The geology, carbonaceous materials, and origin of the epigenetic uranium deposits in the Tertiary Sespe Formation in Ventura County, California

Uranium deposits have been known in western Ventura County, California, since about 1959. These epigenetic uranium deposits are found in and are probably derived from the Tertiary Sespe Formation, which is of continental origin. The sandstone-filled paleochannels served as ground-water conduits that carried uranium-bearing solutions to the depositional site. The uranium mineralization took place when the humate was deposited (perhaps near the seashore where terrestrial and marine interacted) or perhaps shortly thereafter