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Remnants of middle Triassic oceanic lithosphere in the western Indus–Tsangpo suture zone, southwestern Tibet
Author(s) -
Liu Qiang,
Liu Feng,
Li Hualiang,
Zong Keqing
Publication year - 2021
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12495
Subject(s) - geology , fibrous joint , ophiolite , gabbro , gondwana , terrane , lithosphere , mafic , paleontology , zircon , tethys ocean , oceanic crust , cretaceous , geochemistry , basalt , tectonics , subduction , medicine , anatomy
Discontinuous ophiolites within the Indus–Tsangpo suture zone (ITSZ) in southern Tibet represent remnants of Neo‐Tethyan oceanic lithosphere, which are considered to have formed during the late Jurassic to early Cretaceous. We report field observations, petrological and geochronological data for some mafic intrusions in a tectonic mélange in the southern ophiolitic belt of the western ITSZ. Zircon from a gabbro yields an age of 243 ± 1 Ma with ε Hf ( t ) values of +7.9 to +13.2. Rare earth element (REE) pattern of this rock resembles that of normal mid‐ocean ridge basalt. We suggest that such gabbro and surrounding mafic–ultramafic rocks represent the remnants of middle Triassic oceanic lithosphere in the ITSZ. Our findings indicate that the Neo‐Tethys Ocean between India and the Lhasa terrane existed from at least the middle Triassic, contrasting with the commonly held view that the Neo‐Tethys Ocean opened along the northern edge of Gondwana during the late Triassic–early Jurassic.