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南黄海千里岩岛榴辉岩对进一步深入完善大别-苏鲁造山带的研究具有重要意义.岩相学和矿物学研究显示榴辉岩主要经历了俯冲进变质(Ⅰ)、峰期榴辉岩相变质(Ⅱ)、角闪岩相退变质(Ⅲ)和绿片岩相退变质(Ⅳ)阶段.各阶段的温压条件分别为:Ⅱ阶段T=806.3℃,P=3.32GPa;Ⅲ阶段T=658.68℃,P=0.78GPa;Ⅳ阶段T<550℃,P<0.3GPa.锆石SHRIMP U-Pb测年指示千里岩榴辉岩的原岩形成于新元古代(约747±19Ma),超高压变质作用发生在早三叠世(约241.1±1.5Ma),角闪岩相退变质发生在三叠纪末(约205.8Ma).在此基础上,建立了千里岩岛榴辉岩的P-T-t演化轨迹,反映出榴辉岩经历了2个折返阶段.这一P-T-t轨迹整体上与苏鲁地区榴辉岩类似,指示该区所在的千里岩隆起区是苏鲁造山带在海区的延伸.
The eclogites of the Centipede Islands in the South Yellow Sea are of great significance to further improve the study of the Dabie-Sulu orogenic belt.The petrographic and mineralogical studies show that the eclogites mainly experienced subduction and metamorphism (Ⅰ), peak euclides Metamorphism (Ⅱ), amphibolite facies metamorphism (Ⅲ) and greenschist facies metamorphism (Ⅳ) .The temperature and pressure conditions of each stage are as follows: Ⅱ = T = 806.3 ℃, P = 3.32GPa; T = 658.68 ℃, P = 0.78GPa; Stage Ⅳ <550 ℃, P <0.3GPa. The zircon SHRIMP U-Pb dating indicates that the protolith of the Qianliyan eclogites formed in Neoproterozoic (about 747 ± 19Ma) , UHP metamorphism took place in the Early Triassic (about 241.1 ± 1.5Ma), and amphibolite facies metamorphism occurred at the end of Triassic (about 205.8Ma). On this basis, the Cretaceous eclogite Of the PTt evolution trajectory, reflecting the eclogite experienced two stages of reentry.This PTt trajectory is generally similar to the eclogites in the Sulu area, indicating that the area where the Chillite uplift is the extension of the Sulu orogen in the sea area .