Abstract: A compilation of 290 zircon U–Pb ages of intrusive rocks indicates that the Gangdese Batholith insouthern Tibet was emplaced from c. 210 Ma to c. 10 Ma. Two intense magmatic pulses within the batholithoccur at: (1) 90 ± 5 Ma, which is restricted to 89–94° E in the eastern segment of the southern Lhasa subterrane;and (2) 50 ± 3 Ma, which is widespread across the entire southern Lhasa subterrane. The latter pulse was fol-lowed by a phase of widespread but volumetrically small, dominantly felsic adakitic intrusive rocks at 16 ±2 Ma. The Linzizong volcanism in the Linzhou Basin was active from 60.2 to 52.3 Ma, rather than 69–44 Ma as previously estimated. During 120–75 Ma, Gangdese Batholith magmatism migrated from south tonorth, arguing against rollback of the downgoing, north-dipping Neo-Tethyan oceanic lithosphere for the gen-eration of the 90 ± 5 Ma magmatic pulse. Petrological, geochemical and metamorphic data indicate that thispulse was likely to have been generated through subduction of the Neo-Tethyan oceanic ridge lithosphere. Sub-sequent Gangdese Batholith magmatism propagated both south and north during 70–45 Ma, and fnally concen-trated at the southern margin of the Lhasa Terrane at 45–30 Ma. The enhanced mafic magmatism since c. 70 Ma,magmatic flare-up with compositional diversity at c. 51 Ma and increased magmatic temperature at 52–50 Maare interpreted as the consequences of slab rollback from c. 70 Ma and slab breakoff of the Neo-Tethyan oceaniclithosphere that began at c. 53 Ma. The India–Asia convergence was driven by Neo-Tethyan subduction with anormal rate of convergence at 120–95 Ma, ridge subduction at 95–85 Ma, then subduction of a young and buoy-ant oceanic lithosphere after ridge subduction with rate deceleration at 84–67 Ma, Deccan plume activity andslab rollback with rate acceleration at 67–51 Ma, slab breakoff for sudden drop of the convergence rate at c.51 Ma, and fnally the descent of the high-density Indian continental lithosphere beneath Asia since c. 50 Ma.

文章信息：Zhu, D.C.*, Wang, Q., Chung, S.L., Cawood, P.A., Zhao, Z.D., 2018. Gangdese magmatism in southern Tibet and India-Asia convergence since 120 Ma. TRELOAR, P.J. & SEARLE, M.P. (eds.) Himalayan Tectonics: A Modern Synthesis. Geological Society, London, Special Publications 483, https://doi.org/10.1144/SP483.14