Were rhyolitic glasses in the Vedde Ash and in the North Atlantic's Ash Zone 1 produced by the same volcanic eruption?

Publication Type  Journal Article
Year of Publication  2001
Authors  Bond, G. C.; Mandeville, C.; Hoffmann, S.
Journal Title  Quaternary Science Reviews
Volume  20
Issue  11
Pages  1189-1199
Journal Date  May
ISBN Number  0277-3791
Accession Number  ISI:000169260200003
Key Words  grip ice core; greenland ice; last deglaciation; late quaternary; western norway; iceland; sediments; sea; holocene; record

New evidence from North Atlantic deep-sea sediment cores suggests that rhyolitic glass shards in Ash Zone 1 and in the Vedde Ash may not have been produced by the same eruption as has been widely assumed. Our argument is based on (1) a marine ice-rafted deposit approximately 1000 years older than the Vedde Ash contains rhyolitic shards with the same major element chemistry as the Vedde Ash itself and (2) coincidence of Ash Zone 1 with an abrupt increase in discharge of glacial icebergs into the North Atlantic. Hence, we cannot rule out the possibility that Vedde-like rhyolitic glasses were erupted onto Icelandic glaciers before eruption of the Vedde Ash, stored in the glacial ice, then dispersed by icebergs into the North Atlantic and deposited partly or entirely as Ash Zone 1. While not disproving that Ash Zone 1 and the Vedde Ash came from the same eruption, our findings indicate that further study is needed to establish the exact relation between the two ash deposits. (C) 2001 Elsevier Science Ltd. All rights reserved.


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