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Ages apparents par la methode plomb-alpha de zircons extraits de roches cristallines dAfrique equatoriale francaise et du Cameroun


, : Ages apparents par la methode plomb-alpha de zircons extraits de roches cristallines dAfrique equatoriale francaise et du Cameroun. Report of the

The results of 14 lead-alpha age determinations on zircons from crystalline rocks of French Equatorial Africa and Cameroun are tabulated and discussed briefly. The results are not yet conclusive. Either there is a great difference in age between the granites of the northern and southern parts of the region, or else the zircon has been modified systematically by climatic factors. The dry climate of the north would favor loss of radon, giving apparent ages lower than the true age, whereas the humid climate of the south would cause lossof uranium and thorium, giving apparent ages that are too high.

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