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超高压变质锆石在高压变质及退变质期间可发生少量Pb的连续扩散丢失,它不会显著破坏其~(207)Pb/~(238)U和~(206)Pb/~(235)U年龄的一致性,但却使它们小于~(207)Pb/~(206)Pb年龄.不含继承组分且普通Pb含量低的变质锆石~(207)Pb/~(206)Pb年龄,可能更接近超高压变质岩的峰期变质时代.报道了一组新的大别山超高压变质岩及其围岩的锆石U-Pb年龄数据,并给出峰期超高压变质时代为(228±2)Ma的结论.
Pb and ~ (238) U and ~ (206) Pb / ~ (235) U can not be significantly damaged by ultra-high pressure metamorphic zircon during the high-pressure metamorphism and retrogressive metamorphism. (207) Pb / ~ (206) Pb ages, and the metamorphic zircon ~ (207) Pb / ~ (206) Pb ages without inherited components and low normal Pb contents, May be closer to the peak metamorphic age of UHP metamorphic rocks.A series of U-Pb dating data of the UHP metamorphic rocks and their surrounding rocks in the Dabie Mountains are reported, and the epochs of UHP metamorphism during the peak period are (228 ± 2) Ma’s conclusion.