Color copies of photomicrograph figures that accompany a report studying uranium in granites in the southwestern United States.

Abstract: Field and laboratory study of primary sedimentary features of the Salt Wash sandstone was undertaken to learn if these structures can be of use in finding hidden deposits of ore and also if they have influenced the localization of either individual ore deposits or larger mineralized districts.

Abstract: The objectives of this study have been to determine the nature of the major fracture pattern of the Zuni uplift; to analyze this pattern for evidence of the mode of origin of the uplift; and to compare the fracturing in the ore areas with that elsewhere on the uplift to see whether diagnostic features exist hat might make it possible to indicate other favorable areas.

Objectives: The purpose of this project was to study in detail the factors controlling the formation of fractures and the fracture pattern actually developed in an area transitional between Colorado Plateau and Basin and Range type structures.

Abstract: Horse Mesa is in the Navajo Indian Reservation directly on the Arizona-New Mexico state line. Uranium-vanadium deposits in the Salt Wash sandstone which caps the Mesa are fairly widespread and small tonngges have been shipped from two mines. The deposits lie 60 to 75 feet above the base of the Salt Wash formation and possibly trend northwest parallel to ore trends on King Tutt Mesa, a mile northeast. Carnotite and vanoxite are the principal ore minerals. About 6,000 feet of wagon drilling is recommended to test two favorable areas. Continued exploration should be governed by results of this first stage drilling.

Introduction: This report is a brief review of the uranium and/or vanadium mining in the eastern Carrizo Mountains, San Juan County, New Mexico and Apache County, Arizona. It was prepared at the request of the Navajo Tribe, the New Mexico Energy and Minerals Department, and the Arizona Bureau of Geology and Mineral Technology. As this report deals only with historical production data, the reader is referred to reports by Blagbrough and Brown (1955), Masters and others (1955), and Stokes (1951, 1954) for descriptions of the geology and ore deposits. Figure 1 shows the locations of the mines and the production is summarized in Table 1 and Figure 2. A separate report (Chenoweth and Learned, 1980) covers the production history of the northern and western Carrizo Mountains.

From introduction: A rapid appraisal of the carnotite resources of the Salt Wash sandstone member of the Morrison formation in the Carrizo Mountains area was undertaken by the U. S. Geological Survey late in 1951 in connection with its current project of geologic mapping of the area. Though brief and preliminary, this report provides a summary of production trends and estimated reserves in the area and indicates as far as possible the total potential of the area as a source of uranium. This information may be helpful in planning new milling facilities or other measures to encourage a higher rate of production.

From objective and plan: The airborne data gathered were reduced using ground-based computer facilities to give the basic uranium, thorium and potassium equivalent gamma radiation intensities, ratios of these intensities, aircraft altitude above the earth's surface, total gamma ray and earth's magnetic field intensity, correlated as a function of geologic units indicated from available geologic maps. Results of analyses of these field data are presented as profile plots of the gamma radiation and earth's magnetic field.

From introduction: This volume contains information and survey results pertaining specifically to the Saint Johns NTMS 1:250,000 scale Quadrangle, Arizona and New Mexico, one of a group of 12 such quadrangles in Arizona, Idaho, Montana, New Mexico, South Dakota, and Washington included in an aerial radiometric and magnetic reconnaissance survey. General information concerning the instrumentation and methods used in data acquisition, processing, and interpretation is presented in Volume 1 of this final report.

The airborne data gathered were reduced using ground-based computer facilities to give the basic uranium, thorium and potassium equivalent gamma radiation intensities, ratios of these intensities, aircraft altitude above the earth's surface, total gamma ray and earth's magnetic field intensity, correlated as a function of geologic units indicated from available geologic maps. Results of analyses of these field data are presented as profile plots of the gamma radiation and earth's magnetic field.

From Operational Program: This final report includes a general geologic description of the area, including descriptions of the various geologic units and correlates the airborne data to the geologic units as provided by the geologic maps. Also included is a frequency distribution study of the data as a function of the geologic units encountered over the NTMS area including the tie line data.

This report contains aerial radiometric and magnetic survey data for Tularosa National Topographic Map of New Mexico.

From introduction: To improve understanding of uranium mineralization of the Todilto Limestone of Late Jurassic age in the Grants district, New Mexico, the mines active in 1957 were reviewed to determine the major types of deposits. A representative example of each type was selected and mapped in great detail to establish a prototype. It was hoped that the analysis of prototypes might shed considerable light on the mineralization process and aid evaluation of other deposits by offering a standard of comparison.

This report is an issue of the original draft copy of the "Interim Staff Report on Uranium Exploration on the Colorado Plateau", dated June 1951. The original draft copy was only recently located and is being published at this time because of the interest in the contained historical content.

The tabulations on these pages include all of the known areas in Colorado, Utah, New Mexico, and Arizona having economically important uranium-vanadium deposits of the type which are generally referred to by the terms roscoe-lite and/or carnotite. Though similar deposits are known to exist in other areas they are to be viewed as being little more than mineralogical curiosities.

