Neoproterozoic and Cambro-Ordovician magmatism: episodic growth and reworking of continental crust, Himachal Himalaya, India

U-Pb SHRIMP and LA-MC-ICP-MS zircon dates from Dalhousie and Dhauladhar granite yield weighted mean ages of 900 to 700 Ma for magmatic cores. The rim has an age of 460 Ma age, representing the time of reworking of early Neoproterozoic bodies during Cambro-Ordovician time. The plutons are composed of granite, monzogranite, and granodioritic having a peraluminous character with pronounced Eu anomaly. Higher Rb content and Rb/Sr ratio along with REE enrichment in Dalhousie granite show that the body is more evolved than Dhauladhar granite. New U-Pb data from Dalhousie and Dhauladhar areas suggest that Cambro-Ordovician continental magmatism took place within the Greater India by reworking of already existing Neoproterozoic granite. These two magmatic episodes can be correlated with the amalgamation of Gondwanaland over granite that formed during the Rodinia break-up.