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At least 1,693 records · Page 94Linked to original sources

Economics and the 1995 National Assessment of U.S. oil and gas resources

This report summarizes the economic component of the U.S. Geological Survey's 1995 National Assessment of oil and gas resources for the US onshore areas and State waters. This area accounts for 80 percent of US hydrocarbon production and 85 percent of US proved reserves. The Minerals Management Service has released a parallel study for Federal offshore areas (1996). Estimates are as of January 1994. The economic evaluation uses mean values of the technically recoverable resources assessed by geologists.

Open-File Report↗

Computer input and output files associated with ground-water-flow simulations of the Albuquerque Basin, central New Mexico, 1901-95, with projections to 2020; (supplement three to U.S. Geological Survey Water-resources investigations report 94-4251)

This report presents the computer input files required to run the three-dimensional ground-water-flow model of the Albuquerque Basin, central New Mexico, documented in Kernodle and others (Kernodle, J.M., McAda, D.P., and Thorn, C.R., 1995, Simulation of ground-water flow in the Albuquerque Basin, central New Mexico, 1901-1994, with projections to 2020: U.S. Geological Survey Water-Resources Investigations Report 94-4251, 114 p.) and revised by Kernodle (Kernodle, J.M., 1998, Simulation of ground-water flow in the Albuquerque Basin, 1901-95, with projections to 2020 (supplement two to U.S. Geological Survey Water-Resources Investigations Report 94-4251): U.S. Geological Survey Open-File Report 96-209, 54 p.). Output files resulting from the computer simulations are included for reference.

Open-File Report↗

Water-resources investigations in Wisconsin

PROBLEM: Surface-water information is needed for surveillance, planning, design, hazard warning, operation, and management in water-related fields such as water supply, hydroelectric power, flood control, irrigation, bridge and culvert design, wildlife management, pollution abatement, flood-plain management, and water-resources development. An appropriate data base is necessary to provide this information. OBJECTIVE: The objectives of this study are to provide continuous discharge records for selected rivers at specific sites to supply the needs for regulation, analytical studies, definition of statistical properties, trends analysis, determination of the occurrence, and distribution of water in streams for planning. The project is also LOCATION: Statewide PROJECT CHIEF: Barry K. Holmstrom PERIOD OF PROJECT: July 1913-Continuing designed to determine lake levels and to provide discharge for floods, low-flow conditions, and for waterquality investigations. Requests for streamflow data and information relating to streamflow in Wisconsin are answered. Basic data are published annually in the report "Water Resources Data-Wisconsin."

Wisconsin↗

The role of mineral resource assessments in ecological stewardship

Bedrock geology and mineral resource assessments can provide important information for ecologically based stewardship of land and water. Combining information derived from mineral resource assessments and geoenvironmental mineral deposit models provides a means to rapidly screen a large region for potential for mineral concentrations, to assess the environmental risk associated with mineralized bedrock and with human disturbances of mineralized bedrock, and to establish priorities for further studies.

Open-File Report↗

National Geochemical Database: Reformatted data from the National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program

The National Uranium Resource Evaluation (NURE) Hydrogeochemical and Stream Sediment Reconnaissance (HSSR) program produced a large amount of geochemical data. To fully understand how these data were generated, it is recommended that you read the History of NURE HSSR Program for a summary of the entire program. By the time the NURE program had ended, the HSSR data consisted of 894 separate data files stored with 47 different formats. Many files contained duplication of data found in other files. The University of Oklahoma's Information Systems Programs of the Energy Resources Institute (ISP) was contracted by the Department of Energy to enhance the accessibility and usefulness of the NURE HSSR data. ISP created a single standard-format master file to replace the 894 original files. ISP converted 817 of the 894 original files before its funding apparently ran out. The ISP-reformatted NURE data files have been released by the USGS on CD-ROM (Lower 48 States, Hoffman and Buttleman, 1994; Alaska, Hoffman and Buttleman, 1996). A description of each NURE database field, derived from a draft NURE HSSR data format manual (unpubl. commun., Stan Moll, ISP, Oct 7, 1988), was included in a readme file on each CD-ROM. That original manual was incomplete and assumed that the reformatting process had gone to completion. A lot of vital information was not included. Efforts to correct that manual and the NURE data revealed a large number of problems and missing data. As a result of the frustrating process of cleaning and re-cleaning data from the ISP-reformatted NURE files, a new NURE HSSR data format was developed. This work represents a totally new attempt to reformat the original NURE files into 2 consistent database structures; one for water samples and a second for sediment samples, on a quadrangle by quadrangle basis, from the original NURE files. Although this USGS-reformatted NURE HSSR data format is different than that created by the ISP, many of their ideas were incorporated and expanded in this effort. All of the data from each quadrangle are being examined thoroughly in an attempt to eliminate problems, to combine partial or duplicate records, to convert all coding to a common scheme, and to identify problems even if they can not be solved at this time.

