Significant uranium deposits are distributed in a complex pattern throughout the eastern and southern, the central, and the northern Rocky Mountains; and the Black Hills uplift, Dakota plains, and Wyoming basins. Consideration of uranium deposits in the Colorado Plateau is not included in this paper.

In considering the wide variety of known types of uranium deposits, under any scheme of classification, it is noted that nearly all types occur in the Rocky Mountain region. It seems likely that there is also considerable variety in the genetic history of uranium emplacement in the various types. However, tectonic influence appears to be consistently important throughout the entire pattern of distribution.

The relation of ore deposition to regional structural features is illustrated by the concentration of uranium minerals: (1) along or near major tensional faults; (2) along or near major lineaments; (3) at the flanks of structural basins, and (4) on structural terraces.

The striking influence of the broad tectonic framework of the earth's crust on world-wide uranium distribution patterns supports the conclusion that the Rocky Mountains region is but one segment of one of the world's great uranium "provinces." The variety of ore types within this area is the result of complex redistribution processes following the introduction of uranium into the upper parts of the earth's crust by juvenile solutions along controlling structure. Sedimentation, ground-water movement, and the transfer of organic material, all influenced in turn by tectonic history, have had an important bearing on uranium concentration in many parts of the large area discussed.

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