Use of magnetic signatures to correlate tephra layers in Holocene loessial soil profiles from a small region, SE Iceland

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• 作者：Dunsheng Xia ; Xi Chun ; Jan Bloemendal ; Richard C. Chiverrell and Fahu Chen
• 关键词：Environmental magnetism ; Tephra ; Principal coordinates analysis ; Iceland
• 刊名：Environmental Geology
• 出版年：2007
• 出版时间：February, 2007
• 年：2007
• 卷：51
• 期：8
• 页码：1425-1437
• 全文大小：572 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geology
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-0495

文摘

Rock magnetic measurements have been applied to two adjacent loessial soil sections from a small region, SE Iceland. The soils are composed of reworked locally derived sediment (including airfall tephra) and also contain several visible discrete airfall tephra layers. The main magnetic minerals in the airfall tephras are ferrimagnetic (e.g. magnetite) with paramagnetic minerals also present. The main magnetic grain sizes in the tephras are pseudo single domain. The results show that individual tephras do not have unique magnetic signatures that can be used for identification and correlation between sedimentary sequences. However, a correlation of tephra layers was achieved through the application of statistical techniques to a comprehensive dataset of magnetic parameters. Similarity coefficients and Euclidian distance measures were used to identify the best correlation between tephra layers in the two soil profiles. The technique works well providing some tephras present within both profiles have been formally identified (e.g. Oraefajokulla ad 1362) using electron microprobe analyses. Given this initial framework, the statistical analyses of the magnetic parameters can help in the identification and correlation of unknown tephras between two soil profiles.