Growth and thermal maturation of the Toba magma reservoir

The Toba volcanic system in Indonesia has produced two of the largest eruptions (>2,000 km³ dense-rock equivalent [DRE] each) on Earth since the Quaternary. U–Pb crystallization ages of zircon span a period of ∼600 ky before each eruptive event, and in the run-up to each eruption, the mean and va...

Full description

Saved in:
Bibliographic Details
Published inProceedings of the National Academy of Sciences - PNAS Vol. 118; no. 45; pp. 1 - 9
Main Authors Liu, Ping-Ping, Caricchi, Luca, Chung, Sun-Lin, Li, Xian-Hua, Li, Qiu-Li, Zhou, Mei-Fu, Lai, Yu-Ming, Ghani, Azman A., Sihotang, Theodora, Sheldrake, Tom E., Simpson, Guy
Format Journal Article
LanguageEnglish
Published United States National Academy of Sciences 09.11.2021
Subjects
Online AccessGet full text

Cover

Loading…
More Information
Summary:The Toba volcanic system in Indonesia has produced two of the largest eruptions (>2,000 km³ dense-rock equivalent [DRE] each) on Earth since the Quaternary. U–Pb crystallization ages of zircon span a period of ∼600 ky before each eruptive event, and in the run-up to each eruption, the mean and variance of the zircons’ U content decrease. To quantify the process of accumulation of eruptible magma underneath the Toba caldera, we integrated these observations with thermal and geochemical modeling. We show that caldera-forming eruptions at Toba are the result of progressive thermal maturation of the upper crustal magma reservoir, which grows and chemically homogenizes, by sustained magma influx at average volumetric rates between 0.008 and 0.01 km³/y over the past 2.2 My. Protracted thermal pulses related to magma-recharge events prime the system for eruption without necessarily requiring an increased magma-recharge rate before the two supereruptions. If the rate of magma input was maintained since the last supereruption of Toba at 75 ka, eruptible magma is currently accumulating at a minimum rate of ∼4.2 km³ per millennium, and the current estimate of the total volume of potentially eruptible magma available today is a minimum of ∼315 km³. Our approach to evaluate magma flux and the rate of eruptible magma accumulation is applicable to other volcanic systems capable of producing supereruptions and thereby could help in assessing the potential of active volcanic systems to feed supereruptions.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
Edited by Katharine V. Cashman, University of Bristol, Bristol, United Kingdom, and approved September 29, 2021 (received for review January 27, 2021)
Author contributions: P.-P.L. and S.-L.C. designed research; P.-P.L., Y.-M.L., A.A.G., and T.E.S. performed research; L.C., X.-H.L., Q.-L.L., T.S., and G.S. contributed new reagents/analytic tools; P.-P.L. analyzed data; and P.-P.L., L.C., M.-F.Z., and T.E.S. wrote the paper.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.2101695118