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At least 127 records · Page 7Linked to original sources
USGS2002

Spatial digital database for the tectonic map of southeast Arizona

A spatial database was created for Drewes' (1980) tectonic map of southeast Arizona: this database supercedes Drewes and others (2001, ver. 1.0). Staff and a contractor at the U.S. Geological Survey in Tucson, Arizona completed an interim digital geologic map database for the east part of the map in 2001, made revisions to the previously released digital data for the west part of the map (Drewes and others, 2001, ver. 1.0), merged data files for the east and west parts, and added additional data not previously captured. Digital base map data files (such as topography, roads, towns, rivers and lakes) are not included: they may be obtained from a variety of commercial and government sources. This digital geospatial database is one of many being created by the U.S. Geological Survey as an ongoing effort to provide geologic information in a geographic information system (GIS) for use in spatial analysis. The resulting digital geologic map database can be queried in many ways to produce a variety of geologic maps and derivative products. Because Drewes' (1980) map sheets include additional text and graphics that were not included in this report, scanned images of his maps (i1109_e.jpg, i1109_w.jpg) are included as a courtesy to the reader. This database should not be used or displayed at any scale larger than 1:125,000 (for example, 1:100,000 or 1:24,000). The digital geologic map plot files (i1109_e.pdf and i1109_w.pdf) that are provided herein are representations of the database (see Appendix A). The map area is located in southeastern Arizona (fig. 1). This report describes the map units (from Drewes, 1980), the methods used to convert the geologic map data into a digital format, the ArcInfo GIS file structures and relationships, and explains how to download the digital files from the U.S. Geological Survey public access World Wide Web site on the Internet. The manuscript and digital data review by Helen Kayser (Information Systems Support, Inc.) is greatly appreciated.

Arizona↗
USGS1979

Geologic map of the Amenthes Quadrangle of Mars

The Amenthes quadrangle includes two main physiographic and geologic subdivisions. In the southern part of the quadrangle, densely cratered plateaus rise about 3 km above sparsely to moderately cratered plains. The low plains that form Elysium Planitia also build the eastern flank of the Isidis basin, which mostly lies with the adjacent Syrtis Major quadrangle to the west: the Elysium region, one of the main volcanic centers of Mars, is located to the east. Some of the geologic and tectonic units in the Amenthes quadrangle are related to this volcanic and uplifted zone. Geologic mapping is based mainly on morphological criteria together with some albedo, superposition, and crater-density data from both high- and low- resolution Mariner 9 images. Interpretations of rock units were made by comparison with well-known geologic features on the Earth and the Moon. To determine the absolute ages of map units, crater-counting methods in connection with an updated version of the crater-frequency curve of Neukem and Wise (1976) (fig. 1) were used. However, the application of this method in the Amenthes region is limited by the low resolution and lack of optimum image quantity.

IMAP↗
USGS1978

Geologic map of the Aeolis Quadrangle of Mars

Two principal physiographic provinces of Mars are represented in the Aeolis quadrangle: (1) Elysium Plan itia in the north is part of a broad planet-encircling belt of relatively young lowland plains, and (2) cratered highlands in the south consist of roughly primitive terrain that extends to polar deposits around the southern ice cap (Condit and Soderblom, 1978: Scott and Carr , 1978). These two terrains are separated by an irregular discont inuous northwest-trending scarp that becomes less conspicuous and more segmented toward the east part of the ma p area. Two large channels transect the highlands; they widen northward downslope and have other features cha racteristic of terrestrial river beds . However, now fans or deltaic forms are visible at their mouths and their floors merge with the plains. One large shield volcano, Apollinaris Patera, projects above the plains adjacent to the highlands in the northeast part of the quadrangle. More than 4 km of relief occur across the region from the high plateau in the south and west, downslope northward to plains.

IMAP↗