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At least 1,261 records · Page 70Linked to original sources
USGS1979

Geologic map of the Arcadia Quadrangle of Mars

The Arcadia quadrangle of Mars contains three distinct geological provinces: (1) the 1000-km-diameter shield field volcano of Alba Patera, which occupies the southwestern quadrant ; (2) the complex T empe province, which comprises a number of younger volcanic and sedimentary blanket deposits over an ancient, highly cratered crust forming a plateau in the southwestern quadrant ; and (3) a plains province, consisting of northern wind-swept , c ratered plains and some younger subpolar deposits in the northeast corner of the quadrangle, plus less cratered plains surrounding much of the T empe and Alba regions. The plateau, informally named the Tempe Plateau and part of the proposed forma l term Tempe Terra, is separated from the main regions of cratered martian highlands to the south by Kasei Vallis , appearing at the extreme southeast corner of the map, which slopes northeastward onto Chryse Planitia.

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USGS1992

Map showing bottom topography of the Pacific Continental Margin, Cape Mendocino to Point Conception

All contours, geographic outlines, and political boundaries shown on this map of the bottom topography, or bathymetry, of the Pacific continental margin between 34? and 41? N. latitudes were plotted from digital data bases in the library of the U.S. Geological Survey (USGS)-National Oceanic and Atmospheric Administration (NOAA) Joint Office for Mapping and Research (JOMAR). These digital data were obtained and compiled from many sources; consequently, data quality varies within particular data bases as well as from one data base to another. Bathymetric contours were digitized from a map compiled by Chase and others (1981) and from the unpublished large scale versions of that map (T.E. Chase, unpub. maps, 1981). Data for the area seaward of the continental slope (~2000 m depth) were obtained primarily from the U.S. Coast and Geodetic Survey (C&GS) 1955 Pacific Exploratory Survey, a systematic and detailed (~8 -nmi trackline spacing) survey between Mexico and Canada. The USGS provided data from cruises S3-78-NC, S15-79-NC, L2-77-NC, Ll0-76-NC, and Bartlett 72. Data were also obtained from Scripps Institution of Oceanography cruises Merazine, Blue Flash, Kayak B, Scan I, and Seven Tow (Chase and Menard, 1971; Chase and others, 1975; Wilde and others, 1976; Wilde and others, 1978). The 200-m contour was derived from the National Ocean Survey charts 1306N-20 (1975), 1307N-l1B (1974a), 1307N-18B (1974b), and C&GS chart 1308N-12 (1969). Sea-floor depths were corrected for sound velocity in sea water using Matthew's (1939) tables. Onshore topographic contours were generated by computer from a modified version of 3-arc-second elevation data provided by the Defense Mapping Agency. The United States digital shoreline was obtained from the NOAA, NOS, Nautical Charting Division, National Atlas files. The coastline of Canada was digitized from Canadian Hydrographic Service bathymetric maps. The primary source of names of the sea floor features was the "Gazetteer of Undersea Features" (Defense Mapping Agency, 1990). Acknowledgments Christopher Hines assisted in the construction and verification of the digital data bases. Reviews and suggestions by Edward C. Escowitz and Florence Wong and advice provided by Will Stettner regarding the cartographic design substantially improved the quality of this map. References Cited Chase, T.E., and Menard, H.W., 1971, Bathymetric atlas of the northeastern Pacific Ocean: U.S. Naval Oceanographic Office Publication 1303, scale 1:2,000,000 at 33° latitude, 48 p. Chase, T.E., Wilde, Pat, and Normark, W.R., 1975, Oceanographic data of the Monterey Deep Sea Fan: San Diego, University of California, Institute of Marine Resources Publication TR 58, scale 1:898,524 at 35° latitude. Chase, T.E., Wilde, Pat, Normark, W.R., Miller, C.P., Seekins, B.A., and Young, J.D., 1981, Offshore topography of the Western United States between 32° and 49° North latitudes: U.S. Geological Survey Open-File Report 81-443, scale 1:864,518 at 38° latitude, 2 sheets. Coast and Geodetic Survey, 1969, Point St. George to Point Delgada: Coast and Geodetic Survey Bathymetric Map 1308N-12, scale 1:250,000. Defense Mapping Agency, 1990, Gazetteer of undersea features (4th ed.): Washington, D.C., Defense Mapping Agency. Matthews, D.J., 1939, Tables of the velocity of sound in pure water and sea water (2d ed.): London, Admiralty, Hydrographic Department, H.D. 282, 52 p. National Ocean Survey, 1974a, Vicinity Pt. Sur to Pt. Reyes: National Ocean Survey Bathymetric Map 1307N-11B, scale 1:250,000. National Ocean Survey, 1974b, Pt. Reyes to Tolo Bank: National Ocean Survey Bathymetric Map 1307N-18B, scale 1:250,000. National Ocean Survey, 1975, Cape San Martin to Point Conception: National Ocean Survey Bathymetric Map 1306N-20, scale 1:250,000. Wilde, Pat, Normark, W.R., and Chase, T.E., 1976, Oceanographic data off central California 37° to 40° North including the Delgada Deep Sea Fan: Berkeley, University of California, Lawrence Berkeley Laboratory Publication 92, scale 1 :864,581 at 38° latitude. Wilde, Pat, Chase, T.E., Holmes, M.L., Normark, W.R., Thomas, J.A., McCulloch, D.S., and Kulm, L.D., 1978, Oceanographic data off northern California-southern Oregon 40° to 43° North including the Gorda Deep Sea Fan: Berkeley, University of California, Lawrence Berkeley Laboratory Publication 251, scale 1:815,482 at 42° latitude.