Open-File Report↗

Geology and mineral resources of the Lake Valley area, Sierra County, New Mexico

At the request of the Bureau of Land Management, the U.S. Geological Survey assessed the Lake Valley Area of Critical Environmental Concern (ACEC), which includes the historic Lake Valley townsite and silver-manganese mining district, for undiscovered mineral resources. The Lake Valley ACEC is along the southeastern margin of the Black Range of western Sierra County, New Mexico. The Black Range contains eleven mining districts from which silver, lead, zinc, manganese, copper, gold, and tin have been recovered. As part of the study, an area of over 75 square mi (195 square km) in the area of the Lake Valley ACEC was mapped to understand ore controls and to assess mineral-resource potential. Lake Valley mining district is in Mississippian Lake Valley Formation carbonate rocks, but much of the surrounding terrane consists of volcanic rocks on the southeastern edge of the Emory cauldron which formed about 34.9 Ma. Volcanic rocks are part of the Mogollon-Datil volcanic province which include flows, breccias, ash-flow tuffs, and intrusive rhyolites. The Lake Valley mining district is located about 20 mi (32 km) south of the Late Cretaceous Laramide copper-gold porphyry intrusion at Hillsboro. It is also located at the western boundary of the Rio Grande rift basin.The Lake Valey fault is the major structural feature of the study area. Geological and geophysical data suggest the fault is composed of two segments: a southern, northwest-striking segment that may have a pre-Tertiary history and a northerly-striking segment that is part of the Emory cauldron ring fracture. The mining district is bounded by the southern, northwest-striking segment of the fault which may have up to 800 ft (240m) of normal offset. Deposit types identified in the Black Range, and for which we assess mineral potential, are Laramide porphyry, Laramide skarns, Laramide veins, gold placer, carbonate-hosted, volcanic-epithermal, and rhyolite tin; no Rio Grande Rift baritefluorite-galena deposits are known, but they are included in the assessment. The most likely deposits to be discovered in the Lake Valley district are carbonate-hosted silver-manganese deposits. These deposits could be deposited by hydrothermal fluids or be related to intrusion of Oligocene rhyolite or Laramide porphyry. An aeromagnetic high south of the district probably reflects a small felsic intrusion of unknown age. We assess the Lake Valley ACEC as having low to moderate potential for undiscovered carbonate-hosted deposits associated with volcanic rocks or Laramide porphyry plutons, and low potential for gold placer and rhyolite tin deposits.

New Mexico↗

World conventional crude oil and natural gas: Identified reserves, undiscovered resources and futures

This report summarizes, at the petroleum basin level, the United States Geological Survey's World Energy Program 1993 assessment of world conventional oil and gas resources. The maps provided show boundaries of petroleum basins that are referenced by the assessment, as well as, future oil and gas potential. The 'Futures' or future potential of a basin is calculated as the the sum of the Identified Reserves and the modal value assigned to the conventional Undiscovered Resources.

