Abstract

It is the author's belief that radioactive dating, following the increased accuracy and extent of determinations, is an important complement to structural mapping not only in the elucidation of Precambrian structure and history but also in the study of the distribution of certain mineral deposits. Proterozoic Fe formation and uraniferous conglomerates have been noted as examples of such deposits that appear to have a direct relationship to Archean-Proterozoic boundaries. Various other deposits, particularly of base metals, appear to have a spatial, but less direct relationship to such boundaries. By reason of unusually good rock exposures, relatively little disturbance since Precambrian times, and a rather concentrated study over the past few years, the Keewatin nucleus of North America and its adjoining tectonic provinces may be the best model to use in the study of similar, but perhaps more complex, Precambrian areas in other parts of the world. The examples quoted give some indication that similar relationships between economic deposits and Archean-Proterozoic boundaries occur on other continents. Large areas of Precambrian in Africa, India, and South America, the geological details often clouded by tropical weathering and vegetation, await a comprehensive study to correlate the isolated parts that have already been mapped in some detail. In Africa such areas of Precambrian extend over the political boundaries of newly independent nations, which are anxious to develop their natural resources as quickly and efficiently as possible. One of the more useful contributions that could be made by geologists familiar with the Precambrian of the North American continent would be the application to such parts of Africa, and other continents, of the emerging knowledge and patterns of certain ore deposits associated with the boundaries of the Keewatin nucleus. This knowledge and experience should be applied on a continental rather than a national scale and should be coordinated with an extensive use of age determinations. The medium for such cooperation might, at least in the earlier stages, be one of the technical aid programs under the United Nations Organization.

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