Anyuiskii

Two stages of extrusive activity have been identified at this locality. The first stage is characterised by extensive lava flows of basalt, which ran along the valley of the Monka River; they have been traced over a region 53 km long by 2-4 km wide, cover an area of about 100 km2 and have a total volume of 3 km3. The lavas were erupted from numerous fissures and consist of mildly alkaline basalts. The second stage of activity began with the explosive eruption of basaltic andesites which were then followed by further mildly alkaline trachybasalts, with normative nepheline, which form volcanoes and isolated lava flows. The most extensive lava flow in this final phase of eruption is about 12 km long, 1.5-2.2 km wide and has a thickness of 10-20 m. The total area of lava flows of the second stage is 124 km2.