Sandstone hosted uranium deposits of the Great Divide Basin, Wyoming, USA

The Great Divide basin is located in the southern part of the state of Wyoming in USA. Wyoming is the second largest uranium province in that country after the Colorado Plateau. The Great Divide basin represents an intermontane depression of Tertiary age surrounded by major structural uplifts composed of Precambrian rocks including uraniferous Precambrian granite. The main uranium resources of the Great Divide basin are hosted in the weakly lithified sandstone of the Eocene Battle Spring Formation which terminates the sedimentary sequence at the basin. Uranium occurs in the form of rolls and the tabular mineralisation is usually associated with carbonaceous debris in the host sediments. Because of close spatial relationships between uranium and detrital carbonaceous debris the uranium mineralisation of the Great Divide basin is referred to as detrital carbon-uranium roll-type which is a special class of Phanerozoic sandstone hosted uranium deposits. The deposits of the Great Divide basin contain from 2 to 15 kt of U3O8 each, which occurs as uranium rolls and tabular mineralisation, some of which is fault controlled. Their formation is related to multi-episodic uplifts of the Precambrian basement which is exposed along the margins of the basin.