Publication Date:
2024-02-14
Description:
The Toba Caldera on Sumatra, Indonesia is the host of the Young Toba eruption (~74 ka), globally one of the largest and most recognized eruptions during the Quaternary and regionally concentrated in the eastern Indian Ocean. Three older deposits (Middle, and Old Toba Tuff as well as Haranggaol Dacite Tuff) are also attributed to Toba caldera, with their eruption products distributed over the Indian Ocean.
We present the Quaternary marine tephra record from an array of 14 sites and 28 holes from deep ocean drilling programs, complementing earlier work on distal to ultra-distal Indian Ocean sediment cores and terrestrial distribution data of Toba deposits. A unique set of major and trace element glass-shard compositions on 115 primary ash layers together with glass shard morphologies, core pictures and statistical analysis support geochemical fingerprinting between marine tephra layers and known deposits from Toba and five so far unidentified medium to large eruptions assigned to northern Sumatra. Additionally, zircon crystallization ages have been determined for the Haranggaol Dacite Tuff resulting in a new maximum eruption age of 1.42 ± 0.034 Ma.
Tephra volumes and magma masses for the (co-ignimbrite) fallout are estimated based on the compiled marine tephra distribution that are complemented by published proximal ignimbrite volumes. For YTT the resulting tephra and DRE volumes of 5600 km3 and 3600 km3, respectively, are in between the previous estimates. For MTT (253 km3 DRE), ODT (1550 km3 DRE), HDT (129 km3 DRE), and the five additionally identified eruptions from Northern-Sumatran volcanoes, new magma volumes have been determined. Overall, the Indian Ocean tephra record reveals in one large eruption every 200 kyr in the Quaternary that is derived from northern Sumatra.
Type:
Article
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PeerReviewed
,
info:eu-repo/semantics/article
Format:
text
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