Open-File Report↗

High-resolution seismic reflection/refraction imaging from Interstate 10 to Cherry Valley Boulevard, Cherry Valley, Riverside County, California: Implications for water resources and earthquake hazards

This report is the second of two reports on seismic imaging investigations conducted by the U.S. Geological Survey (USGS) during the summers of 1997 and 1998 in the Cherry Valley area in California (Figure 1a). In the first report (Catchings et al., 1999), data and interpretations were presented for four seismic imaging profiles (CV-1, CV-2, CV-3, and CV-4) acquired during the summer of 1997 . In this report, we present data and interpretations for three additional profiles (CV-5, CV-6, and CV-7) acquired during the summer of 1998 and the combined seismic images for all seven profiles. This report addresses both groundwater resources and earthquake hazards in the San Gorgonio Pass area because the shallow (upper few hundred meters) subsurface stratigraphy and structure affect both issues. The cities of Cherry Valley and Beaumont are located approximately 130 km (~80 miles) east of Los Angeles, California along the southern alluvial fan of the San Bernardino Mountains (see Figure 1b). These cities are two of several small cities that are located within San Gorgonio Pass, a lower-lying area between the San Bernardino and the San Jacinto Mountains. Cherry Valley and Beaumont are desert cities with summer daytime temperatures often well above 100 o F. High water usage in the arid climate taxes the available groundwater supply in the region, increasing the need for efficient management of the groundwater resources. The USGS and the San Gorgonio Water District (SGWD) work cooperatively to evaluate the quantity and quality of groundwater supply in the San Gorgonio Pass region. To better manage the water supplies within the District during wet and dry periods, the SGWD sought to develop a groundwater recharge program, whereby, excess water would be stored in underground aquifers during wet periods (principally winter months) and retrieved during dry periods (principally summer months). The SGWD preferred a surface recharge approach because it could be less expensive than a recharging program based on injection wells. However, at an existing surface recharge site, surface recharge of the aquifer was limited by the presence of clayrich layers that impede the downward percolation of the surface water. In boreholes, these clay-rich layers were found to extend from the near surface to about 50 m depth. If practical, the SGWD desired to relocate the recharge ponds to another location within the Cherry Valley–Beaumont area. This required that sites be found where the clay-rich layers were absent. The SGWD elected to explore for such sites by employing a combination of drilling and seismic techniques. A number of near-surface faults have been suggested in the Cherry Valley-Beaumont area (Figure 1b). However, there may be additional unmapped faults that underlie the alluvial valley of San Gorgonio Pass. Because faults are known to act as barriers to lateral groundwater flow in alluvial groundwater systems, mapped and unmapped subsurface faults in the Cherry Valley-Beaumont area would likely influence groundwater flow and the lateral distribution of recharged water. These same faults may pose a significant hazard to the local desert communities and to greater areas of southern California due to the presence of lifelines (water, electrical, gas, transportation, etc.) that extend through San Gorgonio Pass to larger urban areas. The three principal goals of the seismic investigation presented in this report were to laterally map the subsurface stratigraphic horizons, locate faults that may act as barriers to groundwater flow, and measure velocities of shallow sediments that may give rise to amplified shaking during major earthquakes.

California↗

National coal resource assessment non-proprietary data: Location, stratigraphy, and coal quality for selected tertiary coal in the Northern Rocky Mountains and Great Plains region

One of the objectives of the National Coal Resource Assessment in the Northern Rocky Mountains and Great Plains region was to compile stratigraphic and coal quality-trace-element data on selected and potentially minable coal beds and zones of the Fort Union Formation (Paleocene) and equivalent formations. In order to implement this objective, drill-hole information was compiled from hard-copy and digital files of the: (1) U.S. Bureau of Land Management (BLM) offices in Casper, Rawlins, and Rock Springs, Wyoming, and in Billings, Montana, (2) State geological surveys of Montana, North Dakota, and Wyoming, (3) Wyoming Department of Environmental Quality in Cheyenne, (4) U.S. Office of Surface Mining in Denver, Colorado, (5) U.S. Geological Survey, National Coal Resource Data System (NCRDS) in Reston, Virginia, (6) U.S. Geological Survey coal publications, (7) university theses, and (8) mining companies.

