Role of the Kerguelen mantle plume in breakup of eastern Gondwana: Evidence from early cretaceous volcanic rocks in the eastern Tethyan Himalaya

To better understand the breakup mechanism of eastern Gondwana, U-Pb Zircon geochronological and wholerock geochemical studies were performed on the Zhela and Weimei formations volcanic rocks in the Zhuode area of the eastern Tethyan Himalaya. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb dating of zircons yielded 206Pb/238U ages of ~135-130 Ma, indicating that the volcanic rocks from Zhela and Weimei formations erupted during the Early Cretaceous. Whole rock analyses of major and trace elements show that the volcanic rocks are characterized by high content of TiO2 (1.84 wt%-4.03 wt%) and P2O5 (0.29 wt%-0.61 wt%), highly fractioned in LREE/HREE [(La/Yb)N = 9.12-14.53], and most of them have no obvious anomaly of Eu. The characteristic, highly enriched HFSE with no obvious anomaly of Nb and Ta, is similar to those of alkali basalts originated from the Kerguelen mantle plume. Our geochemical and geochronological results, combined with recent paleomagnetic results show that the original erupted position of the Zhela and Weimei formations volcanic rocks was just located in the center of the presently Kerguelen mantle plume, and support that the Kerguelen mantle plume led to the breakup of eastern Gondwana.