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At least 433 records · Page 24Linked to original sources

Digitization of a geologic map for the Quebec-Maine-Gulf of Maine global geoscience transect

The Bedrock Geologic Map of Maine was digitized and combined with digital geologic data for Quebec and the Gulf of Maine for the Quebec-Maine-Gulf of Maine Geologic Transect Project. This map is being combined with digital geophysical data to produce three-dimensional depictions of the subsurface geology and to produce cross sections of the Earth's crust. It is an essential component of a transect that stretches from the craton near Quebec City, Quebec, to the Atlantic Ocean Basin south of Georges Bank. The transect is part of the Global Geosciences Transect Project of the International Lithosphere Program. The Digital Line Graph format is used for storage of the digitized data. A coding scheme similar to that used for base category planimetric data was developed to assign numeric codes to the digitized geologic data. These codes were used to assign attributes to polygon and line features to describe rock type, age, name, tectonic setting of original deposition, mineralogy, and composition of igneous plutonic rocks, as well as faults and other linear features. The digital geologic data can be readily edited, rescaled, and reprojected. The attribute codes allow generalization and selective retrieval of the geologic features. The codes allow assignment of map colors based on age, lithology, or other attribute. The Digital Line Graph format is a general transfer format that is supported by many software vendors and is easily transferred between systems.

Circular↗

Geologic map of the Kechumstuk fault zone in the Mount Veta area, Fortymile mining district, east-central Alaska

This map was developed by the U.S. Geological Survey Mineral Resources Program to depict the fundamental geologic features for the western part of the Fortymile mining district of east-central Alaska, and to delineate the location of known bedrock mineral prospects and their relationship to rock types and structural features. This geospatial map database presents a 1:63,360-scale geologic map for the Kechumstuk fault zone and surrounding area, which lies 55 km northwest of Chicken, Alaska. The Kechumstuk fault zone is a northeast-trending zone of faults that transects the crystalline basement rocks of the Yukon-Tanana Upland of the western part of the Fortymile mining district. The crystalline basement rocks include Paleozoic metasedimentary and metaigneous rocks as well as granitoid intrusions of Triassic, Jurassic, and Cretaceous age. The geologic units represented by polygons in this dataset are based on new geologic mapping and geochronological data coupled with an interpretation of regional and new geophysical data collected by the Alaska Department of Natural Resources, Division of Geological and Geophysical Surveys. The geochronological data are reported in the accompanying geologic map text and represent new U-Pb dates on zircons collected from the igneous and metaigneous units within the map area.

Alaska↗

Reconnaissance geologic map of southwestern Misheguk Mountain quadrangle, Alaska

This map is one of a series of three reconnaissance geologic maps of the southern Misheguk Mountain quadrangle (fig. 1). Because the geology in all three map areas is similar, a composite map explanation has been designed to facilitate their combined use and provide the reader with a better perspective of the regional geology. There are some rock units and allochthons which do not occur on all three maps. For this reason, the explanation contains more rock units than occur on any one map. Rock units which appear on the accompanying map are indicated by an asterisk beside the map symbol in the explanation.

Alaska↗

Reconnaissance geologic map of south-central Misheguk Mountain Quadrangle, Alaska

This map is one of a series of three reconnaissance geologic maps of the southern Misheguk Mountain quadrangle (fig. 1). Because the geology in all three map areas is similar, a composite map explanation has been designed to facilitate their combined use and provide the reader with a better perspective of the regional geology. There are some rock units and allochthons which do not occur on all three maps. For this reason, the explanation contains more rock units than occur on any one map. Rock units which appear on the accompanying map are indicated by an asterisk beside the map symbol in the explanation.

Alaska↗

Reconnaissance geologic map of southeastern Misheguk Mountain Quadrangle, Alaska

This map is one of a series of three reconnaissance geologic maps of the southern Misheguk Mountain quadrangle (fig. 1). Because the geology in all three map areas is similar, a composite map explanation has been designed to facilitate their combined use and provide the reader with a better perspective of the regional geology. There are some rock units and allochthons which do not occur on all three maps. For this reason, the explanation contains more rock units than occur on any one map. Rock units which appear on the accompanying map are indicated by an asterisk beside the map symbol in the explanation.