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USGS1992

Map showing bottom topography of the Pacific Continental Margin, Strait of Juan de Fuca to Cape Mendocino

All contours, geographic outlines, and political boundaries shown on this map of the bottom topography, or bathymetry, of the Pacific continental margin between 34° and 41° N. latitudes were plotted from digital data bases in the library of the U.S. Geological Survey (USGS)-National Oceanic and Atmospheric Administration (NOAA) Joint Office for Mapping and Research (JOMAR). These digital data were obtained and compiled from many sources; consequently, data quality varies within particular data bases as well as from one data base to another. Bathymetric contours were digitized from a map compiled by Chase and others (1981) and from the unpublished large scale versions of that map (T.E. Chase, unpub. maps, 1981). Data for the area seaward of the continental slope (~2000 m depth) were obtained primarily from the U.S. Coast and Geodetic Survey (C&GS) 1955 Pacific Exploratory Survey, a systematic and detailed (~8 -nmi trackline spacing) survey between Mexico and Canada. The USGS provided data from cruises S3-78-NC, S15-79-NC, L2-77-NC, Ll0-76-NC, and Bartlett 72. Data were also obtained from Scripps Institution of Oceanography cruises Merazine, Blue Flash, Kayak B, Scan I, and Seven Tow (Chase and Menard, 1971; Chase and others, 1975; Wilde and others, 1976; Wilde and others, 1978). The 200-m contour was derived from the National Ocean Survey charts 1306N-20 (1975), 1307N-l1B (1974a), 1307N-18B (1974b), and C&GS chart 1308N-12 (1969). Sea-floor depths were corrected for sound velocity in sea water using Matthew's (1939) tables. Onshore topographic contours were generated by computer from a modified version of 3-arc-second elevation data provided by the Defense Mapping Agency. The United States digital shoreline was obtained from the NOAA, NOS, Nautical Charting Division, National Atlas files. The coastline of Canada was digitized from Canadian Hydrographic Service bathymetric maps. The primary source of names of the sea floor features was the "Gazetteer of Undersea Features" (Defense Mapping Agency, 1990). Acknowledgments Christopher Hines assisted in the construction and verification of the digital data bases. Reviews and suggestions by Edward C. Escowitz and Florence Wong and advice provided by Will Stettner regarding the cartographic design substantially improved the quality of this map. References Cited Chase, T.E., and Menard, H.W., 1971, Bathymetric atlas of the northeastern Pacific Ocean: U.S. Naval Oceanographic Office Publication 1303, scale 1:2,000,000 at 33° latitude, 48 p. Chase, T.E., Wilde, Pat, and Normark, W.R., 1975, Oceanographic data of the Monterey Deep Sea Fan: San Diego, University of California, Institute of Marine Resources Publication TR 58, scale 1:898,524 at 35° latitude. Chase, T.E., Wilde, Pat, Normark, W.R., Miller, C.P., Seekins, B.A., and Young, J.D., 1981, Offshore topography of the Western United States between 32° and 49° North latitudes: U.S. Geological Survey Open-File Report 81-443, scale 1:864,518 at 38° latitude, 2 sheets Coast and Geodetic Survey, 1969, Point St. George to Point Delgada: Coast and Geodetic Survey Bathymetric Map 1308N-12, scale 1:250,000. Defense Mapping Agency, 1990, Gazetteer of undersea features (4th ed.): Washington, D.C., Defense Mapping Agency. Matthews, D.J., 1939, Tables of the velocity of sound in pure water and sea water (2d ed.): London, Admiralty, Hydrographic Department, H.D. 282, 52 p. National Ocean Survey, 1974a, Vicinity Pt. Sur to Pt. Reyes: National Ocean Survey Bathymetric Map 1307N-11B, scale 1:250,000. National Ocean Survey, 1974b, Pt. Reyes to Tolo Bank: National Ocean Survey Bathymetric Map 1307N-18B, scale 1:250,000. National Ocean Survey, 1975, Cape San Martin to Point Conception: National Ocean Survey Bathymetric Map 1306N-20, scale 1:250,000. Wilde, Pat, Normark, W.R., and Chase, T.E., 1976, Oceanographic data off central California 37° to 40° North including the Delgada Deep Sea Fan: Berkeley, University of California, Lawrence Berkeley Laboratory Publication 92, scale 1 :864,581 at 38° latitude. Wilde, Pat, Chase, T.E., Holmes, M.L., Normark, W.R., Thomas, J.A., McCulloch, D.S., and Kulm, L.D., 1978, Oceanographic data off northern California-southern Oregon 40° to 43° North including the Gorda Deep Sea Fan: Berkeley, University of California, Lawrence Berkeley Laboratory Publication 251, scale 1:815,482 at 42° latitude.

