摘要
内蒙古新胜屯地区花岗岩侵入晚侏罗世玛尼吐组及白音高老组火山岩的岩性主要为中粒花岗岩、花岗斑岩及钾长花岗斑岩。在野外地质调查的基础上,通过研究晚侏罗世花岗岩的产出特征、岩石学特征及岩石地球化学特征,发现新胜屯地区花岗岩具有高硅碱富钾和贫镁低钙、TFeO/MgO比值高、碱性及准铝质—过铝质的特征;稀土元素总量高,轻稀土富集,Eu亏损显著,稀土元素配分曲线呈不对称右倾的"海鸥型"展布;微量元素Zr、Y、Ce及高场强元素Rb、Th、K、Sm、Nd含量高,而Sr、Ba、P、Ti亏损。上述岩体地球化学特征表明岩体属铝质A型花岗岩,形成于非造山期板内拉张的构造环境。
In the Xinshengtun area of Inner Mongolia,the granite intruded volcanic rocks of the Late Jurassic Manitu Formation and Baiyin＇gaolao Formation,whose lithology is mainly medium-grained granite,granitic porphyry and K-feldspar granite porphyry. Based on field geological investigation,this work studied the occurrence,petrology features and petrochemical data of the Late Jurassic granite. It is found that the granite in the Xinshengtun area is high in silicon and alkali,rich in potassium,poor in magnesium and calcium,with high ratio of TFeO / MgO,and is alkaline and mtaluminous-peraluminous. The total amount of rare earth elements is great,with enrichment of light rare earth and significant loss of Eu. The REE distribution patterns show an asymmetrical right-dipping seagull type distribution. It is rich in field strength elements of Zr,Y and Ce,and high in Rb,Th,K,Sm and Nd,while Sr,Ba,P and Ti elements are depleted. The above petrogeochemical characteristics indicate that the rock mass is aluminous A-type granite,formed in a extensional tectonic setting within non-orogenic plate.
出处
《地质学刊》
CAS
2016年第2期197-204,共8页
Journal of Geology
基金
内蒙古自治区地质勘查基金项目"内蒙古兴安盟中心屯等四幅1:5万区域矿产地质调查"(NMKD 2006-06)
关键词
铝质A型花岗岩
非造山期拉张构造环境
晚侏罗世
内蒙古新胜屯
aluminous A-type granite
non-orogenic
extensional tectonic setting
Late Jurassic
Xinshengtun area in Inner Mongolia
