Abstract
Our two newly obtained high-quality 40Ar/39Ar ages suggest that the high-K volcanic rocks of the Lawuxiang Formation in the Mangkang basin, Tibet were formed at 33.5 ± 0.2 Ma. The tracing of elemental and Pb-Sr-Nd isotopic geochemistry indicates that they were derived from an EM2 enriched mantle in continental subduction caused by transpression. Their evidently negative anomalies in HFSEs such as Nb and Ta make clear that there is an input of continental material into the mantle source. The high-K rocks at 33.5 ± 0.2 Ma in the Mangkang basin may temporally, spatially and compositionally compare with the early one of two-pulse high-K rocks in eastern Tibet distinguished by Wang J. H. et al., implying that they were formed in the same tectonic setting.
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Zhang, H., He, H., Wang, J. et al. 40Ar/39Ar chronology and geochemistry of high-K volcanic rocks in the Mangkang basin, Tibet. Sci. China Ser. D-Earth Sci. 48, 1–12 (2005). https://doi.org/10.1360/03yd0125
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DOI: https://doi.org/10.1360/03yd0125