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The durations of Silurian graptolite zones

Published online by Cambridge University Press:  01 May 2009

Richard A. Hughes
Richard A. Hughes
Affiliation:
British Geological Survey, Murchison House, West Mains Road, Edinburgh EH9 3LA
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Abstract

Recently published radiometric data show the duration of the Silurian Period to be approximately 32 Ma, significantly longer than previous estimates. Radiometric and graphic correlation studies demonstrate considerable variation in the durations of the four Silurian epochs: approximately 13 Ma for the Llandovery, 4 Ma for the Wenlock, 5 Ma for the Ludlow and 10 Ma for the Přídolí. Using this new geochronological data, figures for average graptolite zone duration are presented for each epoch, ranging from as little as 0.44 Ma in the Wenlock, to 1.43 Ma in the Přídolí. The figures provide a refined subdivision of the Silurian timescale, of value to studies which use Silurian graptolite zones to calibrate geological processes.

Type
Rapid Communications
Information
Geological Magazine , Volume 132 , Issue 1 , January 1995 , pp. 113 - 115
Copyright
Copyright © Cambridge University Press 1995

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