humpback or sperm whale?w

Open-File Report↗

USGS2011

Abbreviated bibliography on energy development—A focus on the Rocky Mountain Region

Energy development of all types continues to grow in the Rocky Mountain Region of the western United States. Federal resource managers increasingly need to balance energy demands, effects on the natural landscape and public perceptions towards these issues. To assist in efficient access to valuable information, this abbreviated bibliography provides citations to relevant information for myriad of issues for which resource managers must contend. The bibliography is organized by seven large topics with various sup-topics: broad energy topics (energy crisis, conservation, supply and demand, etc.); energy sources (fossil fuel, nuclear, renewable, etc.); natural landscape effects (climate change, ecosystem, mitigation, restoration, and reclamation, wildlife, water, etc.); human landscape effects (attitudes and perceptions, economics, community effects, health, Native Americans, etc.); research and technology; international research; and, methods and modeling. A large emphasis is placed on the natural and human landscape effects.

Idaho;Montana;Wyoming;Utah;Colorado;New Mexico;Ari↗

USGS2013

Role of stranded gas in increasing global gas supplies

This report synthesizes the findings of three regional studies in order to evaluate, at the global scale, the contribution that stranded gas resources can make to global natural gas supplies. Stranded gas, as defined for this study, is natural gas in discovered conventional gas and oil fields that is currently not commercially producible for either physical or economic reasons. The regional studies evaluated the cost of bringing the large volumes of undeveloped gas in stranded gas fields to selected markets. In particular, stranded gas fields of selected Atlantic Basin countries, north Africa, Russia, and central Asia are screened to determine whether the volumes are sufficient to meet Europe’s increasing demand for gas imports. Stranded gas fields in Russia, central Asia, Southeast Asia, and Australia are also screened to estimate development, production, and transport costs and corresponding gas volumes that could be supplied to Asian markets in China, India, Japan, and South Korea. The data and cost analysis presented here suggest that for the European market and the markets examined in Asia, the development of stranded gas provides a way to meet projected gas import demands for the 2020-to-2040 period. Although this is a reconnaissance-type appraisal, it is based on volumes of gas that are associated with individual identified fields. Individual field data were carefully examined. Some fields were not evaluated because current technology was insufficient or it appeared the gas was likely to be held off the export market. Most of the evaluated stranded gas can be produced and delivered to markets at costs comparable to historical prices. Moreover, the associated volumes of gas are sufficient to provide an interim supply while additional technologies are developed to unlock gas diffused in shale and hydrates or while countries transition to making a greater use of renewable energy sources.

Open-File Report↗

USGS2014

Coalbed natural gas exploration, drilling activities, and geologic test results, 2007-2010

The U.S. Geological Survey, in partnership with the U.S. Bureau of Land Management, the North Slope Borough, and the Arctic Slope Regional Corporation conducted a four-year study designed to identify, define, and delineate a shallow coalbed natural gas (CBNG) resource with the potential to provide locally produced, affordable power to the community of Wainwright, Alaska. From 2007 through 2010, drilling and testing activities conducted at three sites in or near Wainwright, identified and evaluated an approximately 7.5-ft-thick, laterally continuous coalbed that contained significant quantities of CBNG. This coalbed, subsequently named the Wainwright coalbed, was penetrated at depths ranging from 1,167 ft to 1,300 ft below land surface. Core samples were collected from the Wainwright coalbed at all three drill locations and desorbed-gas measurements were taken from seventeen 1-ft-thick sections of the core. These measurements indicate that the Wainwright coalbed contains enough CBNG to serve as a long-term energy supply for the community. Although attempts to produce viable quantities of CBNG from the Wainwright coalbed proved unsuccessful, it seems likely that with proper well-field design and by utilizing currently available drilling and reservoir stimulation techniques, this CBNG resource could be developed as a long-term economically viable energy source for Wainwright.