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USGS1994

Geologic map of the MTM -85080 quadrangle (revised), Planum Australe region of Mars

Published geologic maps of south polar region of Mars have been based on either Mariner 9 (Condit Soderblom, 1978; Scott and Carr, 1978) or Viking Orbiter (Tanaka and Scott, 1987) images. The mapped extent of the southern layered deposits differs in many places on these maps and on our maps. These differences reflect the difficulty in accurately determining the location of the contact between the layered deposits and subjacent units. The polar layered deposit gradually thin toward their margin in many places, and the smooth surface features that characterize the layered deposits are also found on other sedimentary blankets in the south polar region (Murray and others, 1972; Sharp, 1973). Previous workers have also reached different conclusions regarding the origin of the lower member of the Dorsa Argentea Formation, which was named by Tanaka and Scott (1987) and interpreted by them as volcanic in origin (based on observation of flow fronts in areas far outside this quadrangle). The lower member, previously called pitted material, and other sedimentary, and other sedimentary units were recognized in Mariner 9 images and described by Murray and others (1972), Sharp (1973), and Cutts (1973b). Sharp (1973) argued for exhumation of pits by wind, perhaps aided by sublimation of volatiles. He concluded that the massive pitted sediments of the lower member unconformably overlie older massive units. We have mapped one of these older units ridged and knobby material. Condit and Soderblom (1978) found some layered deposits within pits, which indicates that erosion of the pits was completed before accumulation of the layered deposits commenced. Howard’s (1981) suggestion that the pits may be formed by basal melting of ground ice is consistent with either a volcanic or sedimentary origin for the lower (pitted) member. Plaut and others (1988) mapped the extent of the pitted material and found that it overlies volcanic plains wherever the contact is visible. They concluded that the pitted material is no more than 1 km thick and is about 3.3 billion years old (Late Hesperian).

