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USGS2014

Appendix B—The work of the Geological Survey and cooperating state agencies on ground water for war purposes

The very large service which the geologists and engineers trained in ground‐water hydrology are rendering in this country in the prosecution of the war is due largely to the effective organization for this purpose. The Federal agency in which this service centers is the Water Resources Branch of the United States Geological Survey. The Ground Water Division of this branch has a technical personnel of nearly 100 geologists, engineers, and physicists, and its work is supported by the chemists of the Quality of Water Division and the engineers of the other Divisions of the Branch. It functions through a central office in Washington and 25 widely distributed field‐offices. Moreover, this service is effectively supported by the State Geological surveys, State Engineer offices, and other State agencies concerned with water‐resources, not only in the 34 States in which there is formal cooperation with the Federal Geological Survey in ground‐water investigations but also in those States in which there are no formal cooperative agreements. The magnitude of the civilian service rendered is indicated by the fact that to date about 1,600 reports on water‐supplies from wells have been made to the War and Navy Departments and other war agencies by the Geological Survey and cooperating State organizations.

Article↗
USGS2014

Contaminants from Cretaceous black shale: II. Effect of geology, weathering, climate, and land use on salinity and selenium cycling, Mancos Shale landscapes, southwestern United States

The Cretaceous Mancos Shale (MS) is a known nonpoint source for a significant portion of the salinity and selenium (Se) loads in the Colorado River in the southwestern United States and northwestern corner of Mexico. These two contaminants pose a serious threat to rivers in these arid regions where water supplies are especially critical. Tuttle et al. (companion paper) investigates the cycling of contaminants in a Colorado River tributary watershed (Uncompahgre River, southwestern Colorado) where the MS weathers under natural conditions. This paper builds on those results and uses regional soil data in the same watershed to investigate the impact of MS geology, weathering intensity, land use, and climate on salt and Se storage in and flux from soils on the natural landscape, irrigated agriculture fields, areas undergoing urban development, and wetlands. The size of salinity and Se reservoirs in the MS soils is quantified. Flux calculations show that during modern weathering, natural landscapes cycle salt and Se; however, little of it is released for transport to the Uncompahgre River (10% of the annual salinity and 6% of the annual Se river loads). When irrigated, salinity and Se loads from the MS soil increase (26% and 57% of the river load, respectively), causing the river to be out of compliance with Federal and State Se standards. During 100 years of irrigation, seven times more Se has been removed from agricultural soil than what was lost from natural landscapes during the entire period of pedogenesis. Under more arid conditions, even less salt and Se are expected to be transported from the natural landscape. However, if wetter climates prevail, transport could increase dramatically due to storage of soluble phases in the non-irrigated soil. These results are critical input for water-resource and land-use managers who must decide whether or not the salinity and Se in a watershed can be managed, what sustainable mitigation strategies are possible, and what landscapes should be targeted. The broader implications include providing a reliable approach for quantifying nonpoint-source contamination from MS and other rock units elsewhere that weather under similar conditions and, together with results from our companion paper, address the complex interplay of geology, weathering, climate, and land use on contaminant cycling in the arid Southwest.

Colorado↗
USGS1980

Water resources investigations in New York, 1980

This report describes the water-resources investigations conducted by the U.S. Geological Survey in New York in 1980; many of these studies will continue into 1981 or longer. The Geological Survey began its water-resources studies in New York State in 1895 with a stream-gaging program in the Catskill Mountain region and entered its first cooperative program, with the Office of the State Engineer, in 1900. Since 1910, the Survey has maintained a District office in Albany to direct its water investigations within the State. A Long Island subdistrict office was established in 1932 to monitor and study the ground-water situation in this area of increasing urbanization. Subdistrict offices are also maintained in Ithaca and Albany to collect and interpret data from western and eastern New York, respectively. A field station is maintained in Potsdam to collect records in the northernmost part of the State. A bibliography of reports published or released in 1980 by the New York District is included. (USGS)