Alaska↗

Explanation to accompany reconnaissance geologic map of the De Long Mountains A3, B3, and parts of A4, B4 quadrangles, Alaska

This map is one of a series of three reconnaissance geologic maps of the southern De Long Mountains quadrangle (fig. 1). Because the geology in the three map areas is similar, a composite map explanation has been designed to facilitate their combined use and give a better perspective of the regional geology. There are some rock units and allochthons which do not occur on all three maps. For this reason, the explanation contains more rock units than occur on any one map. Rock units which appear on the accompanying map are indicated by an asterisk beside the map symbol in the explanation.

Alaska↗

Reconnaissance geologic map of the De Long Mountains A2, B2, and part of C2 quadrangles, Alaska

This map is one of a series of three reconnaissance geologic maps of the southern De Long Mountains quadrangle (fig. 1). Because the geology in the three map areas is similar, a composite map explanation has been designed to facilitate their combined use and give a better perspective of the regional geology. There are some rock units and allochthons which do not occur on all three maps. For this reason, the explanation contains more rock units than occur on any one map. Rock units which appear on the accompanying map are indicated by an asterisk beside the map symbol in the explanation.

Alaska↗

Reconnaissance geologic map of the De Long Mountains A1, B1, and part of C1 quadrangles, Alaska

This map is one of a series of three reconnaissance geologic maps of the southern De Long Mountains quadrangle (fig. 1). Because the geology in the three map areas is similar, a composite map explanation has been designed to facilitate their combined use and give a better perspective of the regional geology. There are some rock units and allochthons which do not occur on all three maps. For this reason, the explanation contains more rock units than occur on any one map. Rock units which appear on the accompanying map are indicated by an asterisk beside the map symbol in the explanation.

Alaska↗

Database for the Geologic Map of the Summit Region of Kilauea Volcano, Hawaii

INTRODUCTION The area covered by this map includes parts of four U.S. Geological Survey (USGS) 7.5' topographic quadrangles (Kilauea Crater, Volcano, Ka`u Desert, and Makaopuhi). It encompasses the summit, upper rift zones, and Koa`e Fault System of Kilauea Volcano and a part of the adjacent, southeast flank of Mauna Loa Volcano. The map is dominated by products of eruptions from Kilauea Volcano, the southernmost of the five volcanoes on the Island of Hawai`i and one of the world's most active volcanoes. At its summit (1,243 m) is Kilauea Crater, a 3 km-by-5 km collapse caldera that formed, possibly over several centuries, between about 200 and 500 years ago. Radiating away from the summit caldera are two linear zones of intrusion and eruption, the east and the southwest rift zones. Repeated subaerial eruptions from the summit and rift zones have built a gently sloping, elongate shield volcano covering approximately 1,500 km2. Much of the volcano lies under water: the east rift zone extends 110 km from the summit to a depth of more than 5,000 m below sea level; whereas, the southwest rift zone has a more limited submarine continuation. South of the summit caldera, mostly north-facing normal faults and open fractures of the Koa`e Fault System extend between the two rift zones. The Koa`e Fault System is interpreted as a tear-away structure that accommodates southward movement of Kilauea's flank in response to distension of the volcano perpendicular to the rift zones. This digital release contains all the information used to produce the geologic map published as USGS Geologic Investigations Series I-2759 (Neal and Lockwood, 2003). The main component of this digital release is a geologic map database prepared using ArcInfo GIS. This release also contains printable files for the geologic map and accompanying descriptive pamphlet from I-2759.

