Two episodes of Eocene mafic magmatism in the southern Lhasa terrane imply an eastward propagation of slab breakoff

• The gabbro was originated from metasomatized lithospheric mantle. hornblende formed mixing of asthenosphere and slab breakoff propagated eastward under the Lhasa terrane in Paleocene-Eocene. Past geodynamic events can be reconstructed using spatial temporal patterns geochemical variability igneous rocks. Here we apply this principle to define timing geometry Neo-Tethyan after India-Asia collision. Two episodes mafic magmatism (?53 Ma ? 48 Ma) are preserved Quxu area southern (SL). We present their whole-rock geochemistry, zircon U-Pb ages, situ Hf isotope ratios. early exhibits typical arc basalt characteristics, including enrichment large-ion lithophile elements (LILEs), depletion high-field strength (HFSEs), radiogenic Nd isotopes, implying that they were by partial melting In comparison gabbro, late (?48 contains higher contents HFSEs (e.g., Nb, Zr) relatively less suggesting interaction between enriched sub-continental mantle asthenospheric It is likely upwelling reached central SL around 50 tore off at time. distribution rocks across whole show transition hence, presumably, tearing slab, along collision zone throughout Paleocene-Eocene