Introduction: This report presents the results of a subsurface uranium favorability study of the Morrison Formation in southwestern Colorado and southeastern Utah. The project began November 1, 1974 and was concluded April 11, 1975. The study was carried out under the auspices of the Grand Junction Office of the Energy and Research Development Administration (ERDA).

From purpose and scope: The purpose of the National Uranium Resource Evaluation (NURE) program of the U.S. Department of Energy (DOE) is to identify and delineate areas and environments within the Aztec 10X20 Quadrangle, New Mexico and Colorado, that exhibit characteristics favorable for the occurrence of uranium deposits that have the potential to contain at least 100 metric tons U3 08 total endowment with a minimum grade of 100 ppm (0.01 percent) U3 08 . Evaluation is based on geochemical, mineralogic, hydrologic, aerial radiometric, sedimentologic, and general geologic characteristics of the formations in the quadrangle.

From purpose and study: The Durango Quadrangle, southwest Colorado (Fig. 1), was evaluated to identify geologic units and to delineate areas that exhibit characteristics favorable for uranium deposits. Geologic environments were evaluated to a depth of 1500 m based on recognition criteria (Mickle and Mathews, eds., 1978) prepared for the National Uranium Resource Evaluation (NURE) program. A favorable environment, as defined for this program, is an environment that could contain at least 100 tons U308 in deposits with an average grade no less than 100 ppm U308 . Environments that did not meet the NURE criteria were categorized as unfavorable. Some of the subsurface and several areas of restricted access were categorized as unevaluated because insufficient data exist for proper evaluation.

Abstract: Uranium resources of the Lamar Quadrangle, Colorado and Kansas, were evaluated using National Uranium Resource Evaluation criteria. The environment favorable for uranium is the Lower Cretaceous Dakota Sandstone in the area east of John Martin Reservoir for south Texas roll-type sandstone deposits. Carbonaceous trash and sulfides are abundant in the Dakota Sandstone. The unit underlies a thick Upper Cretaceous section that contains bentonitic beds and uraniferous marine black shale. Water samples from the Dakota Sandstone aquifer contain as much as 122 parts per billion Uranium-3 Oxygen-8. Geologic units considered unfavorable include most of the Paleozoic rocks, except in the Brandon Fault area; the Upper Cretaceous rocks; and the Ogallala Formation. The Dockum Group, Morrison Formation, and Lytle Member of the Purgatoire Formation are unevaluated because of lack of data.

From Introduction: "The Montana Quadrangle of the National Topographic Map Series (NTMS), scale 1:250,000, in west-central Colorado was evaluated for geologic environments favorable for uranium deposits."

From Introduction: "The Rawlins Quadrangle (2º) is in south-central Wyoming and extreme northwest Colorado (Fig. 1). Evaluation of the quadrangle was conducted to identify and delineate areas that contain environments exhibiting characteristics common to known uranium-bearing environments."

From Introduction: "The Trinidad Quadrangle, Colorado, was evaluated to identify geologic units and to delineate areas that exhibit characteristics favorable for the occurrence of uranium deposits. All geologic environments were evaluated by means of surface investigations and subsurface data to a depth of 1500 m."

From Purpose and Scope of Study: "The purpose of this study is to provide an evaluation of the favorability of the Vernal, Colorado-Utah, 1º x 2º Quadrangle (Fig. 1) for the occurrence of uranium deposits. The study restricted to indicating geologic units and areas favorable for uranium deposits containing at least 100 tons of U3O8 with an average grade of .01 percent U3O8 or more and less than 1,500m (5,000 ft) deep."

From Introduction: "The purpose of the National Uranium Resource Evaluation (NURE) program of the U.S. Department of Energy (DOE) is to identify and delineate areas and environments with the Shiprock 1ºx2º Quadrangle, New Mex., Ariz., Colo., and Utah, that exhibit characteristics favorable for the occurrence of uranium deposits that have potential to contain at least 100 metric tons U3O8 total endowment with an average minimum grade of 100 ppm (0.01 percent)."

From Introduction: "The Leadville Quadrangle, Colorado (Fig. 1), was evaluated to identify and delineate areas and geologic units that exhibit characteristics favorable for the occurrence of uranium deposits. Geologic environments were placed into one of three categories--favorable, unfavorable, or unevaluated--based on National Uranium Resource Evaluation (NURE) program."

