阿尔泰蒙其克晚石炭世闪长岩体矿物学特征及地质意义  

Mineralogical Characteristics of Late Carboniferous Diorite and Its Geological Significance in the Monqik District,Altay

作　　者：屈李华 蒋忠祥[1] 赵芳 周晓颖 孟盛向 赵同寿 伊永国[1] 侯明利 Qu Lihua;Jiang Zhongxiang;Zhao Fang;Zhou Xiaoying;Meng shengxiang;Zhao Tongshou;Yi Yongguo;Hou Mingli(Geophysical and Geochemical prospecting group of Xinjiang bureau of geology and mineral resources Exploration and Development,Changji,Xinjiang,831100,China)

机构地区：[1]新疆维吾尔自治区地质矿产勘查开发局地球物理化学探矿大队,新疆昌吉831100

出　　处：《新疆地质》2022年第3期339-350,共12页Xinjiang Geology

基　　金：新疆地质勘查基金项目新疆青河县二台-阿拉塔斯一带1:5万综合物探普查(A17-1-XJ04)资助。

摘　　要：蒙其克晚石炭世岩体位于玛因鄂博断裂带南缘。本文以蒙其克晚石炭世闪长岩中的角闪石为研究对象,在岩相学观察基础上,对岩体中的角闪石进行电子探针成分分析,厘定岩体结晶温压、氧逸度和含水量等物理化学条件,探讨岩浆演化及成岩过程。结果显示,岩体角闪石具富镁(10.39%~14.32%)、富钙(11.27%~11.96%)、贫钾(0.44%~1.15%)及富钠(Na_(2)O/K_(2)O>1.0)特征,属于镁角闪石、浅闪石、浅闪石质普通角闪石。据矿物电子探针成分及化学式计算得出岩体中角闪石结晶温度为762.03℃~865.12℃;成岩压力为82.37~221.48 MPa;侵位深度为3.11~8.37 km;剥蚀速度为9.9~26.7 m/Ma;氧逸度在△NNO+0.12到△NNO+1.56之间;logfO_(2)为-13.54~-12.12;结晶时熔体中含水量为4.26%~5.90%。角闪石为岩浆成因,部分发生蚀变,形成过程中具幔源物质的混染且与俯冲作用有关。The late Carboniferous plutons in the Monqik are located at the southern edge of the Mainebo fault zone.This study focuses on the hornblendes from diorites in the Monqik.According to the detailed petrographic observations,the authors analyzed the composition of the hornblendes from diorites by the electron microprobe analysis(EPMA).Physicochemical conditions such as crystallization temperature and pressure,oxygen fugacity and water content are determined,and the magmatic evolution and diagenetic process are discussed.The results show that the rock mass hornblende is rich in magnesium(10.39%~14.32%),rich in calcium(11.27%~11.96%),poor in potassium(0.44%~1.15%)and rich in sodium(Na_(2)O/K_(2)O>1.0).It belongs to magnesium amphibole,light amphibole and light hornblende common amphibole.Results calculated from chemical composition by mineral electron probe show that the crystallization temperature of hornblende in the Mongqik rock body is between 762.03℃~865.12℃,and diagenetic pressure is between 82.37~221.48Mpa,and emplacement depth is between 3.11~8.37km,and erosion rate is between 9.9~26.7m/Ma,and oxygen fugacity is△NNO+0.12 to△NNO+1.56,and logfO_(2) is between-13.54 to-12.12,and the water content of melt is 4.26%to 5.90%.hornblende is of magmatic origin and partially altered.During its formation,it was contaminated by mantle derived materials and related to subduction.

关 键 词：角闪石 矿物学特征 物理化学条件 蒙其克岩体 阿尔泰 

分 类 号：P534.45[天文地球—古生物学与地层学] P57[天文地球—地质学]