Premium
Chemical alteration of tephra in the depositional environment: theoretical stability modelling
Author(s) -
Pollard A. M.,
Blockley S. P. E.,
Ward K. R.
Publication year - 2003
Publication title -
journal of quaternary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.142
H-Index - 94
eISSN - 1099-1417
pISSN - 0267-8179
DOI - 10.1002/jqs.760
Subject(s) - tephra , tephrochronology , sedimentary depositional environment , rhyolite , geology , chemical stability , durability , leaching (pedology) , geochemistry , earth science , chemistry , materials science , paleontology , volcano , soil science , composite material , organic chemistry , soil water , structural basin , volcanic rock
The study of the chemical stability of vitreous material in aqueous media is well‐established. There has to date been little consideration of the implications of variations in the chemical durability of tephra in Quaternary tephrochronology. Chemical alteration can take the form of cationic leaching from the matrix, or complete destruction of the silica network, either of which could constrain the ability to chemically identify distal tephra. Here we apply established models of vitreous durability to the published chemical analyses of a large number of Icelandic tephras in order to predict their relative durabilities under equivalent conditions. This suggests that some important tephras have relatively poor chemical stability, and that rhyolitic tephras are, in general, more stable than basaltic. We conclude that tephras should be expected to show predictable differential chemical stability in the post‐depositional environment. Copyright © 2003 John Wiley & Sons, Ltd.