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Dating the transition of smectite to illite in Palaeozoic mudrocks using the Rb-Sr whole-rock technique

J. A. Evans
Dating the transition of smectite to illite in Palaeozoic mudrocks using the Rb-Sr whole-rock technique
Journal of the Geological Society of London (January 1996) 153, Part 1: 101-108

Abstract

Two new Rb-Sr whole-rock regressions are presented for stratigraphically well-constrained samples from the Ordovician and Silurian of central Wales, together with K-Ar and Rb-Sr data from the <<<$I> 2 mu m illite fraction of samples from these and published whole-rock suites. Eight K-Ar ages from the <<<$I> 2 mu m fractions gave ages which show a normal distribution and indicate a Devonian age of 399 + or - 3 m.y. Rb-Sr whole-rock ages are less consistent, giving 431 + or - 10, 428 + or - 14, 414 + or - 6 and 403 + or - 15 m.y.; Rb-Sr data from the illite fractions do not generate a linear array. The Rb-Sr whole-rock isochron ages are interpreted as dating the time of passage of the rock through the smectite-illite transition, because the radiometric ages correspond well with the estimated time of this reaction.


ISSN: 0016-7649
EISSN: 2041-479X
Coden: JGSLAS
Serial Title: Journal of the Geological Society of London
Serial Volume: 153, Part 1
Title: Dating the transition of smectite to illite in Palaeozoic mudrocks using the Rb-Sr whole-rock technique
Author(s): Evans, J. A.
Affiliation: NERC Isotope Geosciences Laboratory, Nottingham, United Kingdom
Pages: 101-108
Published: 199601
Text Language: English
Publisher: Geological Society of London, London, United Kingdom
References: 34
Accession Number: 1996-050146
Categories: GeochronologySedimentary petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 6 tables, geol. sketch map
N50°00'00" - N52°30'00", W04°15'00" - W03°30'00"
Country of Publication: United Kingdom
Secondary Affiliation: GeoRef, Copyright 2018, American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Update Code: 199617
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