Open-File Report↗

Reconnaissance of the hydrothermal resources of Utah

Geologic factors in the Basin and Range province in Utah are more favorable for the occurrence of geothermal resources than in other areas on the Colorado Plateaus or in the Middle Rocky Mountains. These geologic factors are principally crustal extension and crustal thinning during the last 17 million years. Basalts as young as 10,000 years have been mapped in the area. High-silica volcanic and intru­sive rocks of Quaternary age can be used to locate hydrothermal convection systems. Drilling for hot, high-silica, buried rock bodies is most promising in the areas of recent volcanic activity. Southwestern Utah has more geothermal potential than other parts of the Basin and Range province in Utah. The Roosevelt Hot Springs area, the Cove Fort-Sulphurdale area, and the area to the north as far as 60 kilome­ters from them probably have the best potential for geothermal devel­opment for generation of electricity. Other areas with estimated res­ervoir temperatures greater than 150°C are Thermo, Monroe, Red Hill (in the Monroe-Joseph Known Geothermal Resource Area), Joseph Hot Springs, and the Newcastle area. The rates of heat and water discharge are high at Crater, Meadow, and Hatton Hot Springs, but estimated reservoir temperatures there are less than 150°C. Ad­ditional exploration is needed to define the potential in three ad­ditional areas in the Escalante Desert.

Utah↗

Geology and mineral resources of the Mud Springs Ranch Quadrangle, Sweetwater County, Wyoming

The Mud Springs Ranch quadrangle occupies an area of 56 mF (square miles) on the southeast flank of the Rock Springs uplift in southwestern Wyoming. The climate is arid and windy. The landscape is mostly poorly vegetated and consists of north-trending ridges and valleys that are dissected by dry drainages. Sedimentary rocks exposed in the quadrangle are 5,400 ft (feet) thick and are mostly gray sandstone, siltstone, and shale, gray and brown carbonaceous shale, and thin beds of coal. They compose the Blair, Rock Springs, Ericson, Almond, and Lewis Formations of Cretaceous age and the Fort Union Formation of Paleocene age. The structure is mostly homoclinal, having southeast dips of 5?-12? in the northern part of the quadrangle, but minor plunging folds and one small fault are present in the southern part of the quadrangle. Three coal beds in the Fort Union Formation and 15 coal beds in the Almond Formation exceed 2.5 ft in thickness, are under less than 3,000 ft of overburden, and are potentially minable. Geographic stratigraphic, and resource data are present for each bed of minable coal. The total minable coal resources are estimated to be about 283 million short tons. Nine coal and rock samples from outcrops were analyzed to determine their quality and chemical composition. Four dry oil and gas test wells have been drilled within the quadrangle area, but structurally controlled stratigraphic-trap prospects remain untested.

Professional Paper↗

Water resources and potential hydrologic effects of oil-shale development in the southeastern Uinta Basin, Utah and Colorado

Proposed oil-shale mining in northeastern Utah is expected to impact the water resources of a 3,000-square-mile area. This report summarizes a comprehensive hydrologic investigation of the area which resulted in 13 published reports. Hydrologic information obtained during 1974-80 was used to evaluate the availability of water and to evaluate potential impacts of an oil-shale industry on the water resources. The study area is the southeastern part of the Uinta Basin, Utah and Colorado, where the hydrology is extremely variable. The normal annual precipitation averages 11 inches and varies with altitude. It ranges from less than 8 inches at altitudes below 5,000 feet along the White and Green Rivers to more than 20 inches where altitudes exceed 9,000 feet on the Roan Plateau. The White and Green Rivers are large streams that flow through the area. They convey an average flow of 4.3 million acre-feet per year from outside drainage areas of about 34,000 square miles, which is more than 150 times as much flow as that originating within the area. Streams originating in areas where precipitation is less than 10 inches are ephemeral. Mean annual runoff from the study area is about 28,000 acre-feet and ranges from less than 0.1 to 1.6 inches, depending on the location. At any given site, runoff varies greatly-from year to year and season to season. Potential evapotranspiration is large, exceeding precipitation in all years. Three major aquifers occur in the area. They are alluvial deposits of small areal extent along the major stream valleys; the bird's-nest aquifer of the Parachute Creek Member of the Green River Formation, which is limited to the central part of the study area; and the Douglas Creek aquifer of the Douglas Creek Member of the Green River Formation, which underlies most of the area. Total recoverable water in storage in the three aquifers is about 18 million acre-feet. Yields of individual wells and interference between wells limit the maximum practical withdrawal to about 20,000 acre-feet per year. An oil-shale industry in the southeastern Uinta Basin with a peak production of 400,000 barrels of oil per day would require a water supply of about 70,000 acre-feet per year. Sources of water supply considered for such an industry were: diversion from the natural flow of the White River, a proposed reservoir on the White River, diversion from the White River combined with proposed off-stream storage in Hells Hole Canyon, diversion from the Green River, and conjunctive use of ground and surface water. The proposed reservoir on the White River would trap about 90 percent of the sediment moving in the river and in turn would release almost sediment-free water. Possible impacts are changes in channel gradient in the downstream 18 miles of the White River and changes in bank stability. In some parts of the area, annual sheet-erosion rates are as great as 2.2 acre-feet per square mile but sediment yield to the White River is less than might be expected because the runoff is small. If process water from retort operations or water used in the construction of surface facilities is discharged into a normally dry streambed, increased channel erosion and sediment in tributary streams could result in increased sediment loads in the White River. In addition, sediment yields from retorted-shale piles with minimum slopes could exceed 0.1 acrefoot per square mile during a common storm. Thus, without safeguards, the useful life of any proposed reservoir or holding pond could be decreased considerably. Leachate water from retorted-shale piles has large concentrations of sodium and sulfate, and the chemical composition of retort waters differs considerably from that of the natural waters of the area. The retort waters contain a greater concentration of dissolved solids and more organic carbon and nutrients. Without proper disposal or impoundment of retort and leachate waters, the salinity of downstream waters in the Colorado River Basin would be increased.

