Correlation of the oldest Toba Tuff to sediments in the central Indian Ocean Basin

Journal of Earth system science

E V S S K Babu2¹  J N Pattan1²  M Shyam Prasad1² 

[1] National Geophysical Research Institute (CSIR), Uppal Road, Hyderabad 500 007, India.$$;National Institute of Oceanography (CSIR), Dona Paula, Goa 403 004, India.$$

关键词: Central Indian Ocean Basin;    ash layer;    Australasian microtektite;    layer D;    oldest Toba Tuff;    new volume estimates.;   

DOI  :  

学科分类：天文学(综合)

来源: Indian Academy of Sciences

【 摘 要 】

We have identified an ash layer in association with Australasian microtektites of ∼0.77Ma old in two sediment cores which are ∼450 km apart in the central Indian Ocean Basin (CIOB). Morphology and chemical composition of glass shards and associated microtektites have been used to trace their provenance. In ODP site 758 from Ninetyeast Ridge, ash layer-D (13 cm thick, 0.73–0.75 Ma) and layer-E (5 cm thick, 0.77–0.78 Ma) were previously correlated to the oldest Toba Tuff (OTT) eruptions of the Toba caldera, Sumatra. In this investigation, we found tephra ∼3100 km to the southwest of Toba caldera that is chemically identical to layer D of ODP site 758 and ash in the South China Sea correlated to the OTT. Layer E is not present in the CIOB or other ocean basins. The occurrence of tephra correlating to layer D suggests a widespread distribution of OTT tephra (∼3.6 × 107 km2), an ash volume of at least ∼1800 km3, a total OTT volume of 2300 km3, and classification of the OTT eruption as a super-eruption.

【 授权许可】

Unknown