Search results for "Birimian"

Isotopic constraints on the age and formation of a Palaeoproterozoic volcanic arc complex in the Kedougou Inlier, eastern Senegal, West Africa

1997

Abstract The Palaeoproterozoic Kedougou basement in the Mako area in eastern Senegal consists of four major rock complexes: 1) high-grade amphibolitic and gneissic rocks occuring as large xenoliths (the Sandikounda amphibolite-gneiss complex); 2) voluminous bimodal volcanic rocks (the Mako volcanic-plutonic complex); 3) the Sandikounda layered plutonic complex; and 4) trondhjemitic to calc-alkaline intrusive granitoids (the Laminia-Kaourou plutonic complex). Zircons from xenoliths of the Sandikounda amphibolite-gneiss complex yielded ages of ∼2200 Ma, which are slightly older than those of the Mako Supergroup volcanic rocks. These xenoliths also have ɛNd(t) values ranging from +2.4 to +4.1.…