Data Series↗

Implementation plan of the National Cooperative Geologic Mapping Program strategy—Northeast region of the United States: New York and New England

Complexly deformed igneous, metamorphic, and sedimentary rocks form the bedrock of the Northeast region of the United States. Variably thick unconsolidated sediments deposited by glacial, fluvial, and eolian systems locally cover the bedrock. New geologic mapping focuses on areas lacking modern, detailed studies or syntheses, and contributes to existing framework research. This report addresses plans for the continued development of regionally and nationally consistent geologic maps and map databases, efforts to answer outstanding geologic questions, and societal concerns associated with related geologic topics, such as hazards, geologic and hydrologic resources, and environmental issues.

Connecticut, Massachusetts, Maine, New Hampshire, ↗

3-D mapping of the conterminous U.S. within the USGS National Cooperative Geologic Mapping Program: Progress and future prospects

The U.S. Geological Survey (USGS) National Cooperative Mapping Program (NCGMP) is bringing together subsurface and three-dimensional information at multiple scales for the conterminous United States from data produced throughout the USGS and by federal and state partners. Components of this work include data inventory and catalog development, data integration and database development, and construction of subregional and basin-scale three-dimensional (3-D) geologic models. At small scales, the NCGMP is compiling subsurface data to create a limited number of subsurface layers that map the majority of the lower 48 States. At larger scales, 3-D models of stratigraphic units are intended to be the subsurface analog and extension of the surface geologic maps made within the Program. The Mapping Program is developing methods of storing, visualizing, and distributing 3-D models and subsurface data from multiple sources in easily shareable, queryable, non-proprietary format(s). We report on progress in 3-D mapping of the conterminous U.S. and on future prospects.

conterminous United States↗

Database compilation for the geologic map of the San Francisco volcanic field, north-central Arizona

The main component of this publication is a geologic map database prepared using geographic information system (GIS) applications. The geodatabase of geologic points, lines, and polygons was produced as a compilation from five adjoining map sections originally published as printed maps in 1987 (see references in metadata). Four of the sections (U.S. Geological Survey Miscellaneous Field Studies Maps MF–1957, MF–1958, MF–1959, MF–1960) were created by scanning and geo-referencing stable base map material consisting of mylar positives. The final section (MF–1956) was compiled by hand tracing an enlargement of the available printed paper base map onto mylar using a #00 rapidograph pen, the mylar positive was then digitally scanned and geo-referenced. This method was chosen because the original basemap materials (mylar positives) for the MF–1956 section were unavailable at the time of this publication. Due to the condition of the available MF–1956 map section used as the base (which had previously been folded) the accuracy within the boundary of the MF–1956 section is presumed to be degraded in certain areas. The locations of the degraded areas and the degree of degradation within these areas is unclear. Final compilation of the database was completed using the ArcScan toolset, and the Editor toolset in ESRI ArcMap 10.1. Polygon topology was created from the lines and labels were added to the resultant geological polygons, lines, and points. Joseph A. Bard and David W. Ramsey updated and corrected the geodatabase, created the metadata and web presence, and provided the GIS-expertise to bring the geodatabase and metadata to completion. Included are links to files to view or print the original map sheets and the accompanying pamphlets. The orignial geologic maps were prepared under the Geothermal Research Program of the U.S. Geological Survey as a basis for interpreting the history of magmatic activity in the volcanic field. The San Francisco field, which is largely Pleistocene in age, is in northern Arizona, just north of the broad transition zone between the Colorado Plateau and the Basin and Range province. It is one of several dominantly basaltic volcanic fields of the late Cenozoic age situated near the margin of the Colorado Plateau. The volcanic field contains rocks ranging in composition from basalt to rhyolite—the products of eruption through Precambrian basement rocks and approximately a kilometer of overlying, nearly horizontal, Paleozoic and Mesozoic sedimentary rocks. About 500 km 3 of erupted rocks cover about 5,000 km 2 of predominantly Permian and locally preserved Triassic sedimentary rocks that form the erosionally stripped surface of the Colorado Plateau in Northern Arizona.

