甘肃北山石板井地区花岗岩成因探讨  

The Discussion of the Granite Genesis in Gansu Beishan Shibanjing Area

作　　者：王育习[1] 侯岚[1] 周庆华[1] 全守村[1] 李文明[1] 杨生飞[1] 

机构地区：[1]中国地质调查局西安地质调查中心,陕西西安710054

出　　处：《新疆地质》2014年第3期377-385,共9页Xinjiang Geology

基　　金：中国地质调查局"内蒙古月牙山地区矿产远景调查"项目(1212010981026)资助

摘　　要：甘肃北山石板井地区隶属东天山古陆东延部分的北山中央古陆断隆构造带,由北山岩群构成古老变质结晶基底岩系。该岩群由具有TTG组合或灰色片麻岩和富铝孔兹岩系构成。获得的同位素年龄为(2 757±790)Ma,时代为太古代。侵入其内的中酸性岩获得的同位素年龄分别为(482.3±1.8)Ma^(422±47)Ma和(384.3±2.3)Ma^(332.1±6.8)Ma,分属于加里东期(奥陶—志留纪)和华力西期(晚泥盆—早石炭世)。岩石矿物组合及岩石化学成分揭示,两期岩体岩浆源区与北山岩群有一定相关性。岩石稀土总量较低,与I型花岗岩相似,成因可能为北山岩群的古老变质岩系重熔而形成花岗岩类,为一种后造山岩浆底侵隆升构造环境的产物。Beishah Shibanjing area in Gansu which on the Reishan middle continental tectonic zone of the East extension part of east tianshan mountain ancient land system is the old metamorphic crystalline basement rock series composed by the Northern rock group. The Northern rock group is composed by the TTG group and the AL-rich khondalite series or is composed by the grey gneiss and the Al-rich khondalite series.The isotopic age is （2 757±790） Ma,which belonged to the Archaeozoic era.The isotopic age of some the intermediate-acid rock is from （422±47） Ma to （430±2.5） Ma and the other is from（361.7±6.8） Ma to （332.1±6.8） Ma,the rock is formed in Caledonian period which from Ordoviclan to Silurian and vadscan which from late Devonian to early carboniferous epoch,respectively.It is revealed by the rock mineral and chemical composition that the rock magma source area in both periods is connection with the Northern rock group.TREO for rocks is low, like the I-type granite.The cause of formation probably is the granide remelt with the old metamorphic rock series.The granite is formed in the post-orogenic magma invade lung tectonic environment.

关 键 词：甘肃 北山石板井 中酸性岩 地球化学特征 同位素年龄 成因 

分 类 号：P588.121[天文地球—岩石学]