Genesis of granitoid batholiths of Peninsular Malaysia and implications for models of crustal evolution: Evidence from a NdSr isotopic and UPb zircon study

Nd, Sr and U-Pb isotopic data for the late Triassic West Coast Province batholiths and Permian to Triassic East Coast Province batholiths of Peninsular Malaysia allow estimates of the ages of the crustal fragments comprising the peninsula to be made. Initial ?_Nd and ?_Sr values for granitoids from the West Coast Province range from ?6 to ?10 and +160(0.716) to +660(0.751) respectively. Nd model ages calculated based on a depleted mantle evolution model (T_DM^Nd) range from 1300 Ma to 1800 Ma and are in general agreement with the mid-Proterozoic upper intersection ages of U-Pb zircon reverse discordia (1500–1700 Ma). Initial ?_Nd and ?_Sr values for granitoids from the East Coast Province range from ?0.8 to ?6 and +10(0.705) to +130(0.714) respectively. Calculated T_DM^Nd ages of 900–1400 Ma for these granitoids are comparable to two U-Pb zircon reverse discordia intercepts that yield 800 Ma and 1350 Ma. The general agreement of U-Pb zircon inheritance ages and T_DM^Nd ages are interpreted to correspond to the Proterozoic ‘crust formation’ ages of the continental fragments represented by the West Coast and East Coast batholithic provinces. Mid-Proterozoic (~ 1300–1900 Ma) ‘crust formation’ ages are commonly shown by other Phanerozoic continental margin plutonic and volcanic belts. The ubiquitous mid-Proterozoic ‘crust formation’ ages and the absence of Archaean signatures suggest voluminous juvenile additions to the continental crust in the mid-Proterozoic. Such ages at continental margins would imply that many continental blocks had achieved very much their present-day extent by the mid-Proterozoic.