Petrogenesis of Paleo-Mesoproterozoic mafic rocks in the southwestern Yangtze Block of South China : Implications for tectonic evolution and paleogeographic reconstruction
Three episodes of mafic magmatism are identified by zircon and baddeleyite U-Pb dating at 2299 ± 17 Ma, 1703 ± 8 Ma and 1511 ± 14 Ma in the southwestern Yangtze Block. These mafic rocks have tholeiitic compositions with enrichment of LILE but an absence of Nb, Ta, Zr, Hf anomalies, features similar to E-MORB. They have La/Ta (