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大别-苏鲁造山带和华北陆块东南缘中生代花岗岩具有弧型微量元素分布特征和富集的Sr-Nd-Hf同位素组成,表明它们来源于古老大陆地壳物质的重熔.这些花岗岩中普遍含有新元古代中期和三叠纪U-Pb年龄的继承锆石,分别与大别-苏鲁造山带超高压变火成岩原岩年龄和超高压变质年龄一致.部分花岗岩具有低的锆石18O值.SIMS微区原位O同位素分析揭示,具有新元古代和三叠纪U-Pb年龄的继承锆石也普遍亏损18O.新元古代U-Pb年龄和18O亏损是有效区分俯冲华南陆块与上覆华北陆块的鉴定性特征,表明俯冲华南陆壳是这些中生代花岗岩的源区物质.另外,这些花岗岩中还含有古元古代和太古代U-Pb年龄的继承锆石,特别是华北陆块东南缘中生代花岗岩含有-2.5 Ga的继承锆石,表明它们的岩浆源区既有华南陆壳物质,也有华北陆壳物质.
The Mesozoic granitoids in the Dabie-Sulu orogenic belt and the southeastern margin of the North China terrane have arc-shaped trace element distributions and enriched Sr-Nd-Hf isotope compositions indicating that they originated from the remelting of ancient continental crustal materials. The inherited zircons with mid-Neoproterozoic and Triassic U-Pb ages are consistent with the age and UHP metamorphic ages of UHP diagenetic igneous rocks in the Dabie-Sulu orogenic belt, respectively. Some granites have low zircon 18O values The in-situ O isotope analysis of the SIMS microfacies reveals that inherited zircons with Neoproterozoic and Triassic U-Pb ages also generally lost 18%. The Neoproterozoic U-Pb age and 18O depletion are effective for distinguishing the subducted South China block from the The identification of overburden in North China shows that the subducted South China continental crust is the source material of these Mesozoic granites.In addition, these granites also contain inherited zircons of Paleoproterozoic and Archean U-Pb ages, especially of North China The Mesozoic granites on the southeastern margin of the block contain inherited zircons of -2.5 Ga, indicating that they have both southern and southern continental crustal materials in their magmatic source areas.