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恒山麻粒岩相地体由英云闪长质-奥长花岗质-花岗闪长质(TTG)片麻岩和少量基性高压麻粒岩块体组成.对两个TTG片麻岩样品进行LA-ICP-MS锆石U-Pb定年得到其变质锆石年龄为1916.7±9.9 Ma和1850~1930 Ma,残留岩浆锆石年龄~2.5 Ga,两类锆石均为重稀土富集型稀土配分特征.在含ZrO2体系中进行P-T视剖面图模拟表明在固相线以上变质作用中锆石随着熔体含量增加而熔解,只在降温过程中随着熔体结晶而生长,因此变质新生锆石只能记录麻粒岩相的退变质年龄.由此推测恒山麻粒岩地体在1.85~1.93 Ga期间,处于发生缓慢抬升冷却的中地壳伸展环境,而与高压麻粒岩相峰期变质阶段对应的碰撞造山事件发生的时间应该更早.
The Hengshan granulite facies body is composed of diagenetic dioritic-olivine-granodioritic (TTG) gneisses and a few of basic high-pressure granulite blocks.For two TTG gneisses The LA-ICP-MS zircon U-Pb zircon dating of the metamorphic zircons is 1916.7 ± 9.9 Ma and 1850-1930 Ma, and the age of residual magmatic zircons is ~ 2.5 Ga. Both zircons are heavy rare earth rich Rare earth with the characteristics of the zirconia system containing Zr in the cross-section diagram of the simulation shows that the deformation of the zircon above the solidification line with increasing melt content of the melt, only in the cooling process with the melt crystal growth and therefore deterioration Cenozoic zircons can only record the metamorphic ages of granulite facies, suggesting that the Hengshan granulite body is in a slowly crusting mid-crust extensional environment from 1.85 to 1.93 Ga, The occurrence of collisional orogeny events corresponding to the metamorphic phase should be earlier.