Although uranium gas first discovered in the Carrizo Mountains area in 1918, the ores were not developed until 1942. They have, however, been mined continuously since that time. Formations in the area range from the Pernian Cutler through the Cretaceous Mancos shale, and all are intruded by a dioritic laccolith and its related dikes. The older structures, which include the Defiance Uplift, the San Juan Basin, and the Four Corners Platform are somewhat disrupted by the effects of the intrusion. A number of mines are described and mineralogical and geochemical studies made are outlined. The primary uranium mineral is unknown, but the chief uranium ore-mineral is the secondary mineral, tyuyamunite. It is concluded that there is at least minor structural control of the ore bodies along sedimentary trends and joints, and that all ore bodies of 500 tons or more are on the Defiance monocline or its extensions. The uranium may have been syngenetic in the sediments, and redistributed by solutions or, more likely, that it rose vertically in hydrothermal solutions from the local intrusive bodies.

From Purpose, Scope, and Methods: The objective of this study was an evaluation of resources of the Carrizo Mountains area. Four factors: distribution of ore bodies, relation of uranium to the host rock, relation of ore to structure, and circumstances that might precipitate uranium were studied in search of data bearing on manner of distribution of ore, the time and causes of deposition, and the probable source of the uranium-bearing solutions.

Abstract: Ten days were spent during June 1955, examining the sedimentary rocks along the San Juan and Colorado Rivers between Mexican Hat, Utah, and Lee's Ferry, Arizona. The most favorable area for uranium deposits occurs in the Shinarump member of the Chinle formation between Clay Hills Crossing and Spencer Camp along the San Juan River. Mineralization is spotty and deposits are small and almost all below ore-grade. Only one small mine, the Whirlwind, is currently producing ore. Gray-green alteration of the underlying Moenkopi is moderately developed in the vicinity of the Whirlwind mine; elsewhere alteration is weakly developed.

From abstract: The Carrizo Mountains vanadium district is in the Navajo Indian Reservation, northeastern Arizona and northwestern New Mexico. From May through October, 1942, two mining companies, operating under lease agreements with the Navajo Service, opened several mines in the district and produced a total of about 6,000 tons of ore, averaging approximately 2.2 percent.

Introduction: Vanadium ore is being mined at many places in western Colorado, southeastern Utah, northeastern Arizona, and northwestern New Mexico (fig. 1). Eight mills in this region produced about 4,300,000 pounds of V2 05 in 1942, representing about 90 percent of the vanadium obtained from domestic sources. Although ore production has mostly exceeded mill capacity since 1937, production during the last half of 1942 averaged only about 19,000 tons or ore a month, whereas the capacity of these mills total about 22,000 tons a month. At the expected rate of ore production, ore stockpiles will be exhausted sometime in 1944, and these mills will then have excess capacity. With more intensive prospecting than now practiced, however, it is believed that sufficient reserves can be indicated to sustain capacity operation of these mills for several years. This memorandum is prepared to specify those areas that are considered most favorable from a geologic standpoint for developing large reserves of vanadium ore by prospecting. It is based on intensive studies by the Geological Survey since 1939 in most of the areas that produce vanadium ore.

From introduction: The general distribution of known deposits of vanadium-bearing sandstone, which also contain some uranium and radium, is shown in figure 1 1/ and Exhibit A, plate 53. 2/ During 1939-41 the Geological Survey made detailed geological studies of these deposits in the Uravan district, Montrose County, Colorado, as well as preliminary examinations in other parts of the Colorado Plateau vanadium region. In 1942 detailed geological studies were made o the deposits in the Egnar-Slick Rock district, San Miguel Co., Colo.; 3/ the Carrizo Moungains district, Navajo Indian Reservation, Arizona and New Mexico; 4/ the Placerville district, San Miguel County, Colo. 5/ and the Monticello district, San Juan Co., Utah. 6/ Since May 3, 1943, the Gelogical Survey has guided the Bureau of Mines program of prospecting these deposits in parts of Colorado and Utah.

From introduction and acknowledgements: This report is written to supplement and complete the record contained in some fifty district and special reports already submitted, and duplication of material in district reports has been studiously avoided. The data herein contained are largely of a regional type, inclusion of which was not wholly appropriate to the district reports.

Three formations in the Tertiary of the San Juan Basin were investigated for their uranium favorability. They are the Ojo Alamo Sandstone, the Nacimiento Formation, and the San Jose Formation. The study comprised a literature survey and a basin analysis, which consisted of subsurface lithofacies, stratigraphic, and radiometric mapping. Field work in preparation for the subsurface analysis consisted of examination of outcrop and measured sections, surface radiometric traverses, and checking of reported surface radioactive anomalies.

As part of the LASL portion of the US EROA NURE program, water samples from 534 locations and sediment samples from 2936 locations were taken over a 7770 square kilometers area of the Estancia Valley in 1975 and analyzed for uranium.