Previous workers have established the general petrological character of the McCoy Mountains Formation and equivalent Jurassic-Cretaceous units in southwestern Arizona and southeastern California by point-counting the detrital modes of 170 sandstones and metasandstones (Robison, 1979; Harding, 1980, 1982; Harding and Coney, 1985; Laubach et aI., 1987; Richard et aI., 1987; Fackler-Adams et aI., 1997). Many of the samples studied, however, are foliated to varying degrees, with neomorphic growth of metamorphic minerals partly obscuring detrital textures and compositions. For this report, a set of control samples was collected from the least deformed and least altered rocks that could be found exposed in mountain ranges of southwestern Arizona.

Beginning in the mid-1860s the southwestern US experienced a mining boom, and a large number of mines were developed. They went through alternating phases of economic upswing and decline, but by the end of the 1940s most of the smaller mines had been abandoned for good (Woznicki 1987, Beck and Haase 1989). Nevertheless, their tailing, waste rock dumps and acid mine drainage still represent an environmental hazard because of the heavy metals released from them (Young and Clark 1978, Marcus 1987, Rampe and Runnels 1989, Rosner 1995a, 1996, 1998, Graf et al. 1991, Hyde 1994, Lind and Hem 1993). The metals can either be leached directly into the groundwater and the surface water (Young and Clark 1978, Lind and Hem 1993) or accumulate in soils and sediments (Brummer et al. 1986, Bradley 1989, Moore and Luoma 1990, Schachtschabel et al. 1992). Under certain circumstances they can be redissolved and become available to plants or enter the groundwater with the percolation water (Young and Clark 1978, Bergmann 1989, Herms 1989, Sauerbeck 1989). This article will deal only with heavy metals in fluvial sediments and in soils; the contamination of water and vegetation in the study area (cf. below) was dealt with in recent publications (Rosner 1995b, 1996, 1998).

Groundwater and surface water quality was analyzed in several watersheds of the historic mining district of Chloride and the southern adjacent former mining areas on the western slope of the Cerbat Mountains, northwest of Kingman, in Mohave County, Arizona. The investigations were carried out to characterize the general water quality, and particularly to ascertain, to what degree groundwater and surface water are contaminated due to the past mining activities. Groundwater in the immediate vicinity of the large Tennessee Mine, where ore processing took place, was found to be seriously polluted by heavy metals. But neither the groundwater in the town of Chloride, nor the groundwater in the Cerbat Wash watershed, showed evidence of contamination by subsurface or surface water flow from the upstream mining areas. Independent of the historic mining nitrogen contamination was found in the Chloride wells, which could be attributed to improperly functioning private septic tanks. In contrast to the groundwater almost all surface waters were contaminated by heavy metals and other contaminants due to the historic mining activities.

Geologic Map of the Salome 30' x 60' Quadrangle, West-central Arizona. One map sheet and one report (33 pages).

Land subsidence and related earth fissures have become widespread occurrences in southern Arizona. As the areal and vertical extent of subsidence has increased, more earth fissures have been discovered. As a result, there is growing concern about existing and potential damage caused by these phenomena. This concern is reflected by the increasing number of requests for information received by the Arizona Geological Survey (AZGS), which has prompted the compilation of this bibliography, establishment of a Steering Committee on Subsidence and Earth Fissures, and formation of the Center for Land-Subsidence and Earth-Fissure Information (CLASEFI), which is supported jointly by the AZGS and the Arizona Department of Water Resources. Although many human-induced and natural processes give rise to land subsidence and earth fissures, those in southern Arizona are closely linked to long-term extraction of ground water by man. This bibliography, therefore, focuses on subsidence resulting from ground-water withdrawal. As ground water is removed from some alluvial aquifers, sediment particles in those aquifers lose some of their ability to support the overburden, the grains become more closely packed, and aquifer volume decreases. The land surface sinks (subsides) in response to the decreased aquifer volume at depth. This type of subsidence proceeds gradually, but, with time, can spread over large areas and cause significant deformation. ( 21 pages)

This report is a compilation of available data on Quaternary faults in Arizona as of the summer of 1998. These data were compiled as part of a effort to compile data and map information on Quaternary faults throughout the world, which is being overseen by Michael Machette of the U.S. Geological Survey. Michael Machette, Richard Dart, and Kathleen Haller provided substantial technical assistance in the preparation of these data, and the fault data forms were reviewed and edited by Michael Machette. As part of this effort, fault traces were entered into a Geographic Information System (GIS) database by the USGS. Map traces were plotted on 1:250,000-scale topographic base maps, and were digitized by Richard Dart and Lee-Ann Bradley of the USGS. They generated the 1:750,000-scale fault map that accompanies this database. neotectonic structures in Arizona. The first and most comprehensive of these is the state-wide compilation of neotectonic faults by Menges and Pearthree (1983), which was done primarily by Chris Menges. I also utilized the later state-wide compilation of young faults by Euge and others (1992). Regional compilations of the Douglas and Silver City 1:250,000-scale quadrangles in southeastern Arizona by Machette and others (1986) and the Flagstaff area by Pearthree and others (1996) provided most of the data for these areas. I also utilized indexes of geologic mapping in Arizona (Scarborough and Coney, 1982; Harris and others, 1994) and the geologic bibliography for the state (Trapp, 1996) developed by the Arizona Geological Survey. The data structure is set up to provide systematic information on each fault zone. Each fault has been assigned a number as part of the world-wide fault data set; faults are identified by number on the accompanying map. Fault names are based on published maps or reports. In cases where different names have been used for the fault, the alternative names are listed within the database. All of the faults are listed by name and number in the table on the following page. This table indicates where the data summary for each fault can be found, as well as the age of youngest activity and fault slip rate category. The individual fault data sheets include information on map and data sources, fault location, geologic setting of the fault, the geomorphic expression of the fault, recency of fault movement, fault slip rate(s), and fault zone length and orientation. Fault locations are rated good if they were originally mapped at 1:62,500 scale or larger, moderate if they were mapped at 1:130,000 scale or larger, or poor if there is substantial uncertainty in their location because of weak surface expression. Faults were grouped into slip rate categories of <0.02 mm/yr, < 0.2 mm/yr, and <1 mm/yr. Reported lengths are for the whole fault zone, not cumulative length of each individual fault in the zone, and orientations are averages for the fault zone. A composite list of references is at the end of this report. These fault data can be readily updated. Any feedback or any further data regarding individual faults is welcome, and more faults can be added as they are identified. (122 pages)

