Protolith origin of the Lanling high-pressure metamorphic terrane in central Qiangtang, Tibet, reveals the subduction of the Permian-Triassic ocean island and abyssal submarine fan in the Paleo-Tethys Ocean

Tian, Yang1,2,3; Liang, Xiao1,2; Wang, Genhou1; Tang, Yu1; Chen, Shang1; Gao, Xi1; Yang, Bo1; Guo, Zhen3; Wang, Yaxi1,4; Wen, Junhao1,5

2023-09-01

10.1016/j.gr.2023.05.002

GONDWANA RESEARCH   影响因子和分区

1342-937X

1878-0571

Unraveling the protolith origin of high-pressure and low-temperature (HP-LT) metamorphic rocks is the key to understanding the tectonic evolution of active continental margins. A comprehensive study, including field observations, geochemical analyses and zircon U-Pb geochronological dating, was conducted on the Lanling HP-LT terrane to determine its protolith origin and the presubduction paleogeography of the Paleo-Tethys Ocean. The metabasites can be divided into two geochemical groups: Group A samples exhibit low TiO2 values (1.15-1.81 wt%) and subalkaline basalt affinity with rare earth element (REE) distribution patterns and trace element abundances similar to enriched mid-ocean ridge basalts (EMORB); Group B samples have higher TiO2 values (2.75-3.32 wt%) and show alkaline basalt affinity and ocean island basalt (OIB) geochemical signatures. Lanling metabasites are likely derived from a longdepleted mantle source combined with crustal contamination based on the following evidence: (1) positive eNd(t) values (+4.8 to +5.6) and a scattered distribution of Isr(t) values (0.704684 to 0.710999), (2) abundant Precambrian zircon grains, and (3) a volcanic arc trend in the tectonic discrimination diagram. Zircon U-Pb dating yields a timing of ca. 272-241 Ma for the protolith age of the Lanling eclogites. The protoliths of the OIB- and E-MORB-type metabasites in Lanling are postulated to be ocean island magmatites and basaltic crust of the Paleo-Tethys Ocean, respectively. Moreover, the Lanling quartzose schists contain only ancient detrital zircons with ages of >500 Ma and show protolith lithostratigraphy and provenance similar to those of the late Paleozoic clastic flysch in the South Qiangtang block (SQB). Based on the above observations and other geological evidence, a hypothetical model of the Permian- Triassic ocean island and adjacent abyssal submarine fan in the Paleo-Tethys Ocean is proposed to explain the protolith origin of the Lanling HP-LT terrane and the presubduction paleogeography in central Qiangtang. & COPY; 2023 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

HP-LT rocks central Qiangtang Protolith Provenance Geochemistry Paleo-Tethys Ocean

SCI

英语

其他

General Program Fund of the National Natural Science Foundation of China[42172225] ; Ministry of Education of the People's Republic of China[35832020077] ; China Geological Survey (CGS) : "1:50,000 regional geological surveys in the Qomo Ri and Rongma area of Tibet"["1212010818014","1212011221081"]

Geology

Geosciences, Multidisciplinary

WOS:001013575600001

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GEOSCIENCES

Web of Science

1.China Univ Geosci Beijing, Sch Earth Sci & Resources, 29 Xueyuan Rd, Beijing 100083, Peoples R China
2.China Univ Geosci Beijing, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China
3.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, Shenzhen, Peoples R China
4.Sichuan Geol & Mineral Bur, Chengdu 610213, Sichuan, Peoples R China
5.Adm & Protect Bur China Precambrian Prov Geol Nat, Yuxi, Peoples R China

Tian, Yang,Liang, Xiao,Wang, Genhou,et al. Protolith origin of the Lanling high-pressure metamorphic terrane in central Qiangtang, Tibet, reveals the subduction of the Permian-Triassic ocean island and abyssal submarine fan in the Paleo-Tethys Ocean[J]. GONDWANA RESEARCH,2023,121.

Tian, Yang.,Liang, Xiao.,Wang, Genhou.,Tang, Yu.,Chen, Shang.,...&Wen, Junhao.(2023).Protolith origin of the Lanling high-pressure metamorphic terrane in central Qiangtang, Tibet, reveals the subduction of the Permian-Triassic ocean island and abyssal submarine fan in the Paleo-Tethys Ocean.GONDWANA RESEARCH,121.

Tian, Yang,et al."Protolith origin of the Lanling high-pressure metamorphic terrane in central Qiangtang, Tibet, reveals the subduction of the Permian-Triassic ocean island and abyssal submarine fan in the Paleo-Tethys Ocean".GONDWANA RESEARCH 121(2023).