Volcanism and extension between the Main Ethiopian and Gregory rifts

The objectives of geological, remote sensing, geochronological, and gravity studies in the broad zone of overlap between the Kenya and Main Ethiopian rifts were to establish a chronology of rifting and volcanism, to correlate volcano-sedimentary strata with those in the northern Kenya and Main Ethiopian rifts, and to map regional variations in the distribution of volcanism and extension during the past 50 Ma. Eighteen new radiometric dates and field observations show 1) a widespread episode of flood basaltic volcanism at 45–35 Ma, with later episodes at 34–28 Ma and 18–12 Ma affecting smaller regions; 2) faulting and felsic volcanism at ∼ 14 Ma concomitant with basin subsidence and sedimentation; 3) volcanism and faulting at ∼ 3 Ma within N-S trending basins.