Colorado, Utah↗

Coal and petroleum resources in the Appalachian basin: index maps of included studies

This chapter B.1 of U.S. Geological Survey (USGS) Professional Paper 1708 provides index maps for many of the studies described in other chapters of the report. Scientists of the USGS and State geological surveys studied coal and petroleum resources in the central and southern Appalachian structural basins. In the southern Appalachian basin, studies focused on the coal-bearing parts of the Black Warrior basin in Alabama. The scientists used new and existing geologic data sets to create a common spatial geologic framework for the fossil-fuel-bearing strata of the central Appalachian basin and the Black Warrior basin in Alabama. Digital data have been compiled into a geographic information system (GIS) that is included in chapter I.1 (Trippi and others, this volume). Shape files and related metadata for features shown in the index maps of this chapter can be downloaded from chapter I.1. The study area for the Appalachian basin resource framework study includes the fossil-fuel-bearing strata of the following States (listed alphabetically): Alabama, Kentucky, Maryland, New York, Ohio, Pennsylvania, Tennessee, Virginia, and West Virginia. The outline of the study area is shown in figure 1; it differs from the boundary of the Appalachian Basin Province (Province 67) defined for the 1995 National Oil and Gas Assessment (NOGA) by the U.S. Geological Survey (1996a). The difference is that the study area includes regions where the Pennsylvanian coal-bearing strata crop out but does not include all of the oil- and gas-bearing strata of the Black Warrior basin, Alabama. The reasons for providing the index maps in this chapter are to show the locations of different studies, to give an overview of topics covered, and to help the user choose which chapter to read. Figures 1 and 2 show the study area outline and county names. Figure 3 shows oil and gas production in 1995 and 2005. Figure 4 shows locations of Upper Devonian sandstone oil and gas fields. Figure 5 shows major coal regions and coal fields. Figure 6 shows coal production by county. Figure 7 shows the locations of 10 cross sections of regional extent through the subsurface of the Appalachian basin. Figure 8 shows conodont alteration index sample locations and interpreted isograds for Ordovician rocks. Figure 9 shows vitrinite-reflectance data for Pennsylvanian coal in the Appalachian basin. Figure 10 shows the locations of coalbed-methane (CBM) assessment units in the study area, and figure 12 shows counties producing CBM. Figure 12 shows sulfur content of coal delivered to powerplants from coal-producing counties in the Appalachian basin and Black Warrior basin. Figure 13 shows locations of wells in Ohio and Pennsylvania where oil and gas were sampled in Lower Silurian reservoirs. Figure 14 shows the Conasauga-Rome/Conasauga Total Petroleum System and selected wells in the Rome trough in Kentucky and West Virginia having oil and gas production and shows. Figure 15 shows the locations of samples from Silurian reservoirs in Kentucky, New York, Ohio, Pennsylvania, and West Virginia; the samples yielded total organic carbon data. Figure 16 shows the locations of the Ben Hur and Rose Hill oil fields, Virginia, and the Swan Creek oil field, Tennessee. The one index map that is not shown is the areal extent of the shale gas plays in the basin. The extents of the plays can be found in Coleman and others (this volume, chap. G.13).

