Rapid development of the great Millennium eruption of Changbaishan (Tianchi) Volcano, China/North Korea: Evidence from U-Th zircon dating

摘要

The Changbaishan (Tianchi) volcano extending across the border of northeast China and North Korea erupted-100 km~3 peralkaline rhyolites around 1000 AD. This Millennium eruption of the Changbaishan volcano is one of the two largest explosive eruptions in the past 2000 years. Here we report the results of uranium-thorium dating of zircons from the Changbaishan volcanic rocks. Our data indicate that the rhyolitic magmas were stored in the crust for only 8.2 ± 1.2 ka prior to eruption. Based on titanium-in-zircon geothermometer and alkali feldspar-glass geothermometer, the rhyolitic magmas were formed at a relatively low temperature (~740±40°C). This storage time is very short compared with other large volume catastrophic silicic eruptions. This work demonstrates that peralkaline rhyolitic magmas from the Changbaishan volcano can develop into a catastrophic eruptive phase quite quickly.