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(Article of periodic en Anglais - 1982)

Document title

Mineralogy and phase chemistry of Mount St. Helens tephra sets W and Y as keys to their identification

Authors(s) and Affiliation(s)

SMITH D. R. ; LEEMAN W. P. ;

Abstract

Voluminous and widespread tephras were produced frequently during the last 36,000 yr of volcanic activity at Mount St. Helens. Numerous tephra sets have been defined by D. R. Mullineaux, J. H. Hyde, and M. Rubin (1975, U. S. Geological Survey Journal of Research, 3, 329-335) on the basis of field relations, Fe-Mg phenocryst assemblage, and C chronology and are valuable marker beds for regional stratigraphic studies. In this study modal abundances and mineral compositions were determined (via petrographic and electron microprobe techniques) for numerous samples of individual layers within tephra sets W and Y to evaluate the degree of compositional variability within and between tephra layers and criteria by which to distinguish among Mount St. Helens and other Pacific Northwest tephras.

Source

Article of periodic

published at : Quaternary research New York

Editor :

Millesime : 1982, vol. 17, no2 [pp. 211-227]

Bibliographic references : 29 réf.

Language

Anglais

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