Alaska↗

USGS2016

Mortality monitoring design for utility-scale solar power facilities

Introduction Solar power represents an important and rapidly expanding component of the renewable energy portfolio of the United States (Lovich and Ennen, 2011; Hernandez and others, 2014). Understanding the impacts of renewable energy development on wildlife is a priority for the U.S. Fish and Wildlife Service (FWS) in compliance with Department of Interior Order No. 3285 (U.S. Department of the Interior, 2009) to “develop best management practices for renewable energy and transmission projects on the public lands to ensure the most environmentally responsible development and delivery of renewable energy.” Recent studies examining effects of renewable energy development on mortality of migratory birds have primarily focused on wind energy (California Energy Commission and California Department of Fish and Game, 2007), and in 2012 the FWS published guidance for addressing wildlife conservation concerns at all stages of land-based wind energy development (U.S. Fish and Wildlife Service, 2012). As yet, no similar guidelines exist for solar development, and no published studies have directly addressed the methodology needed to accurately estimate mortality of birds and bats at solar facilities. In the absence of such guidelines, ad hoc methodologies applied to solar energy projects may lead to estimates of wildlife mortality rates that are insufficiently accurate and precise to meaningfully inform conversations regarding unintended consequences of this energy source and management decisions to mitigate impacts. Although significant advances in monitoring protocols for wind facilities have been made in recent years, there remains a need to provide consistent guidance and study design to quantify mortality of bats, and resident and migrating birds at solar power facilities (Walston and others, 2015). In this document, we suggest methods for mortality monitoring at solar facilities that are based on current methods used at wind power facilities but adapted for the unique conditions encountered at solar facilities. In particular, unlike at wind-power facilities, the unimpeded access to almost all areas within the facilities, the typically flat terrain, and general absence of thick vegetation allow distance-sampling techniques (Buckland and others, 2001, 2004) to be exploited to advantage at industrial solar sites. These protocols build on the work of Nicolai and others (2011), and as our understanding and techniques for monitoring improve, the methods may be further modified to incorporate improvements in the future. We present case studies based on monitoring methods currently implemented at different utility-scale solar facilities to illustrate how distance-sampling techniques may improve overall detectability without substantially increasing costs. Every facility is unique, and the protocols presented may be adapted based on specific monitoring objectives and conditions at each site. We provide guidance for designing monitoring programs whose objective it is to estimate the total number of bird and bat fatalities occurring at a facility over an extended period of time. We address spatial variation in causes of mortality, as well as potential sources of imperfect detection, for example, animals falling in or moving to unsearched areas, carcasses removed by predators, and carcasses missed by searchers. We suggest methods to estimate and account for each source of imperfect detection. This document focuses on monitoring design only and does not discuss approaches for estimating mortality from collected data. The development of statistically sound estimators relevant to the solar context is a current topic of research, although there are already strong foundations for estimation with distance-sampling methods in similar open, arid environments (Anderson and others, 2001; Freilich and others, 2005). Nonetheless, if protocols described in this document are followed, the resulting data will be adequate and sufficient for estimating mortality using newly formulated estimators.

Open-File Report↗

USGS1979

Outer continental shelf oil and gas information program; Alaska index (December 1974 - June 1979)

As part of a national goal to reduce dependence on foreign energy sources, the United States is currently managing a program for leasing of OCS oil and gas resources. The areas potentially affected, consisting of 22 coastal states and Pennsylvania, can be grouped into four major areas: Alaska, Atlantic, Gulf of Mexico and Pacific. The Alaska Area has three lease sale areas: Gulf of Alaska, the Bering Sea and the Chukchi and the Beaufort Sea (see Figures I and 2). Most of the information used by both the government and industry on the hydrocarbon potential of the Alaska Area is initially acquired and compiled on a regional basis. These data are used by industry in nominating tracts for lease and in preparation of bids and by the Department of the Interior for general sale area identification, tract selection, environmental impact statements and resource evaluation. Subsequent environmental information and data analysis is directed toward defining specific sub-areas and site-specific evaluation.

Alaska↗

USGS1984

Seismic refraction studies in the San Juan Basin, Northwest New Mexico

The U.S. Geological Survey is studying some of the features of the earth's crust in the San Juan Basin region, northwest New Mexico. As a part of this study seismic refraction-reflection measurements were made in and around the basin using explosions and earthquakes as energy sources. Record sections and traveltime tables were derived from the measurements.

Open-File Report↗

USGS1983

Distribution and quantitative assessment of world crude oil reserves and resources

World Demonstrated Reserves of crude oil are approximately 723 billion barrels of oil (BBO). Cumulative production is 445 BBO and annual production is 20 BBO. Demonstrated Reserves of crude-oil have declined over the past 10 years consistent with discoveries lagging production over the same period. The assessment of Undiscovered Resources shows a 90 percent probability that the amount discoverable lies between 321 and 1,417 BBO, 550 BBO being the most likely value. The most likely value for Ultimate recoverable resources is 1,718 BBO. The distribution of Ultimate Resources of crude oil will remain highly skewed toward the Middle East; no frontier areas that have potentials large enough to significantly affect present distribution are recognized. Rates of discovery have continued to decline over the past 20 years even though exploration activity has increased in recent years. Prudence dictates, therefore, that the low side of the assessment of Undiscovered Resources be responsibly considered and that alternate energy sources be a part of future planning. Extra-heavy oil and bitumen are assessed separately, with Reserves being figured as the annual productive capacity of installed facilities times 25 years. The annual production of extra-heavy oil is about 8 million barrels and of bitumen about 60 million barrels.

