Lithospheric extension of the accretionary wedge: An example from the Lanling high-pressure metamorphic terrane in Central Qiangtang, Tibet

Deciphering the exhumation mechanism of high-pressure−low-temperature (HP-LT) metamorphic rocks can provide important insights into tectonic evolution oceanic subduction zones at active continental margins. Here, we present a multidisciplinary study examining tectonics Permo−Triassic eclogite-bearing HP-LT terranes Central Qiangtang belt (CQMB) in central Tibetan Plateau. Field geological relations and microscopic observations show that Lanling area are separated from epimetamorphic late Paleozoic ophiolite mélange hanging wall by low-angle detachment faults primarily exhibit five stages deformation. The were exhumed as core complex pervasive synexhumation top-to-the-SW -S shear structures. results petrological mineralogical analysis pseudosection modeling retrograde eclogites indicate these characterized mineral growth pulses with hairpin-type decompressional pressure-temperature trajectories. A compilation previous geochronological data our 40Ar/39Ar dating minerals bands continuous ca. 244−215 Ma prior to collision between North Block (NQB) South Block. Moreover, CQMB is likely an autochthonous accretionary wedge resulting northward Paleo-Tethys Ocean beneath NQB. Combined 243−230 mantle upwelling north Lanling, infer CQMB, namely, Ocean, experienced Middle−Late Triassic lithospheric extension NW-SE direction.