Most massive volcanic eruptions on Earth are caused either by mantle plumes, deep-seated cylindrical upwellings originating deep in Earth’s mantle, or are part of the volcanic “ring of fire” above subduction zones where oceanic plates are recycled back into the mantle. But some volcanism on continents doesn’t neatly fit into this scheme, including the widespread largely extinct volcanoes found in eastern Australia and Zealandia, which appear to be only indirectly linked to subduction. The magma which fed these volcanoes seems to have its origin in the mantle transition zone at depths of about 400 to 500 kilometres, as suggested in a recent paper by EarthByter Ben Mather and co-authors. But Australia and Zealandia aren’t the only places where such enigmatic volcanism occurs. A quick glance at the AuScope-supported GPlates Portal lithology globe shows that large swathes of eastern Eurasia are littered with intraplate volcanic and plutonic rocks.
This is a companion discussion topic for the original entry at https://www.geo-down-under.org.au/unravellign-the-cause-geodynamic-models-shine-a-light-on-enigmatic-volcanism-in-eastern-asia/