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USGS1999

Geologic map of the Barrymore Quadrangle (V-59), Venus

The Barrymore quadrangle (V–59) is a predominantly ridged plains region south of Imdr Regio, incorporating portions of Helen, Nuptadi, and Nsomeka Planitiae. The map area extends from lat 50°–75° S. and long 180°–240°, with nearly 70% coverage by cycle 1 synthetic aperture radar (SAR) images (left-look, incidence angles 16°–23°) and complete coverage by cycle 2 images (right-look, incidence angles 20°–25°) (fig. 1). The majority of the map area is covered by regional plains material that may either be smooth or deformed by wrinkle ridges or ridge belts of variable spacing. The difference in elevation between highest and lowest points in the map area is about 2.3 km. A north-south-oriented, 1,375-km linear ridge belt named “Saule Dorsa” is in the center of the region. The southern tip of this belt is intersected by a stratigraphically complicated, east-west-trending intermittent series of disrupted material, arcuate depressions and rises, regional plains, and volcanic centers. This region (hereafter referred to as the “east-west disrupted zone”) lies within a belt between 63°–67° S. extending from Kadlu Dorsa to Moombi Corona. A high concentration of canali-type channels (long sinuous lava channels that may contain subsidiary channels that branch off from the main channel [Baker and others, 1992; Komatsu and others, 1992]) occurs in Nsomeka Planitia. This includes Xulab Vallis and Citlalpul Valles, which form the eastern extent of a 3,000-km-long canali system (Komatsu and others, 1993). Three instances of canali bifurcation from north-south to east-west orientations occur in this region (fig. 2). Several large impact craters with fluidized ejecta blanket (FEB) outflows occur in the map area, along with some impact crater extended deposits (parabolas). The latter are mapped as surficial material using stipple patterns over the plains materials. These surficial deposits show variations in radar backscatter properties between cycle 1 and cycle 2 images related to orientation of aeolian dune or ripple faces (for example, Weitz and others, 1994; table 1). This region provides an interesting geologic setting for interpreting the history of regional and local plains formation and evolution, mainly due to development and subsequent deformation of the areally extensive plains units and accompanying canali (Komatsu and Baker, 1994).

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USGS2001

Geologic Map of the MTM-85000 Quadrangle, Planum Australe Region of Mars

Introduction The polar deposits on Mars probably record martian climate history over the last 107 to 109 years (for example, Thomas and others, 1992). The area shown on this map includes layered polar deposits and residual polar ice, as well as some exposures of older terrain. Howard and others (1982) noted that an area (at lat 84.8 S., long 356 W.) near a 23-km diameter impact crater (Plaut and others, 1988) appears to have undergone recent deposition, as evidenced by the partial burial of secondary craters. Herkenhoff and Murray (1990a) mapped this area as a mixture of frost and defrosted ground and suggested that the presence of frost throughout the year stabilizes dust deposited in this area. This quadrangle was mapped using high-resolution Mariner 9 (table 1) and Viking Orbiter images in order to study the relations among erosional, cratering, and depositional processes on the polar layered deposits and to search for further evidence of recent deposition. Published geologic maps of the south polar region of Mars are based on images acquired by Mariner 9 (Condit and Soderblom, 1978; Scott and Carr, 1978) and the Viking Orbiters (Tanaka and Scott, 1987). The extent of the layered deposits mapped previously from Mariner 9 data is different from that mapped using Viking Orbiter images, and the present map agrees with the map by Tanaka and Scott (1987): the layered deposits extend to the northern boundary of the map area. However, the oldest unit in this area is mapped as undivided material (unit HNu) rather than the hilly unit in the plateau sequence (unit Nplh; Tanaka and Scott, 1987). The residual polar ice cap, areas of partial frost cover, the layered deposits, and two nonvolatile surface units-the dust mantle and the dark material-were mapped by Herkenhoff and Murray (1990a) at 1:2,000,000 scale using a color mosaic of Viking Orbiter images. This mosaic was used to confirm the identification of the non-volatile Amazonian units for this map and to test hypotheses for their origin and evolution. The colors and albedos of these units, as measured in places both within and outside of this map area, are presented in table 2 and figure 1. The red/violet ratio image was particularly useful in distinguishing the various low-albedo materials, as brightness variations due to topography are essentially removed in such ratio images and color variations are easily seen. Because the resolution of the color mosaics is not sufficient to map these units in detail at 1:500,000 scale, contacts between them were recognized and mapped using higher resolution black and white Viking and Mariner 9 images. The largest impact crater in the layered deposits, 23 km in diameter at lat 84.5 S., long 359 W., now named 'McMurdo,' was recognized by Plaut and others (1988). The northern rim of this crater is missing, perhaps due to erosion of the layered deposits in which it was formed (fig. 2). Secondary craters from this impact are not observed north of the crater but are abundant to the south. Although the crater statistics are poor (only 16 likely impact craters found in Viking Orbiter images of the south polar layered deposits), these observations generally support the conclusions that the south polar layered deposits are Late Amazonian in age and that some areas have been exposed for about 120 million years (Plaut and others, 1988; Herkenhoff and Murray, 1992, 1994; Herkenhoff, 1998). However, the recent cratering flux on Mars is poorly constrained, so inferred ages of surface units are uncertain. The Viking Orbiter 2 images used to construct the base were taken during the southern summer of 1977, with resolutions no better than 130 m/pixel. A digital mosaic of Mariner 9 images also was constructed to aid in mapping. The Mariner 9 images were taken during the southern summer of 1971 and 1972 and have resolutions as high as 85 m/pixel (table 1). However, the usefulness of the Mariner 9 mosaic image is limited by incomplete coverag

