Temporal evolution of the Angavo and related shear zones in Gondwana: Constraints from LA-MC-ICP-MS U–Pb zircon ages of granitoids and gneiss from central Madagascar

摘要: Abstract Granitoids of Neoproterozoic age are well exposed in the Precambrian basement rocks Madagascar, vicinity and within dextral Angavo shear zone (ASZ). Pre-kinematic granitoids, a syn-kinematic granite, granitic gneiss have been dated using Laser Ablation Multicollector Inductively Coupled Plasma Mass Spectrometry (LA-MC-ICP-MS). One pre-kinematic granitoid yields weighted mean 206 Pb/ 238 U igneous zircon crystallization 823.6 ± 6 Ma, second 756.6 ± 9 Ma 563 ± 11 Ma metamorphic age. A granite gives 549.8 ± 4 Ma, which points to time movement ASZ. protolith 732 ± 13 Ma records 558.8 ± 4 Ma Accordingly, ASZ was active associated with high-temperature metamorphism Angavo-Nondiana belt during Ediacaran. The late Proterozoic ages intrusions recorded by granites show that pre-tectonic were sheared ASZ, granulite–amphibolite facies events. These U–Pb data suggest link between Achankovil India, adjacent several proposed Gondwana reconstructions.