Uranium deposits in the eastern San Juan Basin, Cibola, Sandoval and Rio Arriba Counties, New Mexico

Although the first report of uranium in New Mexico was from volcanic rocks in the Jemez Mountains, very litt le urani um has been produced ( < 20 ,000 lbs of U,0 , ) from the eastern San Juan Basin. Uranium occurs in Morri son Formation sandstones. other sandstones, the Todilto Formation, other sedimentary rocks. epithermal ve ins, and disseminated deposits in igneous and metamorphic rocks. Uranium deposits in the Morrison and Todilto Formations were deposited duri ng the Jurassic, although Tertiary-Quaternary oxidation and remobilization of some deposits may have occurred . Deposits in the Precambrian rocks in the Tusas Mountains are magmatic and related to grani tic and pegmatit ic rocks. Other uranium deposits in the eastern San Juan Basin may have been derived from devitriticat ion and leaching from the Bandelicr Tuff. The potential for nearfutu re development of uranium deposits in th is area is nil because of lack of demand, low uranium prices and low grade . 34 1