From abstract: Between mid-May and late June 1976, 3409 water and water-transported sediment samples were collected from 1781 locations spread over an approximate 17 000 kilometer area of northwestern Montana. All of the samples were analyzed for total uranium at the LASL, using standardized procedures and rigorous quality controls--the waters by fluorometry and the sediment (and those waters with >10 parts per billion uranium) by delayed-neutron counting methods.

The objective of the study was to evaluate the favorability for potential uranium resources in Tertiary and related strata. Past studies indicate that the Tertiary basins in southwestern Montana are worthy of further investigation because (1) several basins contain a thick sequence of continental sedimentary rocks, (2) several basins are near possible granitic source rocks that have known uranium occurrences, and (3) some of the Montana basins are geologically similar to basins in Wyoming that are host to important sandstone-type deposits. This study focuses on sedimentary rocks of Tertiary age, but includes some rocks of Late Cretaceous and Pleistocene ages. In some areas only a portion of the total Tertiary sedimentary section could be studied because of poor surface exposures and limited subsurface information.