Evolution of the Bangong–Nujiang Tethyan ocean: Insights from the geochronology and geochemistry of mafic rocks within ophiolites

Sedimentary and tectonic evolution of the southern Qiangtang basin: Implications for the Lhasa‐Qiangtang collision timing

“…This interpretation is consistent with geochemical data on ophiolites of the Bangong‐Nujiang suture, which are mid‐ocean ridge basalt‐like suprasubduction‐zone ophiolites enriched in light rare earth elements and large‐ion lithophile element and depleted in Nb and Ta [ Huang et al , ; T. Liu et al , ; Wang et al , ; Xia et al , ]. The Bangong‐Nujiang ophiolites in Dongqiao are dated between 190 and 180 Ma, indicating an Early Jurassic onset of oceanic subduction [ T. Liu et al , ; Wang et al , ]. This ophiolite formation process may be compared with that of the Xigaze fore‐arc ophiolite [ Maffione et al , ], and is consistent with our interpretation of the southern Qiangtang basin as a fore‐arc basin.…”

“…The Amdo basement, between two segments (represented by Amdo ophiolite in the north and Yila ophiolite in the south) of the Bangong‐Nujiang suture zone [ Institute of Tibetan Geological Survey , ; Wang et al , ; Zhu et al , ] (Figure b), was thus tentatively interpreted as a microcontinent [ Chen et al , ; Guynn et al , ; X. R. Zhang et al , ; Zhu et al , ]. It consists of orthogneiss crystallized at 915–840 Ma and 530–470 Ma [ Guynn et al , , ], metasedimentary rocks bearing zircons showing affinity with the Qiangtang block [ Guynn et al , ; Zhu et al , ] and Lower‐Middle Jurassic granitoids (185–170 Ma) [ Guynn et al , ; D. L. Liu et al , ].…”

“…In the east at Dengqen, radiolarian chert overlying the ophiolite contains Late Triassic fossils [ Wang et al ., , ], but the gabbro and leucogabbro yielded zircons dated 178 Ma and 164 Ma, respectively [ Wang et al , ]. In Dongqiao, radiolarian chert associated with the ophiolite is Jurassic in age [ Wang , ], and gabbro yielded zircon with U‐Pb ages between 190 and 184 Ma [ Huang et al , ; T. Liu et al , ; Wang et al , ; Xia et al , ]. The ophiolite formed between 167 and 161 Ma in the central part at Gaize [ J. F. Li et al , ; Wang et al , ; Yuan et al , ; Zhang et al , ], and between 169 and 162 Ma in Ritu to the west [ Liu et al , ; Shi , ; Wang et al , ].…”

“…In Dongqiao, radiolarian chert associated with the ophiolite is Jurassic in age [ Wang , ], and gabbro yielded zircon with U‐Pb ages between 190 and 184 Ma [ Huang et al , ; T. Liu et al , ; Wang et al , ; Xia et al , ]. The ophiolite formed between 167 and 161 Ma in the central part at Gaize [ J. F. Li et al , ; Wang et al , ; Yuan et al , ; Zhang et al , ], and between 169 and 162 Ma in Ritu to the west [ Liu et al , ; Shi , ; Wang et al , ]. Abundant ocean island basalt (OIB)‐type basalts interpreted as seamounts [ Fan et al ., , ; Wang et al , ; Zhu et al , ] or an oceanic plateau [ K. J. Zhang et al , ] occur in Tarenben and Duoma northeast of Selingco (Figure b) [ Zhu et al , ], Nadong between Nima and Gaize [ Fan et al , ], and Zhonggang near Gaize [ Fan et al , ].…”

Middle Jurassic MORB-type gabbro, high-Mg diorite, calc-alkaline diorite and granodiorite in the Ando area, central Tibet: Evidence for a slab roll-back of the Bangong-Nujiang Ocean

“…The suture zone is made up of a discontinuous belt of flysch, mélange and ophiolitic fragments (Kapp et al, 2003;B.D. Wang et al, 2016;K.J.…”