Journal article

RB/SR DATING OF DIFFERENTIATED CLEAVAGE FROM THE UPPER ADELAIDEAN METASEDIMENTS AT HALLETT COVE, SOUTHERN ADELAIDE FOLD BELT

S TURNER, M SANDIFORD, T FLOTTMANN, J FODEN

JOURNAL OF STRUCTURAL GEOLOGY | PERGAMON-ELSEVIER SCIENCE LTD | Published : 1994

Abstract

Upper Adelaidean psammites from the foreland part of the Late Proterozoic Adelaide fold belt at Hallett Cove have suffered one major deformation which produced upright folds that plunge gently south. Axial to these folds is a well developed differentiation cleavage inferred to have resulted from constant volume, plane-strain deformation by solution transfer and now defined by alternating P- (phyllosilicate-rich) and Q- (quartz-rich) domains. Geochemical analyses show that cleavage development resulted in a 2-4-fold fractionation of Rb/Sr between the P- and Q-domains; thus the age of deformation is datable and isotopic analyses show the P- and Q-domains form a 531 ± 32 Ma isochron. This age i..

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