Surficial Geology of the Middle Gila River Area, Plate 5 Teapot Mountain, North-Central Pinal County, Arizona v. 2.0

Most of southern and western Arizona is covered with unconsolidated basin sediments that are not mapped in detail. Although these sediments have diverse physical characteristics, origins, and ages, they are generally mapped as generic units (e.g., Qal). This lack of detailed mapping is not unique to Arizona; it is estimated that 80% of the United States is still unmapped at intermediate or detailed scales (Molnia, 1992: 191). With recent developments in geologic dating techniques and improved understanding of weathering processes, there is now greater opportunity to distinguish and map unconsolidated sediments into genetic and temporal units. Recently, concerns in environmental geology have provided the impetus for surficial geologic mapping in Arizona (Demsey, 1989; Jackson, 1990; Field and Pearthree, 1991; Huckleberry, 1992a). These maps are of value to the scientific community because they provide insight into paleoenvironments and geomorphic history (Bull, 1991). More importantly, however, surficial geologic maps " ... can be applied to land-use management, assessment, and utilization, conservation of natural resources, groundwater management, and environmental protection. II (National Geological Mapping Act of 1992 (Section 2(b»). A recent example of the applied value of surficial geological mapping is the re-evaluation of flood hazards on alluvial fans (Pearthree, 1991). Surficial geology of the Middle Gila River Area, north-central Pinal County, Arizona, 5 map sheets, scale 1:24,000, with report. This geodatabase is part of a digital republication of a 1993 geologic map originally created by the Arizona Geological Survey with financial support from U.S. Geological Survey COGEOMAP Program. Preparation for republication was conducted by students from the University of Arizona with financial support from the U.S. Geological Survey, National Geological and Geophysical Data Preservation Program (G23AP00215) and included the production of a new GIS geodatabase and a revised map layout. It is based on interpretations that were made from the data available at the time it was created. The AZGS does not guarantee this map or digital data to be free of errors nor assume liability for interpretations made from this map or digital data, or decisions based thereon. The views and conclusions contained in this document are those of the authors and should not be interpreted as necessarily representing the official policies, either expressed or implied, of the U.S. Government.