Open-File Report↗

USGS1994

Subsurface investigation for liquefaction analysis and piezometer calibration at Treasure Island Naval Station, California

Between January and March, 1994, a drilling program was conducted at the Treasure Island Naval Station to evaluate the liquefaction resistance of soils that did and did not liquefy during the Loma Prieta, California, earthquake of October 17, 1989. A second goal of this drilling program was to test and calibrate a retrievable piezometer system that is designed to monitor dynamic pore-water pressure during liquefaction. Retrievable Piezometer A retrievable piezometer can be used to replace failed transducers without redrilling, and the external casing can be installed without the piezometer itself. Many external casings can be installed throughout a region and used only when necessary. At two sites the USGS retrievable piezometer was placed at depths between 2.3 and 4.6m. The retrievable piezometer involves augering a hole to the testing depth and emplacing a 33-mm outside diameter pvc pipe with a porous stone. The hole is back filled and sealed with bentonite, the top of the boring is capped with a box flush to the ground. Later, a commercial transducer is connected to a 21-mm outside diameter pvc pipe and lowered down the 33 mm casing and screwed into the bottom porous-stone assembly. A calibrating transducer (the same type and model as in the USGS retrievable piezometer) was installed inside a penetrometer with a 60° conical tip and an external sleeve that protects the porous filter, located immediately behind the tip, during advancement through dry soil. After the instrument was advanced to the proper depth the tip with the porous filter was advanced past the protective sleeve. Pore pressure was elevated separately by dynamic impact and blasting. The first calibration tests were conducted within the U.S. Geotechnical Test Site established at the Treasure Island fire station (building 157) (de Alba and others, 1994). A 590 kg weight (diameter 72 cm) was dropped 0.69 to 1.63 m onto a steel plate (91 cm square, 0.6 cm thick) to elevate pore pressure, each test involved dropping the weight one time. The surficial distance from the energy source to the piezometers ranged from 1 to 3.6 m. At an empty field (bounded by 11th and 13th streets and H and I ave) pore pressure was elevated using the 590 kg weight and no. 8 blasting caps (50 grains, 3 grams) and primer cord. The explosives were placed 2 m from the piezometers at depths of 2.4 to 2.7 m. A USGS explosives expert handled the explosives under the supervision of Navy personnel. Liquefaction Gray and brown, fine to medium grained sand was hydraulically dredged from San Francisco Bay to create Treasure Island (fig. 1). During the Loma Prieta earthquake Treasure Island experience a peak ground acceleration of 0.16 g (Shakal and other, 1989) and portions of the soil beneath Treasure Island liquefied and were vented to the ground surface as sand boils. During November, 1989, a survey of Treasure Island was made to document ground effects such as sand boils, settlement, and ground cracking. During this survey samples of more than 30 sand boils were taken for grain size analysis (Bennett, in press). Although the soil beneath the fire station did not liquefy, surrounding areas did. The surrounding liquefaction may have affected the peak ground acceleration. Fifteen seconds into the acceleration record at the fire station there is a sudden drop in ground acceleration, and 16 seconds into the record there is practically no response (Idriss, 1991). De Alba and others (1994) ascribe the behavior of the acceleration record to the liquefaction of the underlying sand. Besides the generation of sand boils, Treasure Island experienced significant ground settlement and lateral deformation that damaged lifelines for water and gas (Seed and others, 1990). The primary objective of this report is to document the subsurface stratigraphy at the liquefaction and non-liquefaction sites (fig. 2), and to explore the relation between sand boils and subsurface sediment. This documentation adds to the geotechnical data base of liquefaction by clarifying which layers actually liquefy during earthquakes. Another objective is to briefly describe the piezometer calibration test in terms of what was done and where it was done, results of the calibration work will be reported later by the primary investigator, Behnam Hushmand of Hushmand Associates.