Open-File Report↗
USGS2014

Desert wetlands in the geologic record

Desert wetlands support flora and fauna in a variety of hydrologic settings, including seeps, springs, marshes, wet meadows, ponds, and spring pools. Over time, eolian, alluvial, and fluvial sediments become trapped in these settings by a combination of wet ground conditions and dense plant cover. The result is a unique combination of clastic sediments, chemical precipitates, and organic matter that is preserved in the geologic record as ground-water discharge (GWD) deposits. GWD deposits contain information on the timing and magnitude of past changes in water-table levels and, therefore, are a potential source of paleohydrologic and paleoclimatic information. In addition, they can be important archeological and paleontological archives because desert wetlands provide reliable sources of fresh water, and thus act as focal points for human and faunal activities, in some of the world's harshest and driest lands. Here, we review some of the physical, sedimentological, and geochemical characteristics common to GWD deposits, and provide a contextual framework that researchers can use to identify and interpret geologic deposits associated with desert wetlands. We discuss several lines of evidence used to differentiate GWD deposits from lake deposits (they are commonly confused), and examine how various types of microbiota and depositional facies aid in reconstructing past environmental and hydrologic conditions. We also review how late Quaternary GWD deposits are dated, as well as methods used to investigate desert wetlands deeper in geologic time. We end by evaluating the strengths and limitations of hydrologic and climatic records derived from GWD deposits, and suggest several avenues of potential future research to further develop and utilize these unique and complex systems.

Earth-Science Reviews↗
USGS1946

Geology and nickel mineralization of the Julian-Cuyamaca area, San Diego County, California

The Julian-Cuyamaca area is in the San Diego Mountains, one of the Peninsular Ranges of southern California. It lies in San Diego County, about 3 miles south of Julian, and approximately 60 miles northeast of San Diego. The area was mapped, and its nickel mineralization studied, from March to June, 1944; the work was part of the U. S. Geological Survey's program of strategic mineral investigations.

California↗
USGS2007

Publications of the Western Earth Surfaces Processes Team 2005

Introduction The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping, earth-surface process investigations, and related topical earth science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2005 included southern California, the San Francisco Bay region, the Mojave Desert, the Colorado Plateau region of northern Arizona, and the Pacific Northwest. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. The results of research conducted by the WESPT are released to the public as a variety of databases, maps, text reports, and abstracts, both through the internal publication system of the USGS and in diverse external publications such as scientific journals and books. This report lists publications of the WESPT released in 2005 as well as additional 2002, 2003, and 2004 publications that were not included in the previous lists (USGS Open-File Reports 03-363, 2004- 1267, 2005-1362). Most of the publications listed were authored or coauthored by WESPT staff. The list also includes some publications authored by non-USGS cooperators with the WESPT, as well as some authored by USGS staff outside the WESPT in cooperation with WESPT projects. Several of the publications listed are available on the World Wide Web; for these, URL addresses are provided. Many of these web publications are USGS Open-File reports that contain large digital databases of geologic map and related information. Information on ordering USGS publications can be found on the World Wide Web at http://www.usgs.gov/pubprod/, or by calling 1-888-ASK-USGS. The U.S. Geological Survey's web server for geologic information in the western United States is located at http://geology.wr.usgs.gov/. More information is available about the WESPT is available on-line at http://geology.wr.usgs.gov/wgmt.

Open-File Report↗
USGS2007

Publications of the Western Earth Surface Processes Team 2006

The Western Earth Surface Processes Team (WESPT) of the U.S. Geological Survey (USGS) conducts geologic mapping, earth-surface process investigations, and related topical earth science studies in the western United States. This work is focused on areas where modern geologic maps and associated earth-science data are needed to address key societal and environmental issues such as ground-water quality, landslides and other potential geologic hazards, and land-use decisions. Areas of primary emphasis in 2006 included southern California, the San Francisco Bay region, the Mojave Desert, the Colorado Plateau region of northern Arizona, and the Pacific Northwest. The team has its headquarters in Menlo Park, California, and maintains smaller field offices at several other locations in the western United States. This compilation gives the bibliographical citations for 123 new publications, most of which are available online using the hyperlinks provided.

