Large explosive volcanic eruptions generate extensive regional tephra deposits that provide favorable conditions for identifying the source of volcanoes, comparing the sedimentary strata of a region and determining th...Large explosive volcanic eruptions generate extensive regional tephra deposits that provide favorable conditions for identifying the source of volcanoes, comparing the sedimentary strata of a region and determining their ages. The tephra layer, referred to as B- Tm, generated by the Millennium eruption of Chang- baishan volcano, is widely distributed in Northeast China, Japan, D.P.R. Korea, and the nearby coastal area of Russia. It forms part of the widespread northeast Asian strata and is significant for establishing an isochronal stratigraphic framework. However, research on the temporal characterization and stratigraphic correlation of associated strata using this tephra layer is mainly concentrated in and near Japan. In northeastern China, this tephra layer is seldom seen and its application in stratigraphic correlations is even rarer. More importantly, the determination of accurate ages for both distal and proximal tephras has been debated, leading to controversy in discussions of its environmental impacts. Stratigraphic records from both distal and proximal Changbaishan ash show that this eruption generally occurred between 1,012 and 1,004 cal yr BP. Geochemical comparison between Changbaishan ash and the Quaternary widespread ash around Japan illustrates that Changbaishan ash is a continuous composition from rhyolitic to trachytic and its ratio of FeOT to CaO is usually greater than 4, which can be used as a distinguishing identifier among worldwide contemporary eruptions.展开更多
After almost 7 years of dormancy,Hunga Tonga-Hunga Haʻapai Volcano(HTHHV)erupted on December 20^(th),2021.HTHHV is located in the South Pacific Ocean,65 km north of Tongatapu,Tonga’s main island.The volcano erupted a...After almost 7 years of dormancy,Hunga Tonga-Hunga Haʻapai Volcano(HTHHV)erupted on December 20^(th),2021.HTHHV is located in the South Pacific Ocean,65 km north of Tongatapu,Tonga’s main island.The volcano erupted again violently on January 15^(th),2022,causing loud booms thatwere heard across the Pacific Ocean,ejecting 30 km-high ash clouds into the stratosphere,and triggering severe tsunamis;ash from the eruption caused communication networks to collapse.展开更多
基金Acknowledgements The authors thank the anonymous reviewers and the editor for their helpful reviews and constructive suggestions which greatly improved the original manuscript. We also thank Drs. Z Guo, H He, X Chen and L Zhang for their help during the preparation of this manuscript. This work was supported by the National Natural Science Foundation of China （Grant Nos. 41272369, 40802038, and 41320104006）.
文摘Large explosive volcanic eruptions generate extensive regional tephra deposits that provide favorable conditions for identifying the source of volcanoes, comparing the sedimentary strata of a region and determining their ages. The tephra layer, referred to as B- Tm, generated by the Millennium eruption of Chang- baishan volcano, is widely distributed in Northeast China, Japan, D.P.R. Korea, and the nearby coastal area of Russia. It forms part of the widespread northeast Asian strata and is significant for establishing an isochronal stratigraphic framework. However, research on the temporal characterization and stratigraphic correlation of associated strata using this tephra layer is mainly concentrated in and near Japan. In northeastern China, this tephra layer is seldom seen and its application in stratigraphic correlations is even rarer. More importantly, the determination of accurate ages for both distal and proximal tephras has been debated, leading to controversy in discussions of its environmental impacts. Stratigraphic records from both distal and proximal Changbaishan ash show that this eruption generally occurred between 1,012 and 1,004 cal yr BP. Geochemical comparison between Changbaishan ash and the Quaternary widespread ash around Japan illustrates that Changbaishan ash is a continuous composition from rhyolitic to trachytic and its ratio of FeOT to CaO is usually greater than 4, which can be used as a distinguishing identifier among worldwide contemporary eruptions.
文摘After almost 7 years of dormancy,Hunga Tonga-Hunga Haʻapai Volcano(HTHHV)erupted on December 20^(th),2021.HTHHV is located in the South Pacific Ocean,65 km north of Tongatapu,Tonga’s main island.The volcano erupted again violently on January 15^(th),2022,causing loud booms thatwere heard across the Pacific Ocean,ejecting 30 km-high ash clouds into the stratosphere,and triggering severe tsunamis;ash from the eruption caused communication networks to collapse.
