Jom-Bolok volcanic field

Jom-Bolok, also known as Volcano Valley and East Sayan Volcanic Field, is a volcanic field in Russia, 200 kilometres (120 mi) west of Lake Baikal. It is part of the Baikal rift zone which is also responsible for volcanism elsewhere around Lake Baikal. The volcanic activity has generated long lava flows and cinder cones. One of the lava flows is 70 kilometres (43 mi) long and has a volume of 7.9 cubic kilometres (1.9 cu mi).

Volcanic activity in the field commenced during the late Pleistocene in an area that had been previously influenced by glaciers and with even earlier volcanic and tectonic activity. Magma probably formed during deglaciation was erupted during the early Holocene, generating the long lava flow. A much more recent eruption in the southern part of the field may be referenced in Mongolian chronicles.