Open-File Report↗
USGS2007

Identification, prediction, and mitigation of sinkhole hazards in evaporite karst areas

Sinkholes usually have a higher probability of occurrence and a greater genetic diversity in evaporite terrains than in carbonate karst areas. This is because evaporites have a higher solubility and, commonly, a lower mechanical strength. Subsidence damage resulting from evaporite dissolution generates substantial losses throughout the world, but the causes are only well understood in a few areas. To deal with these hazards, a phased approach is needed for sinkhole identification, investigation, prediction, and mitigation. Identification techniques include field surveys and geomorphological mapping combined with accounts from local people and historical sources. Detailed sinkhole maps can be constructed from sequential historical maps, recent topographical maps, and digital elevation models (DEMs) complemented with building-damage surveying, remote sensing, and high-resolution geodetic surveys. On a more detailed level, information from exposed paleosubsidence features (paleokarst), speleological explorations, geophysical investigations, trenching, dating techniques, and boreholes may help in investigating dissolution and subsidence features. Information on the hydrogeological pathways including caves, springs, and swallow holes are particularly important especially when corroborated by tracer tests. These diverse data sources make a valuable database-the karst inventory. From this dataset, sinkhole susceptibility zonations (relative probability) may be produced based on the spatial distribution of the features and good knowledge of the local geology. Sinkhole distribution can be investigated by spatial distribution analysis techniques including studies of preferential elongation, alignment, and nearest neighbor analysis. More objective susceptibility models may be obtained by analyzing the statistical relationships between the known sinkholes and the conditioning factors. Chronological information on sinkhole formation is required to estimate the probability of occurrence of sinkholes (number of sinkholes/km2 year). Such spatial and temporal predictions, frequently derived from limited records and based on the assumption that past sinkhole activity may be extrapolated to the future, are non-corroborated hypotheses. Validation methods allow us to assess the predictive capability of the susceptibility maps and to transform them into probability maps. Avoiding the most hazardous areas by preventive planning is the safest strategy for development in sinkhole-prone areas. Corrective measures could be applied to reduce the dissolution activity and subsidence processes. A more practical solution for safe development is to reduce the vulnerability of the structures by using subsidence-proof designs. ?? 2007 Springer-Verlag.

Conference Paper↗
USGS1990

Base-flow investigation on the Sacramento River, September 25, 1985, near Sunspot, Otero County, New Mexico

On September 25, 1985, the U.S. Geological Survey conducted a base-flow investigation to better define the surface-water resources of the Sacramento River drainage basin in Otero County , south-central New Mexico. The investigation included all flow in the Sacramento River from the initial point of flow to the point of zero flow 20.1 river miles downstream. A total of 12 discharge measurements, 3 observations of zero flow and 2 observations of initial flow were obtained during this investigation. Discharge measurements and observations showed a general increase in discharge from river mile 22.4 to a discharge of 6.69 cu ft/sec at river mile 8.4. Discharge then decreased from river mile 8.4 to zero flow at river mile 3.3. Specific conductance and water temperature also were taken concurrently with the discharge measurements. Specific conductance of water generally decreased in a downstream direction from 600 microsiemens/cm at 25 C at river mile 21.9 to 330 microsiemens/cm at 25C at river mile 4.6. (USGS)

Open-File Report↗
USGS1960

Ground-water data for Fairbanks area, Alaska

A compilation of records of about 450 wells in the Fairbanks area is presented herein. The data were collected by D. J. Cedarstrom and Troy L. Pewe during the first phases of an investigation by the United States Geological Survey of the permafrost, terrain, and water resources of the Fairbanks area. The enclosed map of the area, showing well locations, was prepared by the Regional Sanitary Engineer, Sanitation and Engineering, Alaska Department of Health and Welfare. The data were released to the Survey's open file in 1948, but are reproduced in the Alaska Department of Health and Welfare Hydrological Data series to insure preservation. Where known, the data include for each well the names of the owner and driller; the depth of the well; the depth to the top and bottom of permafrost; and the reported quality of water. The well records and location may be very useful for future subsurface investigations or construction. The well location map was based on the Fairbanks street names as of 1948. Since that time, many of the street names and the numbering system have changed. Hence, the reader should not refer to the address of a particular well, but to the well number when locating a well on the map. The Geological Survey has recompiled the well data in the Fairbanks area for its final phase of a ground-water study. Data through 1954 is to be presented in a Water-Supply Paper now in preparation. Pertinent portions of the enclosed well data will be presented in the forthcoming report. Some of the enclosed well data, and additional well logs, have been published in a report (Pewe, Troy L., 1958, Geology of the Fairbanks (D-2) quadrangle, Alaska: U. S. Geological Survey GQ 110) describing the geology and subsurface conditions in the area.

