The Robinson and Weatherly uraniferous pyrobitumen deposits near Placerville, San Miguel County, Colorado

Abstract

20 Analyses of samples from the Robinson property, San Miguel County, Colorado. • .. o • • • 0 0 0 0 0 0 o 0 o o • o o o o o 30 Detatled stratigz;aphic section of the Dolores formation a~ the Weatherly property , San Miguel County, Colorado • 0 0 0 40 Analyses of samples from the Weatherly property, San Miguel County, Colorado o • o o o o 0 •. • • o 0 0 • o o • o o o ., o • 50 Semi-quantitative spectrographic analyses of sele. cted pyrobitumen specimens, Weathedy property, San Miguel County, Colorado

Geology of epigenetic uranium deposits in sandstone in the United States

“…Uranium minerals ---------------- Sources of data Fischer and others (1947). Hess (1913); Wilmarth and Vickers (1953); Rosenzweig and others (1954); Bush and others (1959). Moorehouse (1951) : Frondel (1958) p. 28); others (1959 .…”

Reconnaissance for radioactivity in the metal-mining districts of the San Juan Mountains, Colorado

“…A few of the smaller mining districts, the vanadium-uranium deposits in Mesozoic sedimentary rocks on the west and southwest borders of the mountains (Fisher, Haff, and Rominger, 1947;Bush and Bryner, 1953), and the uranium-bearing hydrocarbon deposits in the Placerville area west of Telluride (Wilmarth and Vickers, 1953) were not examined. Results of work in areas 1 through 7 (fig.…”

Uranium in the metal-mining districts of Colorado

“…The country from La Veta Pass, Huerfano County, northward to South Park (Gott, 1951) and eastward to Colorado Springs ) contains a number of small carnotite deposits in Pennsylvanian, Permian, and Jurassic sandstones, and further search may uncover larger and richer deposits. The Placerville district, San Miguel County, well known for its roscoelite ores in the Entrada sandstone (Fischer, Haff, and Rominger, 1947), also contains veins with uraniferous hydrocarbons and sulfides that cut the sedimentary rocks below the Entrada sandstone (Hess, 1913;Wilmarth, 1951). In the Skull Creek area, Moffat County, small cupriferous carnotite deposits occur in sandstones of Mesozoic age.…”

“…Polymineralic-hydrocarbon veins in the Placerville district contain galena, sphalerite, erythrite, tetrahedrite, molybdite, chalcocite, azurite, and malachite in a gangue of calcite andbarite. The uranium is in a solid hydrocarbon, perhaps thucholite, that forms rounded to irregular masses as much as 6 inches across in the veins andadjacent limestone (Wilmarth, 1951).…”