On the occurrence of uranium in ancient conglomerates

In recent discussions on the origin of the mineralization of the Wit-watersrand and of Blind River, various departures from actualistic prin-ciples have been postulated by geologists of the placerist school in necessary support of their views. None of these hypotheses tands up to critical ex-amination; and from consideration of the mineralogy and geochemistry of the banker reefs it is concluded that the mineralization is certainly not of alluvial origin. Claims that detrital uraninite can be recognized in min-eragraphic studies lack due objectivity. Because of reworking of the uranium and the probable presence of old radiogenic lead, it is not yet possible to place any reliance on the apparent ages recorded for these banker ores. In speculation on the source of the pay-metals, it is sug-gested that the mineralization may be linked to periods of granitization late in the history of the Witwatersrand and HuronJan geosynclines. I NTRODUCTIO