华北克拉通南缘下汤地区古元古代构造热事件——地球化学特征、锆石SHRIMP U-Pb定年和Hf同位素研究

发布时间：2019-03-04 12:44

【摘要】：本文报道了华北克拉通南缘鲁山县下汤地区早前寒武纪变质基底岩石的地球化学、锆石定年和Hf同位素组成。上太华岩群两个变质沉积岩样品的变质锆石年龄为1.91~1.93 Ga,由于变质作用强烈改造,碎屑锆石真正的形成年龄难以确定。碎屑锆石ε_(Hf)(t)和t_(DMW(CC))(Hf)分别为-0.26~10.41和2244~2958 Ma。一个变质辉长闪长岩样品的捕获锆石年龄为2.32 Ga,变质锆石年龄为1.93 Ga。捕获锆石的ε_(Hf)(t)和t_(DM2(CC))(Hf)分别为-1.79~2.22和2695~2940 Ma。两个片麻状奥长花岗岩样品的岩浆锆石和变质锆石年龄分别为1.93 Ga和1.92 Ga,岩浆锆石的ε_(Hf)(t)和t_(DM2(CC))(Hf)分别为-3.30~1.30和2481~2764 Ma。一个片麻状正长花岗岩样品的岩浆锆石和变质锆石年龄分别为1.93 Ga和1.92 Ga,岩浆锆石的ε_(Hf)(t)和t_(DM2(CC))(Hf)分别为-3.67~2.40和2415~2788 Ma。结合地球化学和前人研究结果,可得出如下结论:(1)上太华岩群形成时代形成于古元古代早期;(2)进一步支持了该区存在约2.3 Ga岩浆作用的认识;(3)发现广泛分布的1.91~1.93 Ga壳源奥长花岗岩和正长花岗岩;(4)确定1.91~1.94 Ga变质作用在该区广泛发育。
[Abstract]:This paper reports the geochemistry, zircon dating and Hf isotopic composition of early Precambrian metamorphic basement rocks in Xiatang area, Lushan County, southern margin of North China craton. The metamorphic zircon age of two metamorphic sedimentary rock samples from the Shangtai rock group is 1.91 to 1.93 Ga, because of the strong metamorphism, it is difficult to determine the true age of clastic zircon formation. The 蔚 _ (Hf) (t) and t _ (DMW (CC) (Hf) of clastic zircon are-0.26 and-0.26, respectively, 10.41 and 2244, and 2958 Ma., respectively. A metamorphic gabbro diorite sample has a capture zircon age of 2.32 Ga, and a metamorphic zircon age of 1.93 Ga.. The 蔚 _ (Hf) (t) and t _ (DM2 (CC) (Hf) of the captured zircon are-1.79? 2.22 and 2695? 2940 Ma., respectively. The magmatic zircon and metamorphic zircon ages of the two gneiss-like syenite samples are 1.93 Ga and 1.92 Ga, respectively. The 蔚 _ (Hf) (t) and t _ (DM2 (CC) (Hf) of the magmatic zircon are-3.30 and-3.30, respectively, and that of the metamorphic zircon are 2481 and 2764 Ma., respectively. The magmatic zircon and metamorphic zircon ages of a gneissic syenite sample are 1.93 Ga and 1.92 Ga, respectively. The 蔚 _ (Hf) (t) and t _ (DM2 (CC) (Hf) of the magmatic zircon are-3.67? 2.40 and 2415? 2788 Ma., respectively. Combined with geochemistry and previous research results, the following conclusions can be drawn: (1) the formation age of the Upper Taihua Group was formed in the early period of Gu Yuan, (2) the understanding of the existence of about 2.3 Ga magmatism in this area was further supported; (3) extensive distribution of 1.91 ~ 1.93 Ga crust-derived monzonitic granites and syenite are found, and (4) 1.91 ~ 1.94 Ga metamorphism is widely developed in this area.
【作者单位】：中国地质科学院矿产资源研究所国土资源部成矿作用与资源评价重点实验室;中国地质科学院地质研究所北京离子探针中心;中国地质大学;
【基金】：国家自然科学基金资助项目(编号:41472169) 基本科研业务费(编号:K1508) 中国地质调查局工作项目(编号:1212011220465,1212011120142,1212010811033,12120113013700)的成果~~
【分类号】：P597.3;P534.3

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