Some aspects of volcanic ash layers in the Central Indian Basin

A Comprehensive View of Manganese Nodules and Volcanics of the Central Indian Ocean Basin

“…Some workers (e.g., Pattan et al, 1999) suggested that the shards in the CIOB were transported and deposited after the super-eruption of Toba volcano in northern Sumatra about 74 ka ago (Rose and Chesner, 1987). Sukumaran et al (1999) opposed the view that the shards could have been carried 3000 km from Toba. Those authors favored the view, based on 230 Th xs values and radiolarian biostratigraphy of sediment cores, that the shards might have been derived from sub-oceanic volcanic activities during periods of elevated glaciation.…”

Depositional environment of the surface sediments in Central Indian Basin (CIB), Indian Ocean, between 8°–18°S latitude and 72°–79°E longitude, based on their geochemical characteristics

“…However, early diagenetic enrichment or terrestrial input cannot account for 10-25 times enrichment of Mn (with respect to PAAS value) in the surface sediments of the CIB. The main sources of marine iron and manganese are the underwater volcanoes and hydrothermal vents (Bonatti & Nayudu, 1965;Boström & Peterson, 1966;Krauskopf, 1957;Lynn & Bonatti, 1965;Nishioka, Obata, & Tsumune, 2013), and there are evidences of abundant glass shards and other volcanogenic components in the CIB sediments, which were reported to have been derived from the widespread Toba Tuff explosion and past in situ volcanism in this basin (Pereira, Nath, Borole, & Gupta, 2006;Pereira et al, 2016;Sukumaran, Banerjee, Borole, & Gupta, 1999). These could be also a potential source of both SiO 2excess and Al excess .…”