Reply to Comment by W.‐Y. Chen et al. on “Sedimentary and Tectonic Evolution of the Southern Qiangtang Basin: Implications for the Lhasa–Qiangtang Collision Timing”

Early Cretaceous (∼138–134 Ma) Forearc Ophiolite and Tectonomagmatic Patterns in Central Tibet: Subduction Termination and Re‐initiation of Meso‐Tethys Ocean Caused by Collision of an Oceanic Plateau at the Continental Margin?

“…Although many ophiolites lack complete successions and are preserved in a highly dismembered condition, the association comprising ultramafic rocks at the base, overlain by layered/nonlayered gabbroic rocks and extrusive basaltic rocks with MORB‐like composition, and a cover of pelagic sediments, is essential to confidently identify an ophiolite (e.g., Robertson, 2002). Thus, the existence of Early Cretaceous ophiolites within the BNSZ has been contested because the arguments are all based on Early Cretaceous OIB‐type rocks that lack spatial association with mantle peridotite or with MORB‐type rocks (e.g., A. Ma & Hu, 2018). The Early Cretaceous cumulate and isotropic gabbros examined in this study show MORB‐like trace‐elemental and isotopic features (Figures 5–7) and are spatially associated with mantle peridotite and chert‐bearing basalt (Figures 2 and S2), which collectively constitute an ophiolite sequence.…”

“…Conversely, researchers supporting the Jurassic collision model argue that these OIB‐type rocks represent partial melts of ascending sub‐lithospheric mantle in a post‐collisional extensional setting rather than Early Cretaceous oceanic crustal materials (P. Y. Hu et al., 2017; A. Ma & Hu, 2018; Zhu et al., 2016). As summarized in Table 1, studies using different approaches to solve this problem appear to fall in either of the two proposed models, and the lack of consensus stems mainly from the uncertainty regarding whether Early Cretaceous ophiolite occurs in the BNSZ (e.g., W. Y. Chen et al., 2018; A. Ma & Hu, 2018; Shi et al., 2020). Therefore, whether Early Cretaceous oceanic crust exists within the BNSZ is crucial to our understanding of the style and timing of closure of the Meso‐Tethys Ocean.…”