华北陆块南缘老牛山杂岩体岩石成因:来自黑云母的信息  

Petrogenesis of Laoniushan Granitoid Complex in the Southern Margin of North China Block:Information from Biotite

作　　者：齐秋菊[1] 王晓霞[2] 柯昌辉[2] 李金宝[3] QI Qiu-ju 1, WANG Xiao-xia 2, KE Chang-hui 2, LI Jin-bao 3(1. Institute of Resource Survey and Assessment, East China Mineral Exploration and Development Bureau forNon-ferrous Metals, Nanjing 210007, Jiangsu, China; 2. MLR Key Laboratory of Metallogeny and MineralAssessment, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;3. School of Earth Science and Resources, Chang an University, Xi an 710054, Shaanxi, Chin)

机构地区：[1]江苏省有色金属华东地质勘查局资源调查与评价研究院,江苏南京210007 [2]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,北京100037 [3]长安大学地球科学与资源学院,陕西西安710054

出　　处：《地球科学与环境学报》2018年第3期252-261,共10页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(41572052)

摘　　要：老牛山杂岩体位于华北陆块南缘,由晚三叠世(印支期)和晚侏罗世(燕山期)花岗岩组成。在野外地质和岩相学观察的基础上,对老牛山杂岩体中的黑云母进行系统的化学成分研究。结果表明:不同时期不同岩性的黑云母成分变化不大,具有富Mg、Ti、Al、K的特征;黑云母主要是镁质黑云母;自印支期到燕山期黑云母的成分具有一定的变化规律,主要表现为TiO2、FeOT和Al2O3含量有所升高,而MgO含量逐渐降低;印支期花岗岩中黑云母结晶温度在600℃~700℃之间,结晶压力为0.98~1.95kbar,相应的侵位深度为3.72~7.38km;燕山期花岗岩中黑云母结晶温度在650℃~700℃之间,结晶压力为1.47~2.01kbar,相应的侵位深度为5.55~7.61km;老牛山杂岩体属于同熔型(I型)花岗岩,具有壳幔混源成因的特征,但花岗岩类成岩物质来源略有不同,印支期花岗岩较燕山期花岗岩的源区物质组成,可能幔源物质更多一些。Laoniushan granitoid complex is located in the southern margin of North China Block,and consists of Late Triassic（Indosinian）and Late Jurassic（Yanshanian）granitoids.Based on the field geological and petrographic observation,the systematic chemical compositions of biotites were carried out.The results show that the compositions of biotites have a little change with high Mg,Ti,Al and K contents;these biotites are mainly Mg-biotites;the compositions of biotitesfor granitoids have certain change rule from Indosinian to Yanshanian,and mainly the contents of TiO2,FeOT and Al2O3 increase,and the contents of MgO gradually decrease;biotites from Indosinian granites crystallize under temperature of 600 ℃-700 ℃,and pressure of 0.98-1.95 kbar,and the corresponding emplacement depth is 3.72-7.38 km;biotites from Yanshanian granitoids crystallize under temperature of 650 ℃-700 ℃,and pressure of 1.47-2.01 kbar,and the corresponding emplacement depth is 5.55-7.61 km;Laoniushan granitoid complex belongs to syntexis type（I-type）granitoid,and derives from a crust-mantle mixing source,while the diagenetic material sources of Indosinian and Yanshanian granitoids are slightly different,manifested as the mantle source material could be more in Indosinian granitoids.

关 键 词：杂岩体 黑云母 结晶温度 结晶压力 侵位深度 同熔型花岗岩 壳幔混源 华北陆块 

分 类 号：P575.1[天文地球—矿物学] P578.959[天文地球—地质学]