Dati geologico—petrografici e radiometrici sulle formazioni affioranti nei dintorni di Djanet (Sahara Centrale)
The outcrops examined are to be found near the oasis of Djanet in Eastern Hoggar (Algerian Sahara). The field observations coupled with petrochemical and radiometric data have led to the recognition of a patch of an Early Ordovician rhyolitic flow (478 m.y.) overlying the granite. This is responsible for the thermo-metamorphism of the rocks of the Pharusian series into which it intruded 90-40 m.y. before the effusion. Thus the denudation of the granitic massif and the formation of the Saharian plateau...