Appalachian basin↗

Assessment of Appalachian basin oil and gas resources: Devonian gas shales of the Devonian Shale-Middle and Upper Paleozoic Total Petroleum System

This report presents the results of a U.S. Geological Survey (USGS) assessment of the technically recoverable undiscovered natural gas resources in Devonian shale in the Appalachian Basin Petroleum Province of the eastern United States. These results are part of the USGS assessment in 2002 of the technically recoverable undiscovered oil and gas resources of the province. This report does not use the results of a 2011 USGS assessment of the Devonian Marcellus Shale because the area considered in the 2011 assessment is much greater than the area of the Marcellus Shale described in this report. The USGS assessment in 2002 was based on the identification of six total petroleum systems, which include strata that range in age from Cambrian to Pennsylvanian. The Devonian gas shales described in this report are within the Devonian Shale-Middle and Upper Paleozoic Total Petroleum System, which extends generally from New York to Tennessee. This total petroleum system is divided into ten assessment units (plays), four of which are classified as conventional and six as continuous. The Devonian shales described in this report make up four of these continuous assessment units. The assessment results are reported as fully risked fractiles (F95, F50, F5, and the mean); the fractiles indicate the probability of recovery of the assessment amount. The products reported are oil, gas, and natural gas liquids. The mean estimates for technically recoverable undiscovered hydrocarbons in the four gas shale assessment units are 12,195.53 billion cubic feet (12.20 trillion cubic feet) of gas and 158.91 million barrels of natural gas liquids

Appalachian basin↗

Oil and gas resources of the Arctic Alaska Petroleum Province

The Arctic Alaska Petroleum Province, encompassing all the lands and adjacent Continental Shelf areas north of the Brooks Range-Herald arch, is one of the most petroleum-productive areas in the United States, having produced about 15 billion bbl of oil. Seven unitized oil fields currently contribute to production, and three additional oil fields have been unitized but are not yet producing. Most known petroleum accumulations involve structural or combination structural-stratigraphic traps related to closure along the Barrow arch, a regional basement high, which has focused regional hydrocarbon migration since Early Cretaceous time. Several oil accumulations in stratigraphic traps have been developed in recent years. In addition to three small gas fields producing for local consumption, more than 20 additional oil and gas discoveries remain undeveloped. This geologically complex region includes prospective strata within passive-margin, rift, and foreland-basin sequences. Oil and gas were generated from multiple source rocks throughout the region. Although some reservoired oils appear to be derived from a single source rock, evidence for significant mixing of hydrocarbons from multiple source rocks indicates a composite petroleum system. Both extensional and contractional tectonic structures provide ample exploration targets, and recent emphasis on stratigraphic traps has demonstrated a significant resource potential in shelf and turbidite sequences of Jurassic through Tertiary age. Recent estimates of the total mean volume of undiscovered resources in the Arctic Alaska Petroleum Province by the U.S. Geological Survey and U.S. Minerals Management Service are more than 50 billion bbl of oil and natural-gas liquids and 227 trillion ft3 of gas, distributed approximately equally between Federal offshore and combined onshore and State offshore areas.

Alaska↗

The 2008 Circum-Arctic Resource Appraisal

Professional Paper 1824 comprises 30 chapters by various U.S. Geological Survey authors, including introduction and methodology chapters, which together provide documentation of the geological basis and methodology of the 2008 Circum-Arctic Resource Appraisal, results of which were first released in August 2008. Twenty-eight chapters summarize the petroleum geology and resource potential of individual, geologically defined provinces north of the Arctic Circle, including those of northern Alaska, northern Canada, east and west Greenland, and most of Arctic Russia, as well as certain offshore areas of the north Atlantic Basin and the Polar Sea. Appendixes tabulate the input and output information used during the assessment.

