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fuels for millions of acres of public lands and for annually monitoring fire fuel conditions.

A geologically referenced computer file was developed containing terrain information, road network, ownership, and advanced very high resolution radiometer data acquired on six dates in March and April 1982 (during the spring growth cycle of the grasslands). These data were processed to compute an index related to the greenness of vegetation. Bureau of Land Management personnel used resulting greenness images to monitor the spring growth patterns and the date of grassland maturation.

A wildland fire fuels map with 13 categories was produced from the previously collected advanced very high resolution radiometer data, digital terrain data, and Bureau of Land Management information on the area. This fuel map is being used by fire management officers as a base map for fire planning, and advanced very high resolution radiometer data have proved useful for mapping and monitoring wildland fire fuels for the Bureau of Land Management's National Wildfire Management Program.

Geologic Investigations

Mission and Outlook

During fiscal year 1983, the Geologic Division continued its programs to assess energy and mineral resources onshore and offshore, to identify and investigate geologic hazards, and to evaluate the Nation's geologic framework, the geologic processes that have shaped it, and their relationship to long-term climatic changes.

The articles in this section of the Yearbook describe some of the most significant accomplishments of the Geologic Division during fiscal year 1983. We believe that these articles, while representing only a select few of the activities of the Division, show how geologic research simultaneously opens new avenues in geoscience and provides the basic information to conduct missions that are central to the national welfare.

caused more than $200 million in property losses. The Coalinga earthquake demonstrated again the vulnerability of unreinforced masonry buildings in the United States to damaging earthquake ground motion. Survey earthquake specialists, studying strong ground motion accompanying the Coalinga event and similar data from the 1979 Imperial Valley, California, earthquake, produced mathematical formulae that permit the prediction of damaging earthquake ground motion. Efforts to accurately forecast potentially damaging earthquakes in California continued with the calculation of probabilities for earthquakes in each of the several parts of the San Andreas fault system. The first set of comprehensive earthquake ground-shaking hazards maps for interval times of 10, 50, and 250 years were published for the conterminous United States. In 1983, Survey geologists and seismologists also drew national attention to the potential for damaging earthquakes in the Eastern United States, for identifying buried active faults in the central Mississippi Valley which were probably responsible for the great New Madrid, Missouri, earthquakes of 1811-12, and for recognizing the possibility that tremors like the Charleston, South Carolina, earthquake of 1886 might occur elsewhere along the eastern seaboard.

Major Programs

The Geologic Division program is presented to Congress under five major program headings. A discussion of accomplishments under these subactivities during this last fiscal year follows:

Geologic Hazards Surveys

Land Resource Surveys

The eruption of Kilauea Volcano in Hawaii, catastrophic landslides in Utah and California, and a damaging magnitude 6.5 earthquake near Coalinga, California, focused attention in 1983 on the Survey's Geologic Hazards programs. In 1983, U.S. Geologic Survey volcanologists and seismologists accurately predicted the reawakening of Hawaii's Kilauea volcano; successfully forecast the continuing eruptions of the State of Washington's Mount St. Helens; and monitored seismic activity and ground deformation that may portend potential volcanic activity at Long Valley, California, and Mauna Loa Volcano, Hawaii. Survey landslide experts responded to an emergency request from the State of Utah to help identify and mitigate potentially damaging landslides triggered by rapid melting of a record mountain snowpack and locally heavy spring rains. One landslide near Thistle, Utah, alone

During fiscal year 1983, research within the varied tasks of the Geologic Framework Program contributed significantly towards advancing our understanding of the fundamental geologic framework of the Nation and the nature of the geologic processes that have shaped it. Multidisciplinary studies along geologic transects that cross major portions of the continent have added greatly to the achievement of these objectives. Research on the rapidly developing accreted terrane concept, wherein the margin of North America was formed by the welding together of many microcontinents, contributes to and depends upon results from the transect studies. These

during fiscal year 1983. New remote sensing techniques were developed to delineate zones of altered rocks associated with ore deposits. Genetic models of epithermal gold-alunite ore deposits and a number of new exploration techniques to aid in the conduct of mineral resource assessment activities also were developed. A prototype International Strategic Mineral Inventory of worldwide major mines and deposits of chromium, nickel, manganese, and phosphate was completed in cooperation with the Bureau of Mines and representatives of Canada, West Germany, Australia, and South Africa.

studies, together with research on igneous terranes, geologic processes, the ages of rocks, and the Precambrian core of the United States, continue to produce numerous maps and reports that not only increase the body of scientific knowledge of the Nation's geologic framework but have immediate applied uses. These uses are particularly evident in evaluating the Nation's energy and mineral resources and in identifying and understanding geologic hazards. Studies conducted under the Climate Program are progressing towards understanding the natural climatic history of the Earth. These studies provide the basis for assessing the effects of man's activities on long- and short-term changes in global climate. In response to the President's Caribbean Basin Initiative, geologic investigations have been initiated in that region. These studies will contribute to the economic and political health of the Caribbean Basin countries in addition to advancing knowledge of the important geologic relationships between that region and the North American continent. The Geologic Division will continue to place heavy emphasis on basic geologic research capabilities because of the importance not only to the Division's other programs but also to the Nation and a large and growing user community.

