Age and Volcanic History of the Dariganga Volcanic Field (SE Mongolia)

The results of systematic K–Ar geochronological studies are presented for the rocks of the Late Cenozoic basaltic Dariganga Volcanic Field (DVF). Four stages of its volcanic history have been identified: Middle-Late Miocene (>10 Ma), Late Miocene-Early Pliocene (7.8–3.5 Ma), Late Pliocene (2.8–2.6 Ma) and Pleistocene (<1.7 Ma). The volcanic products of each stage were suitably distributed over the area of the volcanic field. The main volume of volcanics was erupted during the Late Miocene–Early Pliocene and the Pleistocene. During the Late Miocene–Early Pliocene, the northwestern part of the lava field was formed, which has a lava plateau morphology. Eruption centres were located within structural depressions that developed during extension and accompanied volcanism. The south-eastern part of the DVF was formed during the Pleistocene. Volcanism occurred simultaneously with the uplift of the Khukhot-Ein-Nuruu ridge within the Nukut-Daban highland, which influenced the morphology of the volcanic cover. This volcanic stage is characterised by large multi-centre shield volcanoes localised in the axial zone of the ridge, and extensive valley lava flows spreading down both slopes of the ridge. The volcanic history of the DVF and other volcanic areas of the Late Cenozoic intraplate volcanic province of Central and East Asia are compared. They developed in concert with each other, so the formation of the DVF being initiated by the same geodynamic mechanisms as the other volcanic areas of the province, namely the activity of a small mantle plume.