A compilation geologic map of the southwest part of the Tonto National Forest. Included here is the ArcGIS data including shapefiles published as DI-41.

This publication, consisting of four structure and correlation sections across portions of the eastern Mogollon Slope region in east-central Arizona, serves as a companion piece to the Arizona Oil and Gas Conservation Commission subsurface structure maps G-6 (G-6a), G-7, and G-8. It represents an attempt to present graphically structural and stratigraphic information designed to facilitate future investigations of the petroleum potential by industry. PURPOSE AND SCOPE. The principal purpose in publishing the sections is to provide petroleum exploration geologists a graphic presentation of the subsurface stratigraphy and structure revealed by most of the wells penetrating basement rocks in the study area. Because of the widely diverse "picks" of the top of the Pennsylvanian Naco Formation, as reported in published literature and in well completion reports submitted to the Oil and Gas Conservation Commission, emphasis in presenting stratigraphic data on the sections has been placed on the interval from the base of the Fort Apache Member of the Permian Supai Formation to the top of pre-Pennsylvanian rocks. The petroleum potential of the marine carbonates in this interval, in addition to those of the Fort Apache Member of the Permian and pre-Pennsylvanian sections, has not been evaluated adequately in this frontier area.

Pre-Permian strata have been the objective of several oil and gas tests drilled in the eastern Holbrook Basin, Arizona. This has been a reasonable and valid pursuit especially in light of the many shows of oil and gas recorded in pre-Permian units in wells drilled in the eastern Holbrook Basin (Peirce and Wilt, 1970; Conley and Giardina, 1979). Most tests have targeted Devonian rocks, which are strongly petroliferous in outcrop south of the Holbrook Basin along the Mogollon Rim and in Salt River Canyon (Huddle and Dobrovolny, 1952) and contain asphalt in fractures between Payson and Pine (Conley, 1975). Geochemical analysis of Devonian mudstones in Salt River Canyon have a total organic carbon content of 2.81 percent and are within the oil generating window (Desborough, Poole, Daws, and Scarborough, 1984, p. 54). Devonian strata in northeastern Arizona, north of the Holbrook Basin, have produced approximately 100,000 barrels of oil in the Walker Creek Field (Rauzi, 1996). As a result, hydrocarbons may well have been generated in Devonian source rocks at depth in the eastern Holbrook Basin.

Abstract: This map was modified from a map originally included as part of Steve Skotnicki's Ph.D. dissertation at Arizona State University. Purpose: Paul Knauth and his students have studied the cherts within the erosion surface at the top of the Mescal Limestone for many years. Along with Bob Horodyski, Paul co-discovered what may be the oldest known terrestrial microfossils entombed within the chert (Horodyski and Knauth, 1994) and subsequently enlisted Steve to decipher the stratigraphy and petrology of these cherts. The goal was to try to unravel the sequence of events that led to their formation, in an effort to better understand life on land in the Precambrian. As a result Paul helped to support this research during parts of two summers through a NASA Exobiology Grant #NAG5-4060.

The Sierra Ancha are a series of high plateaus, mesas, and ridges that extend from Theodore Roosevelt Lake in the south to the Mogollon Rim on the north. The southern margin is in some paces a steep escarpment or series of escarpments, in part defined by normal faulting and down-dropping of blocks to the south and by relatively little faulting to the north. Faulds (1986) and Potochnik (1996) suggested that the southern margin of the Sierra Ancha is an ancient paleocanyon through which the ancestral Salt River flowed to the east. Deep, narrow canyons separate the mesas. Some of the deeper canyons reveal older, early Proterozoic (~1.7 Ga) metamorphosed sedimentary and volcanic rock and weakly deformed early and middle Proterozoic granitic rocks. However, most of the Sierra Ancha are composed of very weakly metamorphosed to unmetamorphosed, nearly flat-lying sedimentary rocks of the middle Proterozoic Apache Group.

This geologic map was produced to compile and reinterpret published geologic information, and present the result of new geologic mapping in the Ray-Superior area. This data set serves as the basis for ongoing efforts to better understand the geologic history of this area, particularly with respect to the distribution and origin of mineral deposits. This compilation is based on published USGS and Arizona Geological Survey geologic maps of the Picketpost Mountain [Peterson, 1966; Spencer and Richard, 1995], Superior [Peterson, 1969], Pinal Ranch [Peterson, 1963], Mineral Mountain [Theodore et aI., 1978], Teapot Mountain [Creasy et aI., 1983], Sonora [Cornwall et aI., 1971], North Butte [Richard and Spencer, 1997], and Grayback [Cornwall and Krieger, 1975] quadrangles. More detailed mapping by Stan Keith in a strip west from the Ray Mine to the belt of Apache Group strata south of Picketpost Mountain was part of a master's thesis project that was completed as an Arizona Bureau of Geology and Mineral Technology OpenFile Report [Keith, 1983]. Detailed 1: 12,000-scale maps from this report have been generalized as necessary to show at a scale of 1:24,000 for this compilation. Several faults shown in the northern Dripping Spring Mountains, separating Apache Group strata and diabase (Y d), have been inferred from the distribution of units in the Apache group, based on mapping by Cornwall and Krieger [1971]. The geology around the Ray pit is based on Keith [1983], Creasy et ai. [1983], Cornwall et ai. [1971], and John [1994]. A particular problem in this area is the major modifications to the terrane resulting from mining operations. The location of the earth's surface in the mine pit changed significantly between the time Cornwall et ai. and Creasy et ai. did their mapping (1965-1970), Keith did his mapping (early 1980's), and John did his mapping (early 1990's). Because the contour lines on the base map indicate the earth's surface in the early 1960's, east of the Diabase fault, the geology shown is from Cornwall et al. [1971]. The pit limit shown on the map is from John [1994]. Geology west of the Diabase fault and within the 1994 pit limit is from John, and thus is unrelated to the topography shown on the base map. Dumps and tailings now bury large areas adjacent to the pit that were exposures of bedrock when the various maps were made. The patterned area on the base map approximates the area affected by mine operations. The map shows outcrops that are now buried but had previously been mapped within these areas. Compilation Geologic Map of the Ray-Superior Area, Central Arizona Scale 1:24,000