The tephrochronology of Iceland and the North Atlantic region during the Middle and Late Quaternary: a review

The tephrochronology of Iceland and the North Atlantic region is reviewed i n order to construct a unified framework for the last 400 kyr BP. Nearly al l of the tephra layers described are also characterised geochemically. A nu mber of new tephra layers are analysed for the first time for their geochem ical signature and a number of pre-Holocene tephra layers have been given a n informal denotation. The tephrostratigraphy of Ash Zone II is highlighted . Where possible the rhyolitic tephra layers found outside Iceland have bee n correlated to known Icelandic tephra layers or to the volcanic source are a. The application of tephra fallout in various depositional environments i s described and discussed. Copyright (C) 2000 John Wiley & Sons, Ltd.