We have completed initial paleoseismologic investigations to evaluate the recency and size of paleoearthquakes and long-term slip rates on the Hurricane fault in southern Utah and northern Arizona (SUNA). The Hurricane fault is a long, west-dipping normal fault with substantial late Cenozoic displacement within the structural and seismic transition between the Colorado Plateau and the Basin and Range province. Previous reconnaissance studies of the fault in northern Arizona and southern Utah had documented evidence of late Quaternary activity. Because of its great length, the Hurricane fault almost certainly ruptures in segments, and abundant geometric and structural characteristics suggestive of fault segmentation exist along its trace. Our efforts have focused on a systematic, detailed reconnaissance of the fault from the Utah-Arizona border north to Cedar City and a detailed investigation of 20 km of the fault from the border southward into Arizona. In addition, we conducted detailed reconnaissance investigations of the fault in Whitmore Canyon north of the Colorado River. ( 137 pages)

Karst is the name applied to topography that develops on land underlain by soluble rocks such as limestone, gypsum, and salt. Karst terrain is characterized by solution features such as caves, sinkholes, depressions, enlarged joints and fractures, and internal drainage. The name was derived from the Karst region of Slovenia (part of the former Yugoslavia), which is underlain by limestone. This report summarizes the occurrence of karst features on the Colorado Plateau of Arizona. The first section briefly discusses the three major types of karst features on the Plateau: breccia pipes, surficial karst, and deep-seated salt karst. The remainder of the report focuses on salt karst in the Holbrook basin.

In the past decade, military and economic pressures have greatly accelerated research in the field of physical metallurgy. As a result, many uses have been found for elements which hitherto were considered laboratory curiosities, and now some of these minor metals are of strategic importance. This newly-created demand has prompted the extractive metallurgist to devise methods of recovering these elements and to determine which raw materials are the best sources. In some cases the prospector finds deposits which, because of size or some other favorable factors, may encourage the chemist and metallurgist to work out new recovery and refining methods, although the usual role of the prospector is to search for deposits of material already in demand. In any event, the prospector should know what substances to seek, some of the important characteristics of those substances, how they occur geologically, and what tests can be used to determine their presence. The lack of uses developed for the strategic minor metals until recently is a direct reflection of the rarity of known important deposits of these metals. If relatively large, rich deposits of them had been known in the past, there is little doubt that the metals would long since have been put to use. Another factor which delayed the utilization of the strategic minor metals is the difficulty with which many of them are separated from their impurities. The difficulty of separation gives rise to another problem as far as the prospector is concerned; that is, the identification or testing for these metals. With the exception of two or three of them, there are no satisfactory field tests that can be used. Most of the strategic minor metals occur in very minor concentrations and bear marked chemical similarity to other, more abundant elements; hence their detection by chemical methods necessarily involves the use of elaborate, time-consuming and expensive laboratory procedures.

Deposits of pegmatite minerals are known from many parts of Arizona, and from time to time efforts have been made to develop some of them as commercial sources of feldspar, quartz, mica, beryl, lithium minerals, tungsten minerals, tantalum-columbium minerals, and other salable commodities. The pegmatites occur mainly in terranes or relatively old, crystalline rocks that appear within the Mexican Highland and Sonoran Desert portions of the state. These physical divisions of the Basin and Range province extend southeasterly from the Colorado River to the southern and eastern borders of the state, and lie southwest of the broad Colorado Plateau province (Fig. 1). Most of the largest and best known deposits lie within the so-called Arizona pegmatite belt, which is about 250 miles long, 30 to 80 miles wide, and extends south-southeastward from Lake Mead through parts of Mohave, Yavapai, Yuma, and Maricopa counties to points south of Phoenix (Fig. 1). The mine and mill of the Consolidated Feldspar Corporation, a few miles northeast of Kingman in the northern part of the pegmatite belt, represent by far the largest and longest-lived of the commercial operations for pegmatite minerals. A production of more than 100,000 tons of crude and ground feldspar has been obtained during the past three decades, and future operations should contribute substantially to this total. Both feldspar and ceramic-grade quartz have been taken from other deposits in the belt, but on a considerably smaller scale. Some sheet mica was produced during World War II from the Mica Giant pegmatite, southeast of Kingman, and modest amounts of scrap mica have been mined over a long period of years from other properties in the Hualapai Mountains, as well as from pegmatites north of Chloride, in central western Mohave County; others in the Weaver, Bradshaw, and Wickenburg Mountains of southern Yavapai County; and from still others in various parts of Maricopa County.