NEW DATA ON BASALT VOLCANISM IN THE MALAYA BOTUOBUYA DISTRICT WESTERN YAKUTIA

Abstract

There is little information about pre-Late Paleozoic volcanism in Siberia because the corresponding volcanic systems were largely eroded during the Mesozoic. However, by studying the few volcanic bodies now known and penetrated chiefly in drilling, it should be possible to identify, among the Devonian volcanic structures of the Malaya Botuobuya district, two compositionally different types of explosion pipes. The first includes the Chuonaryl pipe described above. It is filled by xenotuffs whose fragments consist of Lower Paleozoic carbonate rocks and, to a lesser extent, of mafic volcanic glass and Middle Devonian intrusive dolerite and gabbro-dolerite. The analogs of such xenotuffs among younger volcanic rocks are still unknown.