RbSr isotope constraints on the timing of late to post-Archa↭ tectonometamorphism affecting the southeastaean Kaapvaal Craton
✍ Scribed by T Elworthy; B.M Eglington; R.A Armstrong; A.B Moyes
- Book ID
- 104354017
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 841 KB
- Volume
- 30
- Category
- Article
- ISSN
- 1464-343X
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✦ Synopsis
Biotite separates from Archaean granitoid lithologies on the Kaapvaal Craton north of the Proterozoic Namaqua-Natal Belt in south eastern South Africa exhibit Rb-Sr model dates of 967 + 24 Ma for samples from within 25 km of the present northern limit of the Proterozoic thrust front. Samples from further north (>50 km to 170 km) have model Rb-Sr dates of 2614+74 Ma. The younger dates are interpreted as dating cooling after northwards emplacement of Proterozoic crust onto the Kaapvaal Craton, whereas the older dates are presumed to relate to an Archaean metamorphic episode, possibly associated with intrusion of the post-Pongola granites.