Uranium mining in Colorado the Slick Rock, Gypsum Valley, Uravan, and Gateway mining districts. Uranium mining in southwest Colorado goes back to 1898, when a miner dug ten tons of yellow ore that tested high in uranium and vanadium out of a deposit at Roc Creek in Montrose County, Colorado, and shipped it to France, where M. M. C. Friedel and E. Cumenge identified the new mineral that they named carnotite. The mineral was mined for its vanadium, with uranium as a byproduct. Although radium had been discovered in 1898, it had been derived from pitchblende, and the radium content of carnotite was not
Uranium–thorium dating Uranium–thorium dating Uranium–thorium dating, also called thorium-230 dating, uranium-series disequilibrium dating or uranium-series dating, is a radiometric dating technique established in the 1960s which has been used since the 1970s to determine the age of calcium carbonate materials such as speleothem or coral. Unlike other commonly used radiometric dating techniques such as rubidium–strontium or uranium–lead dating, the uranium-thorium technique does not measure accumulation of a stable end-member decay product. Instead, it calculates an age from the degree to which secular equilibrium has been restored between the radioactive isotope thorium-230 and its radioactive parent uranium-234 within a sample. Thorium is not