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USGS2001

Geologic Map of the Hellas Region of Mars

INTRODUCTION This geologic map of the Hellas region focuses on the stratigraphic, structural, and erosional histories associated with the largest well-preserved impact basin on Mars. Along with the uplifted rim and huge, partly infilled inner basin (Hellas Planitia) of the Hellas basin impact structure, the map region includes areas of ancient highland terrain, broad volcanic edifices and deposits, and extensive channels. Geologic activity recorded in the region spans all major epochs of martian chronology, from the early formation of the impact basin to ongoing resurfacing caused by eolian activity. The Hellas region, whose name refers to the classical term for Greece, has been known from telescopic observations as a prominent bright feature on the surface of Mars for more than a century (see Blunck, 1982). More recently, spacecraft imaging has greatly improved our visual perception of Mars and made possible its geologic interpretation. Here, our mapping at 1:5,000,000 scale is based on images obtained by the Viking Orbiters, which produced higher quality images than their predecessor, Mariner 9. Previous geologic maps of the region include those of the 1:5,000,000-scale global series based on Mariner 9 images (Potter, 1976; Peterson, 1977; King, 1978); the 1:15,000,000-scale global series based on Viking images (Greeley and Guest, 1987; Tanaka and Scott, 1987); and detailed 1:500,000-scale maps of Tyrrhena Patera (Gregg and others, 1998), Dao, Harmakhis, and Reull Valles (Price, 1998; Mest and Crown, in press), Hadriaca Patera (D.A. Crown and R. Greeley, map in preparation), and western Hellas Planitia (J.M. Moore and D.E. Wilhelms, map in preparation). We incorporated some of the previous work, but our map differs markedly in the identification and organization of map units. For example, we divide the Hellas assemblage of Greeley and Guest (1987) into the Hellas Planitia and Hellas rim assemblages and change the way units within these groupings are identified and mapped (table 1). The new classification scheme includes broad, geographically related categories and local, geologically and geomorphically related subgroups. Because of our mapping at larger scale, many of our map units were incorporated within larger units of the global-scale mapping (see table 1). Available Viking images of the Hellas region vary greatly in several aspects, which has complicated the task of producing a consistent photogeologic map. Best available image resolution ranges from about 30 to 300 m/pixel from place to place. Many images contain haze caused by dust clouds, and contrast and shading vary among images because of dramatic seasonal changes in surface albedo, opposing sun azimuths, and solar inclination. Enhancement of selected images on a computer-display system has greatly improved our ability to observe key geologic relations in several areas. Determination of the geologic history of the region includes reconstruction of the origin and sequence of formation, deformation, and modification of geologic units constituting (1) the impact-basin rim and surrounding highlands, (2) volcanic and channel assemblages on the northeast and south sides of the basin, (3) interior basin deposits, and (4) slope and surficial materials throughout the map area. Various surface modifications are attributed to volcanic, fluvial, eolian, mass-wasting, and possibly glacial and periglacial processes. Structures include basin faults (mostly inferred), wrinkle ridges occurring mainly in volcanic terrains and interior plains, volcanic collapse craters, and impact craters. Our interpretations in some cases rely on previous work, but in many significant cases we have offered new interpretations that we believe are more consistent with the observations documented by our mapping. Our primary intent for this mapping has been to elucidate the history of emplacement and modification of Hellas Planitia materials, which form the basis for analysis of their r

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USGS2001

Geologic map of Colorado National Monument and adjacent areas, Mesa County, Colorado

