霍勤知,杨维刚,王海博,李通元,王小成.甘肃金塔县黑石山A型花岗岩锆石U-Pb年龄、地球化学特征及构造意义[J].甘肃地质,2023,(4):1-12
甘肃金塔县黑石山A型花岗岩锆石U-Pb年龄、地球化学特征及构造意义
Zircon U-Pb Age, Geochemical Characteristics and Tectonic Significance of Heishishan A-Type Granite in Jinta County of Gansu Province
  
DOI:
中文关键词:  A型花岗岩  锆石U-Pb年龄  地球化学特征  早泥盆世  甘肃金塔县
英文关键词:A type granite  zircon U-Pb age  geochemical characteristics  Early Devonian Period  Gansu Province
基金项目:甘肃省基础地质调查项目(甘财经二[2018]132号)资助
作者单位
霍勤知 甘肃省地质调查院甘肃 兰州 730000 
杨维刚 甘肃省地质调查院甘肃 兰州 730000 
王海博 甘肃省地质调查院甘肃 兰州 730000 
李通元 甘肃省地质调查院甘肃 兰州 730000 
王小成 甘肃省地质调查院甘肃 兰州 730000 
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中文摘要:
      黑石山序列花岗岩位于甘肃金塔县以北,由粗中粒黑云二长花岗岩、中细粒斑状二长花岗和中细粒正长花岗岩岩类组成,其中,中细粒斑状二长花岗岩和粗中粒黑云二长花岗岩中分获(396. 8 ± 0. 71) Ma、(414. 2 ± 0. 69) Ma的锆石U-Pb年龄,成岩时代为早泥盆世。岩石地球化学显示其为高碱性强过铝质A型花岗岩,微量元素总体富集Rb、Th、Ta、Y,明显亏损Ba、Sr、P、Ti,轻稀土分馏较重稀土略强,具显著负Eu异常,反映岩浆源区斜长石的分离结晶良好。属于陆内壳源花岗岩,构造环境为早泥盆世造山后初始伸展体制下大陆地壳熔融的产物。
英文摘要:
      Heishishan sequence granite is located in the northern margin of Jinta County, Gansu Province. It is composed of coarse-medium-grained biotite monzonitic granite, medium-fine-grained porphyritic monzonitic granite and medium-fine-grained syenogranitestage 3 rocks. The rock geochemistry shows that it is a highly alkaline and strongly peraluminous A type granite. The zircon U-Pb ages of 396. 8 ± 0. 71 Ma and 414. 2 ± 0. 69 Ma were obtained in the medium-fine grained porphyritic monzonitic granite and coarse-medium grained biotite monzonitic granite. The rocks are rich in Rb, Th, Ta and Y, and obviously depleted in Ba, Sr, P and Ti. The fractionation of light rare earth is slightly stronger than that of heavy rare earth, with significant negative Eu anomaly, reflecting the good separation and crystallization of plagioclase in the magma source area. It belongs to the nature of continental crust source granite rock, and the tectonic environment is the product of continental crust melting under the initial extensional system after Early Devonian orogeny.
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