Selected papers on uranium deposits in the United States

Abstract

Uranium deposits in the United States may be grouped as: (1) deposits with structural control, and (2) deposits with stratigraphic control. The deposits with structural control include veins, breccias, and pipes; disseminated deposits associated with fractures; pyrometasomatic deposits; and pegmatites. The deposits with stratigraphic control include (1) phosphates, carbonaceous shales, and lignites; (2) limestone and dolomite; (3) deposits of the carnotite type; and (4) surficial or caliche deposits. Most of the known uranium deposits are in the western United States. Arizona, Utah, and Colorado contain the largest number of deposits. The deposits with structural control, except the uraniferous pegmatites, are commonly in or related to igneous rocks of post-Cretaceous age, and many of them are associated with Tertiary volcanic rocks. Notably few deposits are genetically related to pre-Cambrian rocks and to Jurassic intrusives. The pegmatite deposits of the western United States are believed to be pre-Cambrian; those of the eastern United States are post-Devonian. Carbonaceous shales, phosphates, and lignites are restricted, for the most part, to terranes of Paleozoic and Tertiary age. Most of the carnotite-type deposits are in sedimentary rocks of Mesozoic age, and the most productive deposits are in rocks of Jurassic age. Study of the distribution of known deposits indicated that the principal favorable areas for further prospecting are those in or near Triassic and Jurassic sedimentary rocks and Tertiary igneous rocks.