Coal and carbonaceous shale of the Dakota formation of Cretaceous age
were examined for radioactivity in the Colorado Plateau of southwestern
Colorado and northwestern New l1exico during the summer of 1953. Older
and younger sedimentary rocks and some igneous rocks also were examined,
but in less detail, Weak radioactivity was detected at many places but
no new deposits of apparent economic importance were discovered. The
highest radioactivity of carbonaceous rocks was detected in black shale,
siltstone, and sandstone of the Paradox member of the Hermosa formation
of Pennsylvanian age. A sample collected from this member at the Bald
Eagle prospect in Gypsum Valley, San Higuel County, Colo. contains 0.10.
Carbonaceous rocks were investigated at several localities on the
Las Vegas Plateau and the Canadian Escarpment in Harding and San Miguel
Counties, northeastern New Mexico. Carbonaceous sandstone and siltstone
in the middle sandstone member of the Chinle formation of Triassic age
contain uranium at a prospect of the Hunt Oil Company southwest of Sabinoso
in northeastern San Miguel County, N. Mex. A channel sample across 3.2
feet of mineralized rocks at this locality contains 0.22 percent uranium.
Weak radioactivity was detected at two localities in carbonaceous shale
of the Dakota and Purgatoire formations of Cretaceous age.
Additional publication details
USGS Numbered Series
A reconnaissance for uranium in carbonaceous rocks in southwestern Colorado and parts of New Mexico