Arizona↗

Reconnaissance geologic map and geochemical analyses of stream-sediment and rock samples of the Anchorage A-6 quadrangle, Alaska

A reconnaissance geologic map and analytical data for 70 stream-sediment samples and 34 rock samples for the Anchorage A-6 1:63,360 scale quadrangle are presented in this report, together with a statistical treatment of the geochemical data. The bedrock was mapped and samples collected during the summers of 1969, 1970, and 1971 as part of a continuing U.S. Geological Survey project to map basement rocks in the western Chugach Mountains. Most of the early work on the bedrock geology of the Anchorage A-6 quadrangle was done by Capps (1916 and 1940), who studied the geology of the Turnagain-Knik region, and by Park (1933), who studied the Girdwood gold mining district, most of which is in the Anchorage A-6 quadrangle. Recent studies of bedrock in the quadrangle and nearby areas are described in papers by Clark and Bartsch (1971a, b) and Clark (in press, a, b). Grateful acknowledgement is given to several persons who made valuable contributions to this report. They include Henry R. Schmoll and Ernest Dobrovolny who mapped the contacts between bedrock and surficial deposits shown in figure 1, David L. Jones who did the paleontological studies, and Susan R. Bartsch and Pamela S. Morse who participated in the geologic mapping and geochemical sampling.

Alaska↗

Quaternary geologic map of the Dallas 4° x 6° quadrangle, United States

The Quaternary Geologic Map of the Dallas 4° x 6° Quadrangle was mapped as part of the Quaternary Geologic Atlas of the United States. The atlas was begun as an effort to depict the areal distribution of surficial geologic deposits and other materials that accumulated or formed during the past 2+ million years, the period that includes all activities of the human species. These materials are at the surface of the Earth. They make up the ground on which we walk, the dirt in which we dig foundations, and the soil in which we grow crops. Most of our human activity is related in one way or another to these surface materials that are referred to collectively by many geologists as regolith, the mantle of fragmental and generally unconsolidated material that overlies the bedrock foundation of the continent. The maps were compiled at 1:1,000,000 scale.

Texas↗

Geologic map of the central far side of the Moon

This map is one of a series of geologic maps t hat will cover the entire Moon at a scale of 1:5,000,000. The geology of the central far side is compiled largely from NASA Lunar Orbiter and Apollo photographs and Soviet Zond photographs; the discussion and interpretation of geologic units incorporate the geochemical and geophysical data obtained from orbiting s p acecraft. Geologic units are based on the stratigraphic framework established by Shoemaker and Hackman (1962) as subsequently revised (summarized by McCauly , 19 67 ; Wilhelms , 1970; Mutch , 1972; Stuart-Alexander and Wilhelms , 1975). Description of map units is brief because they largely follow units described on the nearside 1:5,000,000 map of Wilhelms and McCauley (1971). The reader unfamiliar with lunar maps, mapping principles, and terminology is referred to that map. Only new units and features or units whose origins are still much in doubt are discussed here.

IMAP↗

Quaternary Geologic Map of the Platte River 4 Degrees x 6 Degrees Quadrangle, United States

The Quaternary Geologic Map of the Platte River 4 degree x 6 degree Quadrangle was mapped as part of the Quaternary Geologic Atlas of the United States. The atlas was begun as an effort to depict the areal distribution of surficial geologic deposits and other materials that accumulated or formed during the past 2+ million years, the period that includes all activities of the human species. These materials are at the surface of the earth. They make up the 'ground' on which we walk, the 'dirt' in which we dig foundations, and the 'soil' in which we grow crops. Most of our human activity is related in one way or another to these surface materials that are referred to collectively by many geologists as regolith, the mantle of fragmental and generally unconsolidated material that overlies the bedrock foundation of the continent. The maps were compiled at 1:1,000,000 scale. This map is part of the Quaternary Geologic Atlas of the United States (I-1420). It was first published as a printed edition in 1994. The geologic data have now been captured digitally and are presented here along with images of the printed map sheet and component parts as PDF files.

IMAP↗