From Introduction: "The purpose of this study is to provide an evaluation of the favorability of the Craig 1º x 2º Quanrangle, Colorado (Fig. 1) for the occurrence of uranium deposits."

From Introduction: "The Cortez 1º x 2º Quadrangle, southwestern Colorado and southeastern Utah (Fig. 1), was studied to identify and evaluate areas and geologic formations that are favorable for the occurrence of uranium deposits of specific minimum size and grade."

From Introduction: "The Front Range region from the Wyoming-Colorado state line to southern Colorado is a uranium metallogenic province. Correspondingly, uranium has been discovered in mineable deposits in metamorphic, igneous, and sedimentary rocks formed throughout the geologic history of the region both within the Front Range itself and in the apron of sedimentary rocks that surrounds the Front Range. The Pueblo 1ºx2º National Topographic Map Series (NTMS) quadrangle, Colorado (Fig. 1), which lies within this uranium metallogenic providence, was evaluated to identify and delineate areas and geologic units that exhibit characteristics favorable for the occurrence of uranium deposits."

Abstract: Eleven areas have been identified in the Greeley 1° x 2° Quadrangle, Colorado, that appear to be favorable for the occurrence of uranium having a minimum of 100 tons of U₃O at grades of 0.01 percent or better. Nine of these are in the Front Range metamorphic and igneous environment, and two are in the Great Plains sedimentary environment. The two favorable areas in the Plains are underlain by the Fox Hills and Laramie Formations and are favorable for "Texas" roll-type (Subclass 242) and "Wyoming" roll-type (Subclass 241) deposits. These two favorable areas have a combined area of approximately 7000 km², and they appear to have the greatest potential for uranium ore production of all the identified favorable areas. In the Front Range, the Jamestown district has a record of past uranium production and has the highest probability among the favorable areas in crystalline rocks of containing a minimum endowment of 100 tons U₃O at 0.01 percent or better. Known deposits and expected resources in the Jamestown district belong to the magmatic-hydrothermal class (Class 330), or to the autometasomatic class (Class 350), with perhaps some enrichment resulting from supergene processes (Class 360, authigenic, and Class 370, allogenic). The Log …

From Introduction: "The La Junta Quadrangle, Colorado and Kansas (Fig. 1), was evaluated to identify and delineate areas and geologic units to a depth of 1500 m (5,000 ft) that exhibit characteristics favorable for the occurrence of uranium deposits, which could contain at least 100 tons U3O8 and have an average grade of not less than 100 ppm U3O8."

From Introduction: "The Moab 1ºX2º Quadrangle, east-central Utah and west-central Colorado (Fig. 1) was studied to identify and evaluate areas and geologic formations that are favorable for the occurrence of uranium deposits of specific minimum size and grade."

From Purpose and Scope: "The Raton Quadrangle, New Mexico and Colorado (Fig. 1), was evaluated to identify geologic units and delineate areas that exhibit characteristics favorable for uranium deposits. All geologic environments exposed at the surface were considered. In the subsurface, all geologic environments to a depth of 1500 m were considered using either projection of findings for outcrops or subsurface information from borings."

Appendices containing data on uranium availability in the Moab Quadrangle to accompany a report on U.S. uranium resources in Colorado and Utah.

Appendices containing data on uranium availability in the Greenly Quadrangle to accompany a report on U.S. uranium resources in Colorado.

Appendices containing data on uranium occurrences and analyses from the Lamar Quadrangle, in addition to petrographic descriptions of samples.

Appendices containing data on uranium occurrences in the Pueblo Quadrangle to accompany a report on U.S. uranium resources in Colorado.

Appendices containing data on uranium availability in the Cortez Quadrangle to accompany a report on U.S. uranium resources in Colorado and Utah.

Appendices containing data on uranium availability in the Shiprock Quadrangle to accompany a report on U.S. uranium resources in New Mexico, Arizona, Colorado, and Utah.

Appendices containing data on uranium availability in the Aztec Quadrangle to accompany a report on U.S. uranium resources in New Mexico and Colorado.