Alaska↗
USGS1994

National Water-Quality Assessment (NAWQA) Program, Long Island-New Jersey (LINJ) Coastal Drainages Study Unit : Scope of the Long Island-New Jersey Coastal Drainages Study-Unit investigation

Scope of the Long Island-New Jersey Coastal Drainages Study-Unit Investigation In 1991, the U.S. Geological Survey (USGS) began a National Water-Quality Assessment (NAWQA) Program to document the status of and trends in quality of a large representative part of the Nation's water resources and to provide a sound scientific understanding of the primary natural and human factors that affect the quality of these resources. The program is designed to produce long-term, consistent water-quality information that will be useful to policymakers and managers at national, State, and local levels. Investigations of 60 hydrologic systems (study units), which include parts of most major river basins and aquifer systems in the United States, are the building blocks of NAWQA. A framework has been established to ensure nationwide consistency in the approach to each study--in field and laboratory methods, in water-quality measurements, and in the supporting data requirements. Twenty studies were started in 1991, 20 more have begun in 1994, and 20 are scheduled to begin in 1997. A major design feature of the program that will facilitate integration of water-quality information at national, regional, and local scales is coordination between the individual study-unit teams and the national synthesis effort at all stages of the investigations. Thus, results that relate to various topics addressed in the study-unit investigations will be integrated smoothly into NAWQA's national synthesis component. Teams have been developed to address the following topics of national importance: pesticides, nutrients, and volatile organic compounds. These teams are investigating the specific issues by means of comparative studies of a large set of hydrologic systems distributed over a wide range of environmental settings found in the 60 study-units. The information below summarizes the goals and scope of the NAWQA Program and the Long Island-New Jersey Coastal Drainages study, which began in 1994.

New Jersey↗
USGS1981

Environmental geologic studies on the southeastern United States Atlantic Outer Continental Shelf, 1977-1978

This report is a summary of the second year of marine environmental research activities by the U.S. Geological Survey (USGS) on the southeaster U.S. Atlantic Continental Margin, in accordance with with Memorandum of Understanding (MOU) AA551-MU8-13 between the USGS and the Bureau of Land Management (BLM). The report covers studies whose fieldwork was conducted during the period from 1 October 1977 to 30 September 1978. The results of the first year of study are reported in Popenoe (1978a and b) and as U.S. Department of Commerce NTIS report PB 300-820. The purpose of these investigations is to provide basic geologic and oceanographic data to the BLM Outer Continental Shelf (OCS) Marine Environmental Studies Program in support of management decisions which relate to possible development of oil and gas resources of the continental shelf. The objectives of the USGS-BLM geologic research program for fiscal year 1978 (FY-78) were 1) to determine the sedimentation rates and processes on the upper slope and inner Blake Plateau; 2) to determine the distribution, areal extent, and vertical characteristics of geological features supportive of biological communities; 3) to monitor the transport of bottom sediment across the OCS, evaluate its possible effect on pollutant transfer along the seabed and the potential of sediment as a pollutant sink, determine the implications of erosion/deposition on pipeline emplacement, and aid the interpretation of chemical, biological, and physical data; 4) to determine the concentration levels of chosen trace metals and silica in three chemically defined fractions of the suspended particulate matter (seston); 5) to study the shelf edge and slope near areas of oil and gas interest, and the northern portion of the Blake Plateau for evidence of slope instability and other geologic hazards, and 6) to determine the depth and rate of sediment mixing caused by large storms and/or by benthic organisms and where possible to estimate the rate of active sediment accumulation.

Atlantic Outer Continental Shelf↗
USGS1994

Summary of water-resources activities of the U.S. Geological Survey in Colorado - Fiscal years 1992-93

Water-resources activities of the U.S. Geological Survey in Colorado consist of collecting water-resources data and doing interpretive hydrologic investigations. The water-resources data and the results of the investigations are published or released by either the U.S. Geological Survey or by cooperating agencies. Water-resources investigations in Colorado for the 1992-93 fiscal years (October 1,1991, to September 30,1993) are described in this report.

