Detrital zircon U–Pb age constraints on the Meso-Tethys Ocean closure in SE Asia

Abstract

The location of the Meso-Tethyan suture in Southeast (SE) Asia is ambiguous due to the strong overprint by the later India-Asia collisional tectonics. For the SE Asian extension of the Meso-Tethyan Bangong-Nujiang Suture (BNS) in Tibet, the two main candidates are the Longling-Ruili Suture (between the Tengchong and Baoshan blocks) and the Myitkyina ophiolite belt. Here, we present new detrital zircon U-Pb ages from high grade metasedimentary rocks of the Gaoligong Group, which is considered to be the basement of the Tengchong block located between the Longling-Ruili Suture and Myitkyina ophiolite belt. Our data suggest that the Gaoligong Group contains Cambrian, Triassic and Cretaceous zircons and is not a Precambrian basement, with a diagnostic age population peak at ∼1110 Ma. This peak is comparable to the ∼1170 Ma peak reported in the Australia-derived blocks (e.g., Lhasa and West Australia). Such similarities, as well as the similarities in stratigraphy, paleobiogeography, and magmatic history in the Tengchong block, suggest that the Tengchong block was located adjacent to the northern Australia margin in Gondwana, and was most likely linked with the Lhasa block (southern Tibet) since the Early Paleozoic. Thus, the Longling-Ruili Suture likely represents the continuation of Meso-Tethyan BNS in SE Asia. Supplementary material at https://doi.org/10.6084/m9.figshare.c.6266924

Closing of the east Palaeo‐Tethys Ocean: Source–sink records from Middle Triassic sediments, Hainan Island, China

“…By comparing detrital zircon U–Pb ages and MDS analysis of Middle Triassic strata in central Vietnam, near the Ailaoshan Fault and southwestern and southeastern SCB, it can be inferred that both north‐to‐south and south‐to‐north subduction occurred between the South and North Hainan terranes. This is consistent with the bipolar subduction model of the Ailaoshan Ocean proposed in recent studies (Mo et al, 2023; Xia et al, 2020; Xu et al, 2022; Xu, Xia, et al, 2020; Xu, Xia, Lai, Long, & Huang, 2019; Xu, Xia, Lai, Zhou, & Ma, 2019). The Jinshajiang‐Ailaoshan‐Songma suture zone extends into the CQF, indicating that the eastern segment of the Palaeo‐Tethys Ocean controlled the collision and assembly of the South and North Hainan Islands.…”

“…He, Wang, Xin, and Zhang (2018) found Permian andesites reflective of a MORB source with the input of a slab-derived component in a continental back-arc basin setting. The discovery of Carboniferous eclogite and metamorphic complex in the Mulantou area in the northeast corner of Hainan Island (Liu, Hu, et al, 2022;Liu, Hu, Chen, et al, 2021) (Mo et al, 2023;Xia et al, 2020;Xu et al, 2022;Xu, Xia, et al, 2020;Xu, Xia, Lai, Long, & Huang, 2019;Xu, Xia, Lai, Zhou, & Ma, 2019). The Jinshajiang-Ailaoshan-Songma…”

“…Zircons are commonly observed in rocks. Considering their strong resistance to weathering and abrasion, they can be used to reproduce the tectonic setting and evolution of source areas and to restore the evolutionary history of sedimentary basins and other geological issues (Dickinson, 1979; Guo et al, 2017; Mo et al, 2023; Peng et al, 2017; Xu, Du, & Yang, 2007; Xu, Xia, et al, 2007; Xu, Xia, Lai, Long, & Huang, 2019). In this study, we investigated the U–Pb ages of detrital zircons from the Middle Triassic Lingwen Formation on the east side of central Hainan Island.…”