New 1:24,000-scale geologic mapping in the Colorado National Monument Quadrangle and adjacent areas, in support of the USGS Western Colorado I-70 Corridor Cooperative Geologic Mapping Project, provides new interpretations of and data for the stratigraphy, structure, geologic hazards in the area from the Colorado River in Grand Valley onto the Uncompahgre Plateau. The plateau drops abruptly along northwest-trending structures toward the northeast 800 m to the Redlands area and the Colorado River in Grand Valley. In addition to common alluvial and colluvial deposits, surficial deposits include Holocene and late Pleistocene charcoal-bearing valley-fill deposits, late to middle Pleistocene river-gravel terrace deposits, Holocene to middle Pleistocene younger, intermediate, and old fan-alluvium deposits, late to middle Pleistocene local gravel deposits, Holocene to late Pleistocene rock-fall deposits, Holocene to middle Pleistocene young and old landslide deposits, Holocene to late Pleistocene sheetwash deposits and eolian deposits, and Holocene Cienga-type deposits. Only the lowest part of the Upper Cretaceous Mancos Shale is exposed in the map area near the Colorado River. The Upper and Lower? Cretaceous Dakota Formation and the Lower Cretaceous Burro Canyon Formation form resistant dipslopes in the Grand Valley and a prominent ridge on the plateau. Less resistant strata of the Upper Jurassic Morrison Formation consisting of the Brushy Basin, Salt Wash, and Tidwell Members form slopes on the plateau and low areas below the mountain front of the plateau. The Middle Jurassic Wanakah Formation nomenclature replaces the previously used Summerville Formation. Because an upper part of the Middle Jurassic Entrada Formation is not obviously correlated with strata found elsewhere, it is therefore not formally named; however, the lower rounded cliff former Slickrock Member is clearly present. The Lower Jurassic silica-cemented Kayenta Formation forms the cap rock for the Lower Jurassic carbonate-cemented Wingate Sandstone, which forms the impressive cliffs of the monument. The Upper Triassic Chinle Formation was deposited on the eroded and weathered Middle Proterozoic meta-igneous gneiss, pegmatite dikes, and migmatitic gneiss. Structurally the area is deceptively challenging. Nearly flat-lying strata on the plateau are folded by northwest-trending fault-propagation folds into at least two S-shaped folds along the mountain front of the plateau. Strata under Grand Valley dip at about 6 degrees to the northeast. In the absence of local evidence, the uplifted plateau is attributed to Laramide deformation by dated analogous structures elsewhere in the Colorado Plateau. The major exposed fault records high-angle reverse relationships in the basement rocks but dissipates strain as a triangular zone of distributed microfractures and cataclastic flow into overlying Mesozoic strata that absorb the fault strain, leaving only folds. Evidence for younger, probably late Pliocene or early Pleistocene, uplift does exist at the antecedent Unaweep Canyon south and east of the map area. To what degree this younger deformation affected the map area is unknown. Several geologic hazards affect the area. Middle and late Pleistocene landslides involving the smectite-bearing Brushy Basin Member of the Morrison Formation are extensive on the plateau and common in the Redlands below the plateau. Expansive clay in the Brushy Basin and other strata create foundation stability problems for roads and homes. Flash floods create a serious hazard to people on foot in narrow canyons in the monument and to homes close to water courses downstream from narrow restrictions close to the monument boundary.

Colorado↗
USGS1967

(LAC-38) Geologic map of the Seleucus quadrangle of the moon

The Seleucus quadrangle lies in the northwestern part of the Oceanus Procellarum , a large mare of irregular shape in the western part of the earthside hemisphere of the Moon. Material of the mare occupies most of the quadrangle. Craters ranging from 1 to 44 km in diameter are scattered over the smooth mare surface; in addition, a few isolated hills and ridges rise above the mare. In the east-central part of the quadrangle, the Aristarchus plateau (informal name ) slopes gently westward and merges with the surrounding surface of Oceanus Procellarum . The plat eau is also known for its reddish color and light absorption properties (Wood, 1912), and areas where occasional reddish glows have been seen (Greenacre, 1965).

