Continental reworking during overprinting orogenic events, southern Prince Charles Mountains, east Antarctica

Abstract

In situ electron microprobe monazite dating and mineral equilibria modelling of amphibolite-granulite-facies metapelites from the southern Prince Charles Mountains, East Antarctica has been carried out to unravel the P-T conditions, spatial extent and structural style of two overprinting orogenic records. This study shows that: (1) rocks of the northern Palaeoproterozoic Lambert Complex were pervasively reworked at peak conditions (6·5-7·1 kbar and 790-810°C) during the Early Neoproterozoic Rayner orogenic event; (2) rocks of the southern Lambert Complex experienced pervasive deformation and metamorphism at peak conditions (5·8-6·1 kbar and 625-635°C) during Early Palaeozoic Prydz orogenic activity; (3) in regions of the Lambert Complex reworked during the Rayner orogenic event, Prydz-aged orogenesis was highly localized. The distribution of orogenic activity pertaining to the Rayner and Prydz orogenic events in the southern Prince Charles Mountains can be attributed to (1) the development of a southward directed (current coordinates) orogenic front that propagated from an Early Neoproterozoic collision between India and Antarctica, and (2) rock fertility (i.e. availability of free fluid) during Early Palaeozoic intraplate orogenesis that was driven by far-field stresses generated by a collision of India-Antarctica with the Mawson Craton. © The Author 2009. Published by Oxford University Press. All rights reserved.