First Toba supereruption revival

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doi: 10.1130/G19903.1
Author(s): Lee, Meng-Yang; Chen, Chang-Hwa; Wei, Kuo-Yen; Iizuka, Yoshiyuki; Carey, Steven
Author Affiliation(s): Primary:
Academia Sinica, Institute of Earth Sciences, Taipei, Taiwan
Other:
National Taiwan University, Taiwan
University of Rhode Island, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 32(1), p.61-64. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2004009. 31 refs.; illus., incl. sketch map
Summary: Little has been known about the earliest Toba eruptive episodes that created the largest-known caldera complex of Quaternary age. Here we report evidence for the eastward dispersal of the oldest Toba tuff in South China Sea sediments to 2500 km away from the source. The tephra deposits occur below the Brunhes-Matuyama geomagnetic boundary (778 ka) and slightly above the Australasian microtektite layer (793 ka). Calibrated by astronomically tuned oxygen isotope stratigraphy, the middle Pleistocene Toba eruption occurred during the deglaciation at 788±2.2 ka, according to the tephra occurrence between marine isotope stages 20 and 19. This refined age is in good agreement with the 40Ar/39Ar date of 800±20 ka for the Toba tephra (layer D) from Ocean Drilling Program (ODP) Site 758, but significantly younger than the commonly cited Ar/Ar age of 840±30 ka. The eruption expelled at least 800-1000 km3 dense-rock-equivalent of rhyolitic magma on the basis of the widespread tephra-fall deposit in the basins of the Indian Ocean and the South China Sea. In spite of its exceptional magnitude, the timing of this major eruption does not indicate a causal linkage between this event and a long-term global climatic deterioration.
Year of Publication: 2004
Research Program: ODP Ocean Drilling Program
Key Words: 24 Surficial Geology, Quaternary Geology; Absolute age; Ar/Ar; Ash falls; Asia; Brunhes Chron; Calibration; Cenozoic; Climate change; Dates; Electron probe data; Eruptions; Experimental studies; Explosive eruptions; Far East; Indonesia; Leg 121; Leg 184; Magmas; Major elements; Marine sediments; Matuyama Chron; Microtektites; North Pacific; Northwest Pacific; ODP Site 1143; ODP Site 758; Ocean Drilling Program; Pacific Ocean; Paleomagnetism; Quaternary; Sediments; South China Sea; Sumatra; Tektites; Tephrochronology; Toba Lake; Upper Cenozoic; Upper Quaternary; Volcanic ash; Volcaniclastics; Volcanoes; West Pacific
Coordinates: N100000 N120000 E1200000 E1170000
N052302 N052303 E0902141 E0902140
N092143 N092143 E1131707 E1131707
N022000 N025600 E0990900 E0983000
Record ID: 2004014676
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