The VEI-7 Millennium eruption, Changbaishan-Tianchi volcano, China/DPRK: New field, petrological, and chemical constraints on stratigraphy, volcanology, and magma dynamics

Recently published geochronological data integrated with our new petrochemical and volcanological framework informs the magma dynamics leading to the ME. The ME comendite, derived from a parental trachyte similar to the BGM started accumulating at shallow levels around 12 ka to 8 ka. Around 4 to 1.6 ka the BGM trachyte sensu strictu separated from its basaltic parent and started accumulating and crystallizing separately from the ME comendite. Just prior to the ME eruption, mingling of trace amounts of a third more mafic hybrid is implicated by the composition of mafic glass selvedges. The strong evidence for mixing of all these endmembers in the eruption products suggests that recharge mixing and overturn of this predominantly comendite-trachyte system occurred during the ~ 1 ka ME. The common occurrence of comendite and trachyte in the last 100 ka (also maybe 1 Ma) at Changbaishan-Tianchi suggests that conditions for trachyte-comendite magma interactions are prevalent in the magma system of Changbaishan and maybe crucial in catastrophic eruptions there.