Late Mesozoic tectonic evolution of the central Bangong–Nujiang Suture Zone, central Tibetan Plateau

Study of molasse within the middle segment of the Bangong‐Nujiang suture zone, central Tibet: Constraints of ocean–continent transform

“…Therefore, from the gravel composition and the age distribution of debris zircons, it is not determined whether there is a source of Lhasa terrane. This could be caused by the bars composed of uplifted mountains which make the Zanzong Co area an intermontane basin, as previously reported (Li et al, 2017, 2019; Pan et al, 2012). In addition, the detrital zircon age patterns of the Jingzhushan Formation from other regions in BNSZ (Figure 9) also show that the Jingzhushan Formation was likely to be drawn from the southern Qiangtang magmatic arc, the South Qiangtang terrane and the intervening BNSZ (Huang, 2017; Li et al, 2017), which is accordant with this study at Zanzong Co area.…”

“…In addition, the detrital zircon age patterns of the Jingzhushan Formation from other regions in BNSZ (Figure 9) also show that the Jingzhushan Formation was likely to be drawn from the southern Qiangtang magmatic arc, the South Qiangtang terrane and the intervening BNSZ (Huang, 2017; Li et al, 2017), which is accordant with this study at Zanzong Co area. Besides, the detrital zircon age patterns of the Jingzhushan Formation from the Dong Co area (Li et al, 2017), the Nima area (Huang, 2017), the Dongqiao area (Huang, 2017) and the Zanzong Co area display a crossing disorderly form, partially, which further suggests intermontane environments and very near provenances (Li et al, 2019).…”

Mesozoic Subduction Accretion History in Central Tibet Constrained From Provenance Analysis of the Mugagangri Subduction Complex in the Bangong‐Nujiang Suture Zone

“…During Early to Middle Jurassic time, the Late Triassic Group 2 sandstones may have been incorporated into the north dipping Bangong‐Nujiang oceanic subduction complex (S. Li, Wang, et al, 2019; Zeng et al, 2016). In a progressive accretion model (e.g., Ernst et al, 2009; Seely et al, 1974), the Group 1 sandstone should be accreted beneath the Group 2 sandstone.…”

“…The Mugagangri Complex was first established in the Nima area (Figure 1b) as the Mugagangri Group and described as Middle Jurassic flysch (Wen, 1979). Recent studies show that the Mugagangri Complex consists of coherent sedimentary sequences of Qiangtang affinity and siliciclastic mélange that can be divided into several units, including the Early Cretaceous Zhaguo Formation, several Triassic to Jurassic subunits, the Middle Jurassic Gamulong Formation, Dongqiao‐Amdo mélange, Daru mélange, and Beila‐Naqu mélange (Fan, Li, Liu, et al, 2015; Huang et al, 2017; S. Li et al, 2017; C. Li, Wang, et al, 2019; S. M. Li et al, 2020; Sun et al, 2019; Zeng et al, 2016). The shallow marine Shamuluo Formation (Figure 2) is structurally juxtaposed against the Mugagangri Complex in the Najiangco area; it is composed of sandstone, shale, and limestone and was constrained to be Oxfordian to Kimmeridgian with recycled orogen‐derived provenance from the Qiangtang interior (Ma et al, 2018).…”

“…The Mugagangri Complex is exposed along a >1,500‐km‐long east‐west belt and consists of mainly siliciclastic‐matrix mélange, strongly dismembered formations, and coherent turbiditic sandstone sequences along the Bangong‐Nujiang suture zone in central Tibet (Figure 1a). Previous studies in the Gaize (Fan, Li, Liu, et al, 2015; Huang et al, 2017; S. Li, Ding, et al, 2017; Zeng et al, 2016), Nima (C. Li, Wang, et al, 2019), and Dongqiao (S. M. Li et al, 2020) areas (Figure 1a) concluded that all sandstones in the Mugagangri Complex were sourced from the Qiangtang terrane (Fan, Li, Liu, et al, 2015; Huang et al, 2017; S. Li, Ding, et al, 2017; Zeng et al, 2016). However, the tectonic setting in which clastic sedimentary rocks of the Mugagangri Complex were deposited is debated.…”