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USGS1972

Map showing springs in the Salina quadrangle, Utah

A spring is “a place where, without the agency of man, water flows from a rock or soil upon the land or into a body of surface water” (Meinzer, 1923, p. 48). About 450 springs are located on this map. Locations and names are from the U.S. Forest Service maps (1963, 1964) and from topographic maps of the U.S. Geological Survey, both published and in preparation. There is considerable variation in geological occurrence of the springs and in quantity and chemical quality of the water that issues from them. Springs in the Salina quadrangle are more abundant where annual precipitation is 16 inches or more, although there are many springs in arid parts of the quadrangle as well. In the Salina quadrangle, springs are used most commonly for watering livestock. They are used also for irrigation and for domestic and municipal water supply. Several communities in Rabbit Valley, Grass Valley, and Sevier Valley depend on springs for all or part of their water supply. Quantity and quality of water are shown for those few springs for which data are available (Mundorff, 1971). Caution must be used in drinking from springs, especially in arid areas; the water commonly tastes bad and may cause illness.

Utah↗
USGS1976

Geologic map of the Oxia Palus Quadrangle of Mars

The Oxia Palus quadrangle contains three distinct geologic provinces: (1) an elevated cratered plateau that occupies three-fourths of the quadrangle and is similar to much of the southern hemisphere of Mars; (2) the low, relatively featureless Chryse Planitia in the northwest corner; and (3) a complex province of chaotic terrain and immense channels or valleys that divides the plateau and terminates in Chryse Planitia. Generally, the oldest geologic units occur in the plateau province and the youngest in Chryse Planitia. Discovery by Mariner 9 of the channels, the four largest of which are given names meaning “Mars” in Akkadian, Sumerian, Angelo-Saxon, and Greek (west to east), renews the possibility of water and therefore life on Mars. This possibility may be tested in July 196 by a landing of the unmanned Viking spacecraft in Chryse Planitia at the mouths of the channels (lat 19 1/2˚ N., long 34˚).

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USGS1978

Geologic map of the Phoenicis Lacus Quadrangle of Mars

The Phoenicis Lacus quadrangle (named Lake of the Pheonix by Schiaparelli, 1 877) includes some of the largest geologic features recognized on the terrestrial planets. Arsia and Pavonis Montes, (“South Spot” and “Middle Spot” of Mariner 9) rise 18 and 17 km, respectively, above the surrounding plateau to an elevation of about 27 km above the 6.1 millibar base level. These mountains and the two large volcanoes Ascraeus and Olympus Montes, located outside the quadrangle to the north, are also about 27 km in height , about three times as high as any volcano on Earth. The summit caldera of Arsia Mons. m ore than 100 km in diameter, is the largest known. Syria and Sinai Plana are part of t he highest plat eau on Mars, the Tharsis plateau; their relative elevation, 10 km , is twice that of the Tibetan Plateau, the highest plateau on Earth . Noctis Labyrinthus , the great system of fault valleys at the we st end of Valles Marineris which is located o u tside the quadrangle to the east, displays a more clearly developed system of faults tha n the largest continental fault system on Earth, the East African rift valleys. The land slopes down to the northwest into Amazonis Planitia (fig. 1); the difference in elevation between the volcanic peaks and Amazonis low plains is greater than the relief form the top of the Andes to the bottom of the Peruvian trench. Th is great slope on Mars is similar to the continental shelf and slope that marks the transition bet ween the continents and ocean basin floors of the Ear th.

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USGS1980

Correlation of coal beds, coal zones, and key stratigraphic units in the Pennsylvanian rocks of eastern Kentucky

The Pennsylvanian rocks of the eastern Kentucky coal field unlderlie an area of about 27,000 square kilometers (see index map). Largely because of the size and stratigraphic complexity of the area, Huddle and others (1963, p. 31) divided it into six coal reserve districts (unofficial), utilizing state and county lines as well as geologic features, drainage areas, and cola producing areas. This division is followed herein because, in general, each of these districts has a characteristic stratigraphic nomenclature, particularly as related to coal bed names. The six districts shown on the index mat, are the Princess, Licking River, Big Sandy, Hazard, Southwestern, and Upper Cumberland River; the Upper Cumberland River district has been divided into the Harlan and Middlesboro subdistricts.

