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Using geochemistry as a tool for correlating proximal andesitic tephra: Case studies from Mt Rainier (USA) and Mt Ruapehu (New Zealand)

Journal of Quaternary Science

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, , ,
DOI: 10.1002/jqs.1065

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Abstract

Volcanic hazards assessments at andesite stratovolcanoes rely on the assessment of frequency and magnitude of past events. The identification and correlation of proximal and distal andesitic tephra, which record the explosive eruptive history, are integral to such assessments. These tephra are potentially valuable stratigraphic marker beds useful to the temporal correlation and age dating of Quaternary volcanic, volcaniclastic and epiclastic sedimentary deposits with which they are interbedded. At Mt Ruapehu (New Zealand) and Mt Rainier (USA), much of the detail of the recent volcanic record remains unresolved because of the difficulty in identifying proximal tephra. This study investigates the value of geochemical methods in discriminating andesitic tephra. Our dataset comprises petrological and geochemical analyses of tephra that span the late Quaternary eruptive record of each volcano. Our data illustrate that andesitic tephra are remarkably heterogeneous in composition. Tephra compositions fluctuate widely over short time intervals, and there are no simple or systematic temporal trends in geochemistry within either eruptive record. This complexity in tephra geochemistry limits the application of geochemical approaches to tephrostratigraphic studies, beyond a general characterisation useful to provenance assignation. Petrological and geochemical data suggest that the products of andesite systems are inherently variable and therefore intractable to discrimination by simple geochemical methods alone. Copyright ?? 2006 John Wiley & Sons, Ltd.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Using geochemistry as a tool for correlating proximal andesitic tephra: Case studies from Mt Rainier (USA) and Mt Ruapehu (New Zealand)
Series title:
Journal of Quaternary Science
DOI:
10.1002/jqs.1065
Volume
22
Issue:
4
Year Published:
2007
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of Quaternary Science
First page:
395
Last page:
410
Number of Pages:
16