The Cave Creek quadrangle is located along the northernmost fringe of the Phoenix metropolitan area, and is bordered by the Paradise Valley to the south and high-standing mesas to the north. Given its location, the Cave Creek area is becoming increasingly urbanized and is undergoing rapid population growth. Thus, the knowledge of the distribution and character of bedrock and surficial deposits is important to make informed decisions concerning management of the land and its resources. Geologic mapping of the Cave Creek quadrangle is related to other previous and ongoing mapping projects of urban fringe areas located to the north and northeast of the Phoenix metropolitan area (figure 1). Access for most parts of the Cave Creek quadrangle is excellent (figure 2). Numerous paved roads (e.g., Scottsdale Road, Cave Creek Road, Carefree Highway) and well-maintained dirt roads make much of the quadrangle highly accessible. Access within the Cave Creek Recreation area is limited to the established trail system, unless permission from the park rangers is obtained. Building construction is active across the area, and several large, gated housing developments restrict the access to previously accessible areas; permission is required to enter several of these developments (e.g., Desert Mountain). Geologic mapping of bedrock in the quadrangle was based on field mapping, whereas surficial mapping was based upon both field observations and interpretation of aerial photographs. A series of black-and-white, 1:48,000-scale aerial photographs (dated 9-17-92) and color, 1:24,000-scale aerial photographs (dated 11-5-79 and 6-11-88) were obtained from the Tonto National Forest office in Phoenix. This study.is contiguous with geologic mapping recently completed in the Wildcat Hill quadrangle to the east (Skotnicki and others, 1997). Geologic map of the Cave Creek Quadrangle, Maricopa County, Arizona. Report, one map sheet, scale1:24,000, and one sheet of cross-sections.

The Biscuit Flat Quadrangle is located in the northwestern Phoenix metropolitan area, between Interstate 17 (I-17) and the Agua Fria River (Figure 1). The quadrangle is bounded by latitudes 33°45'00"N and 33°52'30"N, and longitudes 112°07'30"W and 112°15'00"W. Unlike areas to the south and southeast, the Biscuit Flat area is not (as yet) urbanized. However, knowledge of the distribution and character of bedrock and surficial deposits may be important to make informed decisions concerning future management of the land and its resources. Geologic mapping of the Biscuit Flat Quadrangle is related to other 1 :24,000 scale mapping projects in and around the Phoenix metropolitan area (Figure 1). Geologic mapping was based on both field observations and interpretation of aerial photographs and soil surveys. Mapping of Quaternary surficial deposits was initially done by Huckleberry, whereas final mapping and interpretation of surficial deposits and bedrock areas was completed by Leighty. A limited amount of unpublished Arizona Geological Survey mapping (by Steve Reynolds and Mike Grubensky for the Phoenix North 1:100,000 scale geologic map) augmented the new mapping of this report. Also, the mapping of Tertiary rocks by Jagiello (1987) is locally similar to that of this report. Aerial photographic coverage of the quadrangle is available from various sources (e.g., U.S.G.S., Bureau of Land Management, etc.), and includes black-and-white (1:40,000 scale, dated 9-6-92), false-color high-altitude (dated 5-17-81), and color (1:24,000 scale, dated 10-25-77) photographs. Soil information was compiled from USDA Maricopa County soil surveys (Hartman, 1977; Camp, 1986). This project was funded by the Environmental Protection Agency through the State Indoor Radon Grant Program, the U.S. Geological Survey via the STATEMAP program, and the Arizona Geological Survey. Geologic map of the Biscuit Flat 7.5' Quadrangle, Maricopa County, Arizona - report and one map sheet, scale 1:24,000.

