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Brian Turner: Adventures of an Exploration Geologist - Gold & Uranium

Because of global warming and the fact that nuclear power does not produce climate warming gases, the price of uranium has suddenly increased as various governments, including the UK government, plan to build more nuclear power plants. Uranium is present in Permian-Triassic sandstones in the Karoo Basin, South Africa. Exploration reveals that the uranium was leached from granitic-volcanic source material and taken into solution in groundwater under lkaline/oxidising conditions.

The mineralised groundwater preferentially moved through channel sand bodies and, on encountering a reducing agent, was precipitated from solution as primary uranium minerals. Proterozoic gold deposits in Guyana, South America are similar to those in the Witwatersrand Basin, South Africa. They occur in quartz arenites which form a prominent escarpment in the almost inaccessible interior of the country. Exploration reveals that gold tends to concentrate in specific parts of the succession associated with auriferous gravels, which modelling suggests represent low stand or transgressive reworking of older deposits, probably derived from the gold-bearing Archean basement. The gold deposits have themselves been subject to erosion and reworking to form recent gold-bearing sands and gravels deposited along the numerous streams and rivers, commonly worked by local prospectors and large dredgers. In his lecture Brian Turner will explore some of these ideas and discuss his involvement with the search for these important resources.