Experimental simulation of Colorado Plateau type uranium deposits is di- vided into seven parts. The first three summarize the essential features of geological occurrence for the ores. Details are omitted since they are avail- able in other reports to which reference is made. The last four parts out- line the results of experimental investigation arranged according to each geo- logical group of features influencing mode of occurrence. Both field distri• bution and laboratory approaches to the problem suggest that the origin for . the uranium and for the vanadium are disconnected problems.
The plateau ores occur in or adjacent to fluviatile sediments and generally avoid flood plain and aeolian accumulations. For this reason, a large part of the rocks of the plateau section are not potential host to economic deposits. Even the Shinarump conglomerate fluviatile deposits have the principal pro- duce rs distributed in a pattern which resembles that of the stream placers in seasonally dry regions. The principal deposits occur well down towards the bottom of ~ynclines and are there distributed frequently along a near-contour line; this ore axis may transgress several strata although it stays usually on contour .l,n a stratum. Of the several explanations suggested, onlythe one at- tributing the ore to slight redtstrtbutton by artesian groundwater fails to leave anomalous situations. The structural and physiographic history of the region indicates earliest age for artesian circulation as late Cretaceous and the youngest age as the Canyon Cutting cycle of the late Pliocene. The ores came into their present site during this time interval.

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