YUKON EXPLORATION AND GEOLOGY 2003 191 Distal micro-tephra deposits in southeast Alaskan peatlands
Volcanic ash (tephra) provides a valuable tool in palaeoenvironmental research. Traditionally, the main emphasis in tephra studies has been on layers which are visible to the naked eye. Recently a large body of work in Europe has been established investigating microscopic tephra layers. Microscopic...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.519.8765 http://publications.gc.ca/collections/Collection/R71-41-2003E(15).pdf |
| Summary: | Volcanic ash (tephra) provides a valuable tool in palaeoenvironmental research. Traditionally, the main emphasis in tephra studies has been on layers which are visible to the naked eye. Recently a large body of work in Europe has been established investigating microscopic tephra layers. Microscopic methods have allowed a massive expansion of the known limits of tephra deposition; however, they have rarely been used elsewhere in the world. This report summarizes the first use of these methods in northwestern North America. Five peatland sites in southeastern Alaska were cored and analysed for tephra. A total of 14 significant layers were recovered, representing a minimum of 4 different tephras. While it is not yet possible to identify the source of these layers, these results are significant as they show that microscopic methods may prove a valuable tool enabling an expanded tephrochronology and a better understanding of volcanic impacts in the region. RÉSUMÉ Les cendres volcaniques (téphra) constituent un outil très utile pour la recherche paléo-environnementale. Jusqu’à ce jour, les études portant sur le téphra étaient surtout axées sur les |
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