Energy Geologic Surveys

Mineral Resource Surveys

During fiscal year 1983, the Geologic Division completed the 20-year program conducted jointly with the Bureau of Mines to assess the mineral resource potential of National Forest lands being considered by Congress for designation as Wilderness Areas. The results of those investigations were compiled in a two-volume professional paper entitled Wilderness Mineral Potential, which discusses nearly 800 study areas. (Publication of this book is scheduled for early in fiscal year 1984.) Significant advances were also made in the analogous program which is being conducted by the Bureau of Mines and Geologic Division on behalf of the Bureau of Land Management. In addition, the Division completed mineral resource assessments in Montana, Idaho, and Utah under the Conterminous United States Mineral Appraisal Program.

The Division made great strides in other significant mineral-related research projects

During fiscal year 1983, the Geologic Division completed an assessment of undiscovered potential oil and gas resources in all categories of Wilderness or designated Wilderness Study Lands in 11 Western States. Digital cartographic techniques were used by the National Mapping Division to produce base maps and to combine sets of geologic and geographic data for the final assessment products. Planning to provide similar assessments of oil, gas, and coal for all categories of federally owned land is underway; the actual work will begin in fiscal year 1984. Research and development continued toward the production of a major information base to be called the National Oil and Gas Information Atlas.

A major compendium of research papers summarizing many years of uranium studies in the Jurassic rocks of the San Juan Basin, New Mexico, was completed and prepared for publication. These studies included regional stratigraphic and sedimentologic work, compilations and interpretations of huge amounts of subsurface data, geochemical and petrographic examination into the processes of ore formation, geophysical surveys, and a new geostatistical approach to resource assessment.

Coal geologists of the Geologic Division continued to provide information on the geology, quantity, and quality of coal in support of the Department of the Interior's coal-leasing program for Federal lands. A total of 12 quadrangle folios was completed; these will be added to the growing base of information used in land use planning and lease-program management. The data, together with other information from


cooperating State geological surveys, further improved the capability of the National Coal Resources Data System.

Offshore Geologic Surveys

In fiscal year 1983, the Geologic Division provided substantial information in support of the decision process that led to the Presidential proclamation of the ''Exclusive Economic Zone' on March 10, 1983. A discussion of progress to date and projected future activities is provided in an essay on marine research in the ''Perspectives' section of this volume. Survey scientists gathered new seafloor photographs and geological samples of the area around the polymetallic sulfide vents at the southern end of the Juan de Fuca Ridge.

Sampling of the sulfide deposits, previously done from the surface, was attempted on the seafloor by a joint U.S. Geological Survey-Geological Survey of Canada group using a special core drill developed in Canada. A side-scan sonar survey was conducted to obtain sea floor images of the Juan de Fuca and Gorda Ridges; this survey has added greatly to the understanding of the geology of these ocean spreading centers and the likely distribution of their sulfide resources. Near the end of the year, the Research Vessel Samuel P. Lee embarked on "Operation Deep Sweep," a research cruise covering geologic framework, process, and resource surveys in the Arctic and Central and South Pacific Oceans, and the waters around Antarctica.

Petroleum Potential of Wilderness Lands in the Western United States

National concerns over sources for continuing energy supplies within the United States have generated a great deal of interest in the last few years with respect to the probable occurrence of energy and nonenergy resources on Federal lands that have limited access for exploration and development. As a part of the U.S. Geological Survey's continuing efforts to inventory the energy resources on Federal lands, a special investigation was conducted to assess the potential oil and gas resources occurring in the designated and proposed Wilderness Lands in the Western United States.

To properly assess the petroleum potential of these lands, petroleum geologists in the Survey conducted systematic studies that were based on the available geological and geophysical information to determine the geologic favorability for the occurrence or lack of petroleum resources in these Wilderness Lands.

The scope of the investigation is limited to conventional petroleum resources occurring in the Wilderness Lands administered by the Bureau of Land Management, the U.S. Forest Service, the National Park Service, and the U.S. Fish and Wildlife Service. The total area of the study covers nearly 74 million acres of Wilderness Lands in Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington, and Wyoming.

This investigation is unique in that it is the first Federal program to conduct systematic geologic studies of the petroleum resource potential on specifically designated Federal lands and to integrate all the available information concerning these lands through the use of a computer-based digital cartographic data system. Map data portraying the boundaries of the Wilderness Lands, the terrane and underlying geologic structure, and previously delineated petroleum resource provinces have been digitized and correlated by using computer techniques. These data, when merged with data from wells drilled and from petroleum production on adjoining lands, enable the geologists to conduct a systematic study of each wilderness tract.

An analysis of all the geologic characteristics favorable or unfavorable for petroleum occurrence in conjunction with the geologic settings for the Wilderness Lands in the western 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 oil or gas shows or actual production, and the presence of favorable sedimentary rock sections underlying volcanic terrane or faulted and overthrust areas.

The assessments of the petroleum resources on Wilderness Lands were both qualitative and quantitative. Each tract was assigned a qualitative rating describing the potential for the favorable occurrence of recoverable oil and gas resources, such as high, medium, low, low to zero, zero or unknown potential. The quantitative assessment was subjectively estimated based on the richness and the potential of the wilderness tracts relative to the total petroleum potential for the respective basin or province within which they occurred.

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 reported for the Wilderness Lands by State and for the total Wilderness Lands in the 11 Western States. At least 34 percent of the total acreage for Wilderness Lands, or approximately 25 million acres, has the geologic characteristics necessary for the occurrence of petroleum resources in varying amounts. 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 which 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

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