Oceanic-type high-temperature eclogites from Hainan Island, South China: General characteristics and unsolved problems

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

“…A large number of Late Permian-Early Triassic magmatic events, such as the Xinanzhai monzogranite at 251.6 ± 2.0 Ma and the Tongtiange leucogranite at 247.5 ± 2.2 Ma, occurred near the Ailaoshan suture belt, indicating that the magmatic rocks near the Ailaoshan suture belt are related to Indosinian orogeny (Liu et al, 2015). Consistent with the discovery that the Middle-Late Triassic volcanic rock sequence in the Jinshajiang-Ailaoshan area is covered by a conglomerate unconformity of the Upper Triassic Yongwanshui Formation, the Middle Triassic Lizhigou acidic magmatic F I G U R E 1 4 Geotectonic unit division model of Hainan Island (a) according to Long et al, 2022; according to Tang, 2010; according to Liu et al, 2006; according to Liu, Hu, Chen, et al, 2021;Liu, Hu, et al, 2022. rock in the southern part of Hainan Island is covered by an overlying conglomerate angular unconformity of the Upper Triassic (Gou et al, 2019;He et al, 2020). The detrital zircons obtained by Liu, Hu, Chen, et al (2021) in the southeastern sea area of Hainan Island recorded a metamorphic age of approximately 250 Ma in the Indosinian period, comparable with the high-grade metamorphism of 247-253 Ma in northern Vietnam (Owada et al, 2007) Halpin et al, 2016;Liu, Peng, et al, 2022;Xu, Xia, Lai, Long, & Huang, 2019); (d) southwest margin of the SCB (data from Chai et al, 2022;Duan et al, 2018;Hu et al, 2017;Liu, Peng, et al, 2022;Xu, Xia, Lai, Long, & Huang, 2019;Yang et al, 2012a); (e) southeast margin of the SCB (Hu et al, 2015;Kong, Xu, Tao, et al, 2022;Xu et al, 2018).…”

“…Detrital zircons of this age group are also rare in clastic rock from the Truong Son belt and the Kontum Massif in the IB (Kenta et al, 2021;Wang, Lin, Faure, Lepvrier, et al, 2021;. However, detrital zircons aged 750-1000 Ma were present in the SCB (Liu, Hu, Chen, et al, 2021;Wang et al, 2019;Wang, Wen, et al, 2018 (Figure 6a) and a detrital zircon age group of 417-501 Ma is present in the Silurian strata of Hainan Island (Long et al, 2022). We speculate that the detrital zircons in the sample with a secondary age peak of 418 ± 7 Ma originated from the recycling of the early Palaeozoic strata.…”

“…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…”

“…Second, although scholars have a consistent understanding of the collision and amalgamation of the southern and northern Hainan terranes during the Early-Middle Triassic (ca. 250 Ma) (Li et al, 2005;Liu, Hu, Chen, et al, 2021;Owada et al, 2007;Peng et al, 2004;Yun et al, 2004;Zhang et al, 2011), their opinions on the collision and amalgamation methods of the Hainan terranes during this period continue to differ.…”

“…A few scholars believe that it was controlled by the subduction of the IB from south to north (Wang, Zhong, et al, 2018;Yan et al, 2017), whereas others believe that it was controlled by the subduction of the SCB from north to south (Halpin et al, 2016;Liu, Hu, et al, 2022;Liu, Hu, Chen, et al, 2021).…”