Proterozoic biotite Rb–Sr dates in the northwestern part of the Yilgarn Craton, Western Australia

Autor: J.R. De Laeter, R. A. Armstrong, W. G. Libby
Rok vydání: 1999
Předmět:
Zdroj: Australian Journal of Earth Sciences. 46:851-860
ISSN: 1440-0952
0812-0099
Popis: Rb–Sr dating of biotite in the northwestern corner of the Yilgarn Craton identified four areas with distinctive age ranges. Biotite in the northwestern area, which includes the Narryer Terrane and part of the Murchison Terrane, yields reset Rb–Sr dates of ca 1650 Ma. In the western area, along the margin of the craton, biotite has been reset to 629 Ma. Eastward of these areas, mainly in the Murchison Terrane, the modal biotite date is near 2450 Ma, though because of a skewed distribution the mean date is closer to 2300 Ma. Dates in a transition zone between the western and eastern areas range broadly between 2000 and 1000 Ma, averaging about 1775 Ma. The western area and the transition zone are continuous with analogous areas south of the limits of the present study. The 1650 Ma dates in the northwestern area are probably related to plutonic and tectonic activity of similar age in the Gascoyne Province to the north. They may represent cooling after thermal resetting during tectonic loading by southward th...
Databáze: OpenAIRE
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