2020/05/14 by Nan Xu, Cailai Wu, Cai-lai Wu +5 · 16 citations
Earth and Planetary Sciences · #Continental arc #Continental crust #Crust #Geochemistry #Geological and Geochemical Analysis #Geology #High-pressure geophysics and materials #Magmatism #Oceanic crust #Paleontology #Paleozoic #Pluton #Subduction #Tectonics #Zircon #earthquake and tectonic studies
paper · doi:10.1017/s0016756820000126
published in Geological Magazine 157(7), 1121-1143 (Cambridge University Press)
openalex publication_date 2020/05/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
Abstract The South Altyn Orogenic Belt (SAOB) is one of the most important orogenic belts in NW China, consisting of the South Altyn Continental Block and the Apa–Mangya Ophiolitic Mélange Belt. However, its Palaeozoic tectonic evolution is still controversial. Here, we present petrological, geochemical, zircon U–Pb and Lu–Hf isotopic data for the Mangya plutons with the aim of establishing the Palaeozoic tectonic evolution. We divide the Early Palaeozoic magmatism in the Apa–Mangya Ophiolitic Mélange Belt into four episodes and propose a plate tectonic model for the formation of these rocks. During 511–494 Ma, the South Altyn Ocean (SAO) was in a spreading stage, and some shoshonite series, I-type granitic rocks were generated. From 484 to 458 Ma, the oceanic crust of the SAO subducted northward, accompanied by large-scale magmatic events resulting in the generation of vast high-K calc-alkaline series, I-type granitic rocks. During 450–433 Ma, the SAO closed, and break-off of the subducted oceanic slab occurred, with the generation of some high-K calc-alkaline series, I–S transitional type granites. The SAOB was in post-orogenic extensional environment from 419 to 404 Ma, and many A-type granites were generated.