The 1928?1929 eruption of Kammourta volcano ? evidence of tectono-magmatic activity in the Manda-Inakir rift and comparison with the Asal Rift, Afar depression, Republic of Djibuti

Abstract

There are two rifts zones in the Republic of Djibuti: the active Asal rift (birthplace of the Ardoukoba basaltic volcano in 1978) and the poorly known Manda-Inakir rift described here. The most recent volcanic event in the Manda-Inakir rift was the formation of the Kammourta basaltic cone, probably in 1928, accompanied by strong seismic activity. This historic eruption and related tectonic features show that the Manda-Inakir rift, like Asal, is presently active. The Kammourta basalt, of transitional alkaline type, belongs to the Manda-Inakir differentiated series, which ranges from basalt to rhyolite. In contrast, volcanic rocks of the Asal rift are entirely transitional tholeiitic basalt. The differences in magmatic affinity and tectonics between these two rift zones reflect the more advanced evolution of rifting in the Asal zone than in Manda-Inakir.