Sedimentary Uranium Deposits

Sandstone-hosted uranium deposits and shale-hosted uranium deposits are exactly what their names imply, that is, uranium minerals in a sandstone or shale host rock. The uranium minerals are usually disseminated through the sedimentary rock.

The sandstone-hosted types appear to have been formed in a similar manner to the stratiform copper deposits, with circulating fluids carrying uranium through the rock and depositing it when they reach a chemical trap. The uranium deposits of Niger and the southwestern United States are sandstone-hosted.

Uranium in these sorts of settings may have occurred through erosion and chemical removal of traces of uranium from other rocks and concentration in the basin where the shales were formed.

Each of the sediment-hosted deposits described above – carbonate lead-zinc, red-bed copper and uranium, can be deformed by later folding and faulting. However, because they form in stable sedimentary basins where there is usually less tectonic activity, they remain un-deformed more often than the exhalative types.