Geology and recognition criteria for uranium deposits of the quartz-pebble conglomerate type. Final report

Abstract

The distribution of uranium reserves in various deposit types through geologic time (after D.S Robertson and others, 1978). 2. The economic and subeconomic occurrences of Precambrian uraniferous conglomerates of the world.

Understanding Mineral Deposits

“…Moreover, 0 18 0 values of chert pebbles from both Huronian and Witwatersrand conglomerates (9 to 11.5%0) are much lower than those expected for Archean and Proterozoic marine cherts (commonly > 16%0; Knauth & Epstein 1976) and effectively exclude auriferous iron-formations and exhalites as likely sources of gold in these deposits (Vennemann et al 1992). The proposal lacks direct proof, but is supported by mass balance calculations, the observation that the highest grade placers mostly overlie low-angle unconformities, and the interpretation of Button and Adams (1981) that the unconformities and overlying placers are product of degradation related to a lowering of the base level of erosion. Detrital quartz particles from the Basal Reef contain two generations of fluid inclusions -one set comprising moderately saline (7-16 wt% NaCI equivalent), predominantly NaCI solutions with homogenization temperatures of 200° to 220°C; and the other set comprising low-salinity «5 wt% NaCI equivalent), NaCI-bearing aqueous inclusions with homogenization temperatures of 160° to 190°C.…”

Terrigenous Clastic Depositional Systems

“…The geology of quartz-pebble conglomerate ores has been reviewed in detail by Button and Adams (1981), who interpreted their genesis as a part of a distinct, time-bounded metallogenic epoch. Together these account for approximately 20% of world uranium reserves.…”

“…Basaltic flows and interbedded volcaniclastics As emphasized by Button and Adams (1981), the succession is laced with unconformities which exerted considerable influence on both depositional and mineralization patterns. A quartzarenite assemblage of medium to coarse, texturally and mineralogically mature sand with sericite matrix 2.…”