Abstract

K/Ar age determinations on biotite from the carbonated biotite pyroxenite of the Musensi Hill intrusion gave 96 + or - 9 and 101 + or - 12 million years, or middle Cretaceous. The nearby Panda Hill carbonatite, on stratigraphic evidence, is considered pre-Karroo and earlier than the Musensi Hill intrusion. Feldspar from feldspathized carbonate rock of the Mbeya range gives a K/Ar age of 100 + or - 10 m.y., indicating its contemporaneity with the Musensi Hill intrusion and affinity of the dike rocks in the fault zone of the rift valley with the carbonatite suite.

You do not currently have access to this article.