Radioactive titaniferous heavy-mineral deposits in the San Juan Basin, New Mexico and Colorado

Upper cretaceous rocks of the San Juan Basin contain titaniferous sandstone deposits as significant as any in the Rocky Mountains. Ilmenite in the deposits is highly altered, and as a result of Fe leaching it contains an increase percentage of TiO/sub 2/. Most of the ilmenite is free from intergrowths with magnetite. Radioactivity, fluorescent zircon, and characteristic sedimentary environment aid in the recognition of new deposits. (J.E.D.)