Publication Date:
2016-06-30
Description:
Accurately dating Holocene volcanic rocks poses many challenges but is critical to assessing magmatic evolution and hazard risks at highly active volcanoes. Here we use Ra/Th and 40 Ar/ 39 Ar geochronology to date very young eruptions at Changbaishan volcano, northeastern China, a recently active stratovolcano responsible for one of the most voluminous eruptions in the past ~2000 yr. For Holocene eruptions, 40 Ar/ 39 Ar ages are consistently older than those of both independently determined ages and maximum Ra/Th ages. Overall, Ra/Th ages are most consistent with historical accounts and indicate inaccurate 40 Ar/ 39 Ar ages that are due to extraneous argon in various forms. Ra/Th geochronology also confirms the highly active nature of Changbaishan and supports the continued presence of trachytic magma residing under the volcano that appeared more than ~1100 yr ago.
Print ISSN:
0091-7613
Electronic ISSN:
1943-2682
Topics:
Geosciences
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