California↗

USGS1997

The Areal Extent of Continuous Type Gas Accumulations in Lower Silurian Clinton Sands and Medina Group Sandstones of the Appalachian Basin and the Environments Affected by Their Development

In order to best preserve and manage our energy and natural resources we must understand the relationships between these resources and the impacts of their development. To further this understanding the U.S. Geological Survey is studying unconventional continuous-type and, to a lesser extent, conventional oil and gas accumulations and the environmental impacts associated with their development. Continuous-type gas accumulations are generally characterized by low matrix permeabilities, large areal extents, and no distinct water contacts. This basin scale map shows the overall extent of these accumulations and the general land use types that may be impacted by their development. The Appalachian Basin has the longest history of oil and gas exploration and production in the United States. Since Drake's Titusville discovery well was drilled in 1859, oil and gas has been continuously produced in the basin. While there is still a great deal of oil and gas production, new field discoveries are rare and relatively small. For most of the second half of the 20th century the Appalachian basin has been considered a mature petroleum province because most of the large plays have already been discovered and developed. One exception to this trend is the Lower Silurian Clinton Sands and Medina Group Gas play which is being developed in New York, Pennsylvania, and Ohio. This continuous-type gas play has been expanding since the early 1970's (see inset maps). In the 1980's economic incentives such as large increases in wellhead prices further stimulated continuous-type gas resource development. Continuous-type gas plays can be large in areal extent and in thickness. 'Sweetspots' (areas of greater prodcution) are hard to predict and generally associated with better than average permeabilities, and enhanced by natural fracture systems. With an overall success rate often approaching 90%, drilling most of the play with closely spaced wells is often the best way to maximize gas recovery. Some positive economic characteristics associated with the development of these continuous-type accumulations are high success rates, low drilling and development costs, and low water production, which results in low water disposal costs. Large areas within the Appalachian basin with good potential for this type of gas accumulation remain to be tested. Positive environmental characteristics include, a clean energy source, low water production, and relatively low surface impact. Some negative characteristics associated with these continuous -type accumulations are low individual well production rates and small well drainage area. Negative environmental characteristics are primarily related to the dense well spacing used to develop the resource to its full potential. Often negative environmental impacts such as surface disturbance can be greatly reduced. The number of well sites can be decreased by using a single centrally located surface location and associated facilities for several directionally or horizonatally drilled wells. This also minimizes the transportation infrastructure (access roads and pipelines) required to maintain the wells and deliver the gas. Visual impacts can be reduced by selecting well locations visible only over short distances. While the prospective area is large, potential decreases basin- ward and toward the northeast and southwest. These areas are represented by the lower potential plays 6727, 6730, and 6731. The U.S. Geological Survey landuse and landcover data was derived from USGS 1:250,000 and 1:100,000 scale maps. This information was collected between the mid 1970s to mid 1980s. The land use and land cover data was mapped and coded using the Anderson classification system (Anderson, 1975) which is a hierarchical system of general (level 1) to more specific (level 2) characterization. Level 1 characterization was used for this map; the land use and land cover designations are displayed below in the Explanation. T

Open-File Report↗

USGS2013

Brookian sequence well log correlation sections and occurrence of gas hydrates, north-central North Slope, Alaska

Gas hydrates are naturally occurring crystalline, ice-like substances that consist of natural gas molecules trapped in a solid-water lattice. Because of the compact nature of their structure, hydrates can effectively store large volumes of gas and, consequently, have been identified as a potential unconventional energy source. First recognized to exist geologically in the 1960s, significant accumulations of gas hydrate have been found throughout the world. Gas hydrate occurrence is limited to environments such as permafrost regions and subsea sediments because of the pressure and temperature conditions required for their formation and stability. Permafrost-associated gas hydrate accumulations have been discovered in many regions of the Arctic, including Russia, Canada, and the North Slope of Alaska. Gas hydrate research has a long history in northern Alaska. This research includes the drilling, coring, and well log evaluation of two gas hydrate stratigraphic test wells and two resource assessments of gas hydrates on the Alaska North Slope. Building upon these previous investigations, this report provides a summary of the pertinent well log, gas hydrate, and stratigraphic data for key wells related to gas hydrate occurrence in the north-central North Slope. The data are presented in nine well log correlation sections with 122 selected wells to provide a regional context for gas hydrate accumulations and the relation of the accumulations to key stratigraphic horizons and to the base of the ice-bearing permafrost. Also included is a well log database that lists the location, available well logs, depths, and other pertinent information for each of the wells on the correlation section.

Alaska↗