Abstract Granitic magmatism related to the collisional orogenic belt provides important information for the evolution of continental crust. We performed petrological, geochemical and zircon U-Pb-Hf isotopic studies on four granitoid samples from the Guyang Changshengqu goldfield, Daqingshan area, Khondalite Belt, North China Craton. The zircon U-Pb dating results indicate that the granitoids emplaced at 1950±11 Ma, 1935±12 Ma, 1846±11 Ma, and 1812±8.6 Ma, represent two periodic granitic magmatism in the Daqingshan area. The 1.95 and 1.93 Ga granites exhibit high SiO2, K2O, and Na2O contents with high Sr/Y and (La/Yb)N ratios, but low MgO, Cr, and Ni contents, indicating that they were produced by the partial melting of a thickened lower crust under relatively high-pressure conditions. The granites show negative-dominated zircon eHf(t) values (-5.7–1.9), and their zircon TDM2(Hf) values range between 2.9 and 2.5 Ga, indicating an ancient crust source with minor juvenile crustal material involved. The 1.85 and 1.81 Ga quartz monzonites exhibit high SiO2, K2O, Na2O, Zr, Nb, Ce, and Y but low MgO, Cr, and Ni contents, with high Ga/Al and FeOt/(FeOt + MgO) ratios, indicating an A-type granite affinity. The whole-rock geochemistry suggests that they were formed by dehydration re-melting of TTG and quartz diorite at high temperatures and shallow depths. The quartz monzonites show homogeneous eHf(t) values (-10.6–-6.1) and the zircon TDM2(Hf) values range between 3.0 and 2.8 Ga, suggesting that they were derived from a Neoarchean ancient crust. The 1.95–1.93 Ga adakitic magmatism is associated with the 1.93–1.92 Ga mafic magmatism and UHT metamorphic in the eastern part of the Khondalite Belt; this suggests a tectonic transition from collisional compression to post-collisional extension. The 1.85–1.81Ga A-type granitic magmatism indicates evident continental crust thinning and asthenospheric upwelling. The two unrelated magmatism are possibly induced by two collisional events from the Khondalite Belt and the Trans-North China Orogen, respectively. The collision of the western and eastern blocks at ca. 1.85 Ga may have played an important role in the A-type quartz monzonites origin and influenced the crustal evolution as far as the Daqingshan area in the Khondalite Belt.

中文翻译：

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大青山地区晚古元古代地壳演化——来自华北克拉通孔达岩带固阳长胜渠金田埃达克质和A型花岗岩的证据

摘要 与碰撞造山带有关的花岗质岩浆作用为大陆地壳演化提供了重要信息。我们对来自华北克拉通孔达岩带、大青山地区固阳长胜渠金矿区的四个花岗岩样品进行了岩石学、地球化学和锆石 U-Pb-Hf 同位素研究。锆石U-Pb定年结果表明，1950±11 Ma、1935±12 Ma、1846±11 Ma和1812±8.6 Ma的花岗岩类，代表了大青山地区的两次周期性花岗岩岩浆作用。1.95 和 1.93 Ga 花岗岩的 SiO2、K2O 和 Na2O 含量高，Sr/Y 和 (La/Yb)N 比高，但 MgO、Cr 和 Ni 含量低，表明它们是由 a在相对高压的条件下增厚的下地壳。花岗岩显示出负主导的锆石 eHf(t) 值 (-5. 7-1.9)，其锆石 TDM2(Hf) 值在 2.9 和 2.5 Ga 之间，表明一个古老的地壳源，涉及少量的幼年地壳物质。1.85 和 1.81 Ga 石英二长岩的 SiO2、K2O、Na2O、Zr、Nb、Ce 和 Y 含量高，但 MgO、Cr 和 Ni 含量低，Ga/Al 和 FeOt/(FeOt + MgO) 比值高，表明A型花岗岩亲和力。全岩地球化学表明，它们是由TTG和石英闪长岩在高温浅层脱水重熔形成的。石英二长岩的 eHf(t) 值均一 (-10.6–-6.1)，锆石 TDM2(Hf) 值介于 3.0 至 2.8 Ga 之间，表明它们来自新太古代古代地壳。孔达岩带东部1.95-1.93 Ga埃达克质岩浆作用与1.93-1.92 Ga基性岩浆作用和UHT变质作用有关；这表明从碰撞压缩到碰撞后扩展的构造转变。1.85～1.81Ga A型花岗质岩浆作用表明大陆地壳明显减薄和软流圈上涌。这两种不相关的岩浆活动可能分别由孔达岩带和横贯华北造山带的两次碰撞事件诱发。大约在西部和东部块的碰撞。1.85 Ga可能在A型石英二长岩的成因中起重要作用，并影响了孔达岩带大青山地区的地壳演化。这两种不相关的岩浆活动可能分别由孔达岩带和横贯华北造山带的两次碰撞事件诱发。大约在西部和东部块的碰撞。1.85 Ga可能在A型石英二长岩的成因中起重要作用，并影响了孔达岩带大青山地区的地壳演化。这两种不相关的岩浆活动可能分别由孔达岩带和横贯华北造山带的两次碰撞事件诱发。大约在西部和东部块的碰撞。1.85 Ga可能在A型石英二长岩的成因中起重要作用，并影响了孔达岩带大青山地区的地壳演化。