Professional Paper↗

Introduction to the 2008 Circum-Arctic Resource Appraisal (CARA) professional paper

The amount of yet-to-find oil and gas in the high northern latitudes is one of the great uncertainties of future energy supply. The possibility of extensive new petroleum developments in the Arctic Ocean is of interest to the Arctic nations, to petroleum companies, and to those concerned with the delicate and changing Arctic environment. The U.S. Geological Survey (USGS) 2008 Circum-Arctic Resource Appraisal (CARA) had the express purpose of conducting a geologically based assessment of undiscovered petroleum north of the Arctic Circle, thereby providing an initial evaluation of resource potential.

Professional Paper↗

Geology and assessment of undiscovered oil and gas resources of the Lomonosov-Makarov Province, 2008

The Lomonosov-Makarov Province lies in the central Arctic Ocean and encompasses the northern part of the oceanic Amerasia Basin (Makarov and Podvodnikov Basins) and the adjoining Lomonosov Ridge and Siberian continental margins. The Amerasia Basin is thought to have been created in the Jurassic and Early Cretaceous by rotational rifting of the Alaska-Siberia margin away from the Canada margin about a pivot point in the Mackenzie Delta and an associated continental-scale transform fault along the Lomonosov Ridge. The province is bounded on the south by the Cretaceous Alpha-Mendeleev Ridge, an undersea ridge composed of plume-type volcanic rocks that obliquely crosses the Amerasia Basin, dividing it into northern and southern parts. The thickest passive-margin succession in the province lies along the Siberian margin, where sediments thin from a maximum thickness along the continental margin to less than 2 km in the basin. The northern part of the province consists of the Lomonosov Ridge, which was rifted away from the Eurasia Plate in the Paleocene during formation of the oceanic Eurasia Basin, creating an isolated, narrow, submerged, but high-standing microcontinent. This part of the province contains sediments that were shed from the Eurasia Plate in the Mesozoic and covered by pelagic and hemipelagic sediments in the Cenozoic, creating depositional successions with thicknesses ranging from about 1 to more than 5 km. This tectonic framework provides the basis for division of the province into four assessment units (AUs), including (1) Lomonosov Ridge AU, (2) Makarov Basin Margin AU, (3) Siberian Passive Margin AU, and (4) Makarov Basin AU. The Lomonosov Ridge and Makarov Basin Margin AUs compose a displaced part of the Cretaceous shelf and slope, respectively, of the Eurasia continental margin with a covering drape of pelagic Cenozoic sediments. The Siberian Passive Margin and Makarov Basin AUs represent the slope of the Siberian continental margin and adjoining basin plain deposits, respectively, deposited on oceanic crust of the northern Amerasia Basin. All of the AUs are entirely submarine and covered by the polar icecap, and consequently have not been explored for petroleum. Petroleum source rock units considered in the assessment of the province are mostly hypothetical, and include Triassic and Jurassic platformal marine shale units on the Lomonosov Ridge, and province-wide Lower Cretaceous synrift, Lower and Upper Cretaceous postrift, and Paleogene organic-rich shale intervals. The most prospective reservoirs and traps are envisioned to include base-of-slope turbidite-fan complexes, slope channels and basins, extensional and growth fault structures, and other stratigraphic, structural, and composite trap features typically present on clastic-dominated continental passive margins. Because of concerns about reservoir quality in the Makarov Basin AU and the detrimental effect of Paleocene rifting in the Lomonosov Ridge AU, these units were not quantitatively assessed, as they were judged to have less than 10 percent probability of containing at least one accumulation of hydrocarbons equal to or greater than 50 million barrels of oil equivalent (MMBOE). The mean volumes of undiscovered resources for the Makarov Basin Margin AU are estimated to be 0.12 billion barrels of oil and 0.74 trillion cubic feet of nonassociated gas, whereas the undiscovered resources for the Siberian Passive Margin AU are estimated to be ~1 billion barrels of oil and 4.7 trillion cubic feet of nonassociated gas.

Professional Paper↗