Colorado↗
USGS2000

Delineation of groundwater recharge areas, western Cape Cod, Massachusetts

The unconfined sand-and-gravel aquifer in western Cape Cod, Massachusetts, which is the sole source of water supply for the communities in the area, is recharged primarily from precipitation. The rate of recharge from precipitation is estimated to be about 26 inches per year (in/yr), or about 60 percent of the precipitation rate. This recharge rate yields a flow through the aquifer of about 180 million gallons per day (Mgal/d). Groundwater flows radially outward from the top of the water-table mound in the north-central part of the flow system toward the coast, as indicated by the water-table contours on the large map on this sheet. Recharge that reaches the water table near the top of the mound travels deeper through the aquifer than recharge that reaches the water table closer to the coast. All recharge to the aquifer ultimately discharges to pumping wells, streams, or coastal areas; however, some of this recharge may flow first through kettle ponds before eventually reaching these discharge points. Continued land development and population growth on western Cape Cod, and activities related to the operation of the Massachusetts Military Reservation (MMR), have created concerns regarding the supply of potable water in western Cape Cod and the quality and quantity of water discharging to ponds, streams, and coastal areas. Recent investigations estimated the future demand for drinking water in western Cape Cod, as well as the areas that contribute water to existing and proposed public-supply wells. Determining the source of freshwater that discharges to ponds, streams, and coastal areas is of critical importance in the protection of these natural resources for the communities of western Cape Cod. The purpose of this report is to illustrate concepts of ground-water recharge areas under average pumping and recharge conditions. This report presents results of an investigation conducted by the U.S. Geological Survey (USGS), in cooperation with the Air Force Center for Environmental Excellence (AFCEE), to delineate the areas that contribute recharge to public-supply wells, ponds, streams, and coastal areas on western Cape Cod for average annual pumping and recharge rates for the period of 1994–1996. The time period of 1994–1996 was selected for this analysis because it represents the average stress conditions prior to large-scale pumping, treatment, and reinjection of water from the MMR Installation Restoration Program's ground-water remediation systems. The pumping and reinjection of large amounts of water from these remediation systems would complicate greatly the delineation of ground-water recharge areas and therefore is beyond the scope of this analysis. The Chemical Spill-4 plume-containment system, however, is included in the simulation since it has been operating since 1993 and has been pumping, treating, and reinjecting only about 0.2 Mgal/d of water. Since 1996, however, AFCEE has constructed remediation systems for seven additional contaminant plumes that are not included in this analysis. Currently (1999), these systems are pumping, treating, and reinjecting about 9.7 Mgal/d. By 2002, when all of these systems, including those being designed, are expected to be operating, it is estimated that they will be pumping, treating, and reinjecting as much as 15.6 Mgal/d of water in the western Cape Cod aquifer. For additional information on the hydrology and geology of western Cape Cod, the reader is referred to the following reports: LeBlanc and others (1986), Barlow and Hess (1993), Masterson and others (1997a), Masterson and others (1997b), Masterson and others (1998), Ogden Environmental and Energy Services, Inc. (1998) and Jacobs Engineering Group, Inc. (1999).

Massachusetts↗
USGS2014

Magnetic studies of the Florida peninsula

This investigation was undertaken primarily as a pilot‐experiment for gaining information concerning the field‐technique and accuracy which is needed for covering large areas in detail and at the same time economically. Owing to the complex nature of magnetic observations, such a pilot‐study serves, in addition, as a basis for determining the best methods of presenting the results of large areal studies in an easily comprehensible form. The State of Florida was chosen for such preliminary study for the following reasons: First, because it is geologically ideal for such an investigation since it comprises a series of unconsolidated, flat‐lying, Tertiary and Cretaceous sediments of low magnetic permeability covering a complex and much‐folded crystalline basement composed largely of rocks carrying strongly paramagnetic materials; secondly, because information concerning the structural trends of the crystalline basement would be of great interest and importance in the study of Appalachian orogeny and the relationship of the Florida Peninsula to both the Appalachian and Antillean tectonic systems.

Florida↗
USGS1946

Summary of the Midway and Wilcox stratigraphy of Alabama and Mississippi

This study of the stratigraphy of the Midway and Wilcox groups of Alabama and Mississippi was part of the extensive bauxite investigations carried on by the Geological Survey and the Bureau of 'lines of the United States Department of the Interior in 19112 and 1943. The stratigraphic study was undertaken to determine in what formation or formations the bauxite deposits occur, under what paleogeographic conditions the bauxite-bearing formations were deposited, and when and under what conditions the bauxite was formed.