Kentucky↗
USGS1980

Maps showing coal resources of the Crumpler quadrangle, Mercer, McDowell, and Wyoming Counties, West Virginia

Coal Geology The Crumpler quadrangle lies in the Appalachian Plateaus province, with the coal bearing Pocahontas and New River Formations of Pennsylvanian age having a gentle dip toward the northwest. Coal bed maps were prepared (figures 1-7) and resources were estimated (table 1) for seven of the many coal beds in the Crumpler quadrangle (Stricker, 1980, lists the names of the various coal beds in the quadrangle) following methods established by U.S. Bureau of Mines and U.S. Geological Survey, 1976. All of these coal beds crop out at the surface in the quadrangle, have a maximum thickness thickness of over-burden of less than 300 meters, and have been mined at the surface, or under-ground, or both. Resource estimates were not calculated for other coal beds in the Pocahontas and New River Formations, either because of insufficient data of because of the beds are too thin. Figure 8 is a generalized stratigraphic column of the coal-bearing sequence in the Crumpler quadrangle showing thickness and relative positions of the various coal beds. The Crumpler quadrangle originally contained about 498 million metric tons of coal. Approximately 326 million metric tons have been mined, or lost in mining, leaving remaining resources of 172 million metric tons. Analyses of the mined coal beds in the Crumpler and adjacent quadrangle show the coal is medium - to low volatile bituminous (most are low volatile bituminous), containing 14-27 percent volatile matter (with an arithmetic mean of 18 percent), 2.1-22.4 percent ash (with an arithmetic mean of 7 percent), and 0.5-1.8 percent total sulfur (with an arithmetic mean of 0.8 percent). Heating values range from 6,380 to 8,610 Kcal/kg on an as-received basis. Trace element and major and minor oxide composition, of both whole coal and laboratory ash, for 59 samples within or near the quadrangle were obtained from USCHEM (Geochemical Data File or National Coal Resources Data System), (Kozey and others, 1980.) Neither elements of environmental concern such as arsenic, lead, mercury, and selenium nor potentially valuable elements such as germanium, uranium and thorium were found in significant amounts in the coal.

West Virginia↗
USGS1981

Geologic map of the Troublesome Roadless Area, McCreary County, Kentucky

The Troublesome Roadless Area is composed of six tracts of land and contains 2,943 acres (fig. 1). The largest tract of the study area, located 13 mi southwest of Stearns, Ky., is accessible from that town via State Route 92 to Hill Top, and . then southwestwatd along country roads. Unimproved Forest Service roads, abandoned logging roads, and primitive trails provide access by foot or horseback into the interior of each tract of the study area. Physiographically, the Troublesome Roadless Area is in the Cumberland Plateau section of the Appalachian Plateaus Province and is near the western edge of the Appalachian coal region. The topography is typical of the Cumberland Plateau section, characterized by irregular, narrow-crested ridges, deep narrow canyons, and a dendritic drainage pattern. Troublesome Creek, a small tributary of the South Fork of the Cumberland River, is the source of the area name (fig. 2). Altitudes range from about 1,600 ft on Laurel Ridge in the largest tract to approximately 800 ft along the South Fork of the Cumberland River. Field investigations by personnel of the U.S. Geological Survey consisted of reconnaissance geologic studies and data collecting, including the measurement of stratigraphic sections and the mapping of poorly exposed coal beds and resistant sandstone units. Additional subsurface information was obtained by studying and interpreting the logs of several coreholes drilled near the study area.

Kentucky↗
USGS1985

Reference section for the Minturn Formation (Middle Pennsylvanian), northern Sangre de Cristo Range, Custer County, Colorado

This reference section of the Middle Pennsylvanian Minturn Formation was measured in the northern Sangre de Cristo Range; the section provides a basis for comparison with the type Minturn and with possibly equivalent strata elsewhere in southern Colorado. The name "Minturn" was first applied to strata of Middle Pennsylvanian age near the town of Minturn in central Colorado (Tweto, 1949, p. 194-228; Tweto and Lovering, 1977, p. 33–53), about 180 km north of the section described, and has been extended to strata of approximately the same age that contain marine limestones in the northern Sangre de Cristo Range (Brill, 1952; Bolyard, 1959; Scott and Taylor, 1974). The Minturn reference section continues upward into the principal reference section of the overlying Pennsylvanian and Permian Sangre de Cristo Formation (Lindsey and Schaefer, 1984), and these two sections together provide a continuous record of upper Paleozoic strata in the northern Sangre de Cristo Range. The reference section was measured by tape and compass in the summer of 1980; observations were recorded on a microcassette tape recorder in the field and transcribed in the office. This method permitted rapid acquisition of data on thickness, mature of contacts, color, grain size, and sedimentary features. These data are shown on the graphic section for each distinct rock unit. Rock units having common attributes or genetic relationships have been grouped together for descriptive and interpretative purposes.

Colorado↗