The Union Hills 7.5-minute Quadrangle is located in the Phoenix metropolitan area. The quadrangle is located north of downtown Phoenix and is bordered by Paradise Valley to the north and east, and the Phoenix Mountains to the south (Figure 1). The quadrangle is bounded by latitudes 33°37'30"N and 33°45'00''N, and longitudes 112°00'00"W and 112°07'30"W. The area south of the Union Hills has become highly urbanized during the last few decades and is still undergoing rapid population growth. Thus, the knowledge of the distribution and character of bedrock and surficial deposits is important to make informed decisions concerning management of the land and its resources. Geologic mapping of the Biscuit Flat Quadrangle is related to other 1:24,000 scale mapping projects in and around the Phoenix metropolitan area (Figure 1; see map plate). Geologic mapping of bedrock in the quadrangle was based on field mapping, whereas surficial mapping was based upon field observations, and the interpretation of aerial photographs and soils maps. The respective mapping coverage accomplished by each author (i.e., Holloway and Leighty) is shown on the map plate. A limited amount of unpublished Arizona Geological Survey mapping (by Steve Reynolds and Mike Grubensky for the Phoenix North 1:100,000 scale geologic map) augmented the new mapping of this report. Also, the 1 :24,000 scale mapping of Tertiary rocks by Jagiello (1987) is locally similar to that of this report. Aerial photography includes a series of black-and-white, 1 :20,000-scale (dated 1-19-70) and 1 :40,000 scale (dated 9-6-92) photos. Soil information was compiled from USDA Maricopa County soil surveys (Hartman, 1977; Camp, 1986). This project was supported by the Arizona Radiation Regulatory Agency, with funds provided by the U.S. Environmental Protection Agency through the State Indoor Radon Grant Program. Geologic map of the Union Hills 7.5' Quadrangle, Maricopa County, Arizona - report and one map sheet, scale 1:24,000

The Picacho Mountains are north-south trending mountain range completely surrounded by Quaternary alluvium, and consists of Tertiary and older granitic and gneissic rocks (Figure 1). Picacho Peak, located south of the south end of the range, is also surrounded by alluvium, and consists of Tertiary andesitic volcanic rocks. Picacho Peak and the Picacho Mountains are separated by a gap of shallowly buried bedrock through which pass Interstate 10, the Southern Pacific Railroad, and the Central Arizona Project canal. The Picacho Mountains consists of a compositionally diverse suite of Tertiary, Cretaceous or Proterozoic granitoids, heterogeneous to gneissic granite, muscovite granite, schist, and gneiss, much of which has been affected by middle Tertiary mylonitic deformation and probably by late Cretaceous synplutonic deformation [Rehrig, 1986]. Mylonitization is inferred to have accompanied normal faulting and ascent of the bedrock from mid-crustal depths in the footwall of a moderate to low-angle normal fault commonly known as a "detachment fault". Older gneissic fabrics may record Laramide mid-crustal deformation, or relict Proterozoic fabric. The crystalline rocks of the Picacho Mountains are part of the footwall of a south- to southwest-dipping detachment fault that is exposed in only one small area in the southern Picacho Mountains. Picacho Peak, which consists almost entirely of northeast-dipping basaltic and andesite volcanic rocks, is part of the hanging wall of the detachment fault. Geologic map of the Picacho Mountains and Picacho Peak, Pinal County, southern Arizona - report and two map sheets, scale 1:24,000.

The study area includes the southern Roskruge Mountains and a small area of the northernmost Coyote Mountains in Pima County, southeast Arizona (Figure 1). Elevations in the area range between 2500' and 4300'. The area lies within the sonoran desert with large areas of relatively open desert punctuated by thick brushy zones along major washes. Bedrock geology was mapped by Charles Ferguson and Wyatt Gilbert during the winter and spring of 1999-2000, and the Quaternary geology was mapped by Thomas Biggs and Phil Pearthree in the spring and summer of 2000. Some areas within the boundary of the Tohono O'Odham Nation were mapped using remote techniques. Geologic Map of the Southern Roskruge Mountains (the San Pedro and the southern half of La Tortuga Butte 7.5' Quadrangles), Pima County, Arizona Report and two map sheets, map scale 1:24,000.

Preliminary geologic map of the Oak Creek Ranch 7.5' Quadrangle, Gila County, Arizona. Map scale 1:24,000.

Preliminary geologic map of the Parallel Canyon 7.5' Quadrangle, Gila County, Arizona. Map scale 1:24,000

Preliminary geologic map of the Young 7.5' Quadrangle, Gila County, Arizona - one map sheet, map scale 1:24,000.

Preliminary geologic map of the Salt River Peak 7.5' Quadrangle, Gila County, Arizona - one map sheet, map scale 1:24,000.

Preliminary geologic map of the Meddler Wash 7.5' Quadrangle, Gila County, Arizona - one map sheet, scale 1:24,000.