Alabama, Mississippi↗
USGS2007

Ecological Investigations of the Federally Endangered Shivwits Milk-Vetch (Astragalus ampullarioides)--2006 Annual Report

Astragalus ampullarioides (Welsh) Welsh, the Shivwits milk-vetch, is an herbaceous perennial legume that was listed as federally endangered in September 2001. Known populations of this edaphic endemic species are restricted to Washington County, Utah, with the majority of occurrences found on gently sloping outcrops of the Triassic Petrified Forest Member of the Chinle Formation at the edge of the Mojave Desert. At the time of listing in 2001, surveys estimated a total of 1000 individuals for the species. In April-May 2006, surveys estimated approximately 4205 individuals distributed among six populations. Of the total number of individuals estimated in spring 2006, over 75 percent were distributed among three subpopulations in Zion National Park and approximately 60 percent occurred at a single 0.3-ha site in the Park. In addition to small population sizes and limited geographic distributions, the species is threatened to varying degrees by urbanization, livestock grazing, off-road vehicle use, and invasive exotic plants. In April 2006, the U.S. Geological Survey (USGS) initiated ecological investigations of the Shivwits milk-vetch to support conservation management and recovery of the species by the National Park Service (NPS; Zion National Park), the U.S. Fish and Wildlife Service (USFWS), the Bureau of Land Management (BLM), the Shivwits Band of the Paiute Tribe, and other cooperators such as The Nature Conservancy of Utah (TNC). To date, funding for this research has been provided by the Southwest Biological Science Center of the USGS Biological Resources Discipline, the USGS-NPS Park-Oriented Biological Support Project, and the Earth Surface Dynamics Program of the USGS Geologic Discipline. Additional logistical support has been provided by the Bureau of Land Management, Grand Staircase-Escalante National Monument. General objectives of this research are (1) to develop a better understanding of species-environment relations to support habitat modelling, future surveys for additional recovery populations, and potential efforts to establish new recovery populations; and (2) to evaluate effects of invasive exotic plants on habitat conditions and measures of milk-vetch performance. Specific objectives are to: Describe the distribution and abundance of milk-vetch populations and associated invasive exotic plant species within and outside of Zion National Park (Zion NP) in relation to geologic / geomorphic setting, soil properties, and plant community composition. In a field setting in Zion NP, conduct experiments to evaluate effects of invasive exotic plants on reproductive output and seedling establishment of A. ampullarioides across a gradient of exotic species biomass. Conduct greenhouse studies and analyze soils to evaluate effects of invasive exotic plants on soil biological properties (including mycorrhizal inocculation potential) that affect cycling and plant uptake of essential mineral nutrients. Based on environmental characteristics of known population locations, use Geographic Information System (GIS) tools to prepare a predictive habitat model that can be used to guide future surveys and efforts to evaluate sites for reintroduction efforts. This report describes 2006 progress and future plans for achieving these four objectives.

