Deep-sea record of Cenozoic explosive volcanism in the North Atlantic.

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Cenozoic explosive volcanism associated with rifting and continued opening of the Norwegian and Greenland Seas has produced two compositional series of silicic tephra. These are preserved in deep-sea sediments. A high-potash and high-alumina series of glasses range from quartz-trachytes to alkali rhyolites and associated comendites. A low-potash series, ranging from icelandites through dacites and rhyolites, is characterised by low alumina and enriched in Fe and Ca. Both series have been erupted throughout the Cenozoic. The deep-sea cores indicate five apparent episodes of Cenozoic explosive volcanism. The first is a late Paleocene episode recorded in North Sea exploration wells and stems from volcanic activity in the British Isles. A middle Eocene episode is attributed to volcanism on the subaerial Iceland-Faeroes ridge. The middle Oligocene episode coincides with the Kialineq plutonic event in E Greenland. The subsequent lull in rhyolitic explosive volcanism during late Oligocene coincides with minimum activity of the hotspot, low spreading rates and absence of known subaerial volcanic sources. An early to middle Miocene episode is attributed to rejuvenation of the Iceland hotspot and emergence of subaerial Iceland, whereas the Plio-Pleistocene increase in explosive silicic volcanism coincides with rift-jumping between the Icelandic volcanic zones. Ash-fall dispersal in the region is dominated by westerly winds, except during glacial stages, when ice-rafting leads to tephra deposition S of Iceland.-Authors

Publication Title, e.g., Journal

Tephra studies. Proc NATO ASI 'Tephra studies as a tool in Quaternary research', Iceland, 1980