Journal article

Geochemistry and geochronology of the Rathjen Gneiss: implications for the early tectonic evolution of the Delamerian Orogen

J Foden, M Sandiford, J Dougherty-Page, I Williams

AUSTRALIAN JOURNAL OF EARTH SCIENCES | TAYLOR & FRANCIS LTD | Published : 1999

Abstract

The Rathjen Gneiss is the oldest and structurally most complex of the granitic intrusives in the southern Adelaide Fold-Thrust Belt and therefore provides an important constraint on the timing of the Delamerian Orogen. Zircons in the Rathjen Gneiss show a complex growth history, reflecting inheritance, magmatic crystallisation and metamorphism. Both single zircon evaporation ('Kober' technique) and SHRIMP analysis yield best estimates of igneous crystallisation of 514 ± 5 Ma, substantially older than other known felsic intrusive ages in the southern Adelaide Fold-Thrust Belt. This age places an older limit on the start of the Delamerian metamorphism and is compatible with known stratigraphic..

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