Open-File Report↗
USGS1983

Petroleum potential of wilderness lands in the Western United States

In 1982-83, the U.S. Geological Survey (USGS) conducted an investigation of the oil and gas potential of the designated and proposed Wilderness Lands in the Western United States. The scope of this study was limited to the assessment of conventional recoverable petroleum resources occurring in the designated and proposed Wilderness Lands of the Western United States that are administered under four Federal agencies: Bureau of Land Management (BLM), U.S. Forest Service (USFS), National Park Service (NPS), and Fish and Wildlife Service (FWS). The total area of the study included approximately 74 million acres of Wilderness Lands in these 11 Western States: Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming. The 74 million acres represent 31 percent of the total Federal lands within these 11 Western States. Approximately 49 percent of all the lands in these States are federally owned. The objective of this study was to assemble through various means all the available pertinent information that could be brought together within the USGS and integrate these data into a computer-based digital cartographic data system that was focused upon the single issue of reviewing the known geological and geophysical data to determine the geologic characteristics favorable or unfavorable for the occurrence of petroleum resources in these Wilderness Lands. In a joint effort in the USGS between the Geologic Division (GD) and the National Mapping Division (NMD) all of the mappable information used in this study was prepared and processed by using digital cartographic techniques. These include digitizing the location and boundaries of the Wilderness Lands; acreage calculations; the boundaries of the USGS petroleum provinces; and the geologic and tectonic boundaries within each petroleum province and State. In addition, searches were conducted on well data files which provided the locations and geologic information on over 5,000 wells drilled within or immediately adjacent to the Wilderness Lands. An analysis of all the geologic characteristics favorable or unfavorable for petroleum occurrence in conjunction with the geologic settings for the Wilderness Lands scattered within the framework of the petroleum provinces was performed by a team of geologists on each of the wilderness tracts. The geologic characteristics reviewed for each tract included the presence or absence of the following: adequate source beds and reservoir rocks; adequate trapping mechanisms; favorable thermal and maturation histories; presence of petroleum seeps or adjacent wells with shows or production; and the presence of favorable sedimentary rock sections underlying volcanic terrane or faulted and overthrust areas. A description of the geology and geologic framework is provided for each State along with an explanation of the interpretative geology and evaluation of the petroleum potential within the locale of each of the wilderness tracts. The assessment of the petroleum resources on the Wilderness Lands was completed in two separate stages. In the first stage the geologists evaluated the geological characteristics for the favorability or lack of favorability for the occurrence of oil and natural gas within each wilderness tract and assigned a qualitative rating for each tract's potential for the occurrence of recoverable oil and gas resources. In the second stage in evaluating the petroleum potential for the wilderness tracts, an effort was made to arrive at a quantitative assessment within the framework of the USGS's latest published resource estimates which are made on a province basis. The geologic characteristics evaluated for the favorability of petroleum occurrence within each of the clusters of wilderness tracts were the determining factors for the subjective assessments of the petroleum potential for each wilderness tract occurring within the respective basin or province. The quantitative resource assessments are subjectively determined as to the richness and potential of the wilderness tracts relative to the total petroleum potential for the respective petroleum province within which they occur. The results of the qualitative analysis of the petroleum potential of the Wilderness Lands are tabulated by total acreages for each wilderness tract as classified by its potential rating. These tabulations are made for the Wilderness Lands by petroleum province, by State, and for the total Wilderness Lands in the 11 Western States. A summary is provided of the petroleum potential by acreage for all the Wilderness Lands in the Western United States by State and for the total 11 States. At least 34 percent of the total acreage for Wilderness Lands, or approximately 25 million acres, may have the geologic characteristics necessary for the occurrence of petroleum resources in varying amounts (high, medium, and low potential). An additional 33 percent of the Wilderness Lands may have some limited potential where small sedimentary areas are mixed within igneous and metamorphic terranes, but are more likely to fall in the low to zero potential. Finally, 33 percent of the Wilderness Lands probably have no petroleum potential because they are located in terranes with predominantly igneous and (or) metamorphic rocks that are unfavorable for the occurrence of petroleum. The quantitative petroleum assessments for the Wilderness Lands in the Western United States represent a part of the total estimate of the remaining undiscovered oil and natural gas for the 38 petroleum provinces, as defined by Dolton and others in USGS Circular 860 in 1981, within which the Wilderness Lands occur. The undiscovered recoverable oil for the Wilderness Lands in the Western States is estimated to range from 0.555 to 1.490 billion barrels with a mean estimate of 0.834 billion barrels. The undiscovered recoverable natural gas is estimated to range from 5.536 to 16.639 trillion cubic feet with a mean estimate of 9. 729 trillion cubic feet. Each range corresponds to the 95 and 5 percent probabilities of more than the respective amounts. The estimates reported at the 95 percent and 5 percent probabilities and the mean estimates for oil and gas are summarized for the separate States and the aggregated totals. A series of printed maps, one for each Western State, accompanies this report (Miscellaneous Investigations Series Maps I-1537-I-1547, in press) and shows in color the location and qualitative petroleum potential of the Wilderness Lands studied, with BLM identification of tracts; the boundary locations of all major Federal and Indian lands; the boundaries and identification of the USGS petroleum provinces; and other base information. A pamphlet will accompany each State map describing the geology of the State and the local geology relative to the position of the wilderness tracts and their petroleum potential. These maps were compiled by using traditional cartographic techniques from digitally produced graphics and are published as separate sheets for each State at a scale of 1:1,000,000.

Circular↗