安徽黄山花岗岩岩石学、矿物学及地球化学研究  

The petrology,mineralogy and geochemistry study of the Huangshan granite intrusion in Anhui Province.

作　　者：张舒[1] 张招崇[1] 艾羽[1] 袁万明[1] 马乐天[1] 

机构地区：[1]中国地质大学,地质过程与矿产资源国家重点实验室,北京100083

出　　处：《岩石学报》2009年第1期25-38,共14页Acta Petrologica Sinica

基　　金：教育部新世纪人才支持计划(NCET-04-0728);黄山管委会资助项目

摘　　要：安徽黄山复式岩体位于扬子板块东南缘,江南陆内造山带内。黄山复式岩体由太平花岗闪长岩岩体和黄山花岗岩岩体组成。根据岩体的接触关系和各期次岩石的矿物学及岩石学特征,可以将黄山花岗岩岩体分为4个期次:第一期为中粒二长花岗岩;第二期为粗粒似斑状花岗岩;第三期为中细粒斑状花岗岩;第四期为粗粒含斑花岗岩。从矿物的组成上来看,各期次的岩石均为广义的花岗岩类,主要矿物以石英和长石为主,太平岩体和黄山岩体中的斜长石均表现出钠长石的特点,同时黄山岩体特征的出现条纹长石。各期次岩体均含有少量的铁白云母,显示出过铝质的特点。各期次岩石总体具有高硅(SiO_2含量大于75%)、高碱(ALK含量大于7.9%)、低钙(CaO含量小于1%)及高FeO^T/MgO比值(13～37)的特点。同时岩石强烈富集稀土元素(除Eu出现明显的负异常)、Zr、Hf、Nb等高场强元素,贫Ba、Sr、Ni,高10000×Ga//Al(比值大于2.6),这些特征均指示黄山复式岩体具有A型花岗岩的特点。通过Eby的判别图解将其进一步划分为A2型花岗岩,代表其形成于拉张的构造背景之下。结合Sm-Nd同位素特征(ε_(Nd)(t)=-4.2～-5.6),确定黄山复式岩体的源区物质可能为一套元古宙的火山岩。同时稀土模拟结果表明,黄山岩体的原始岩浆是这种源区大约20%部分熔融的产物。岩体形成于斜向俯冲引发的陆内剪张环境内。The Huangshan granite intrusion situated in Anhui Province, southeast of China, is located at the southeastern boundary of Yangtze plate. The Huangshan granite intrusion consists of Taiping granodiorite and Huangshan granite. Based on the contact relationship, the Huangshan granite (can lie divided into four stages (from early to late) : medium-grained monzogranite, coarse-grained porphyric granite, fine-medium grained porphyric granite, fine-coarse grained granite. All stages of the granitoids have similar mineralogical components which are composed of Fe-muscovite, K-feldspar, albite and (quartz. The presence of Fe-muscovite indicates that the Huangshan granite intrusion is peraluminous. The granitoids are characterized by high SiO(2)(>75%), alkali (7. 9% 8.6%), low CaO (<1%) and high FeO(T)/MgO (13 similar to 37). The granitoids also have relatively high BEE content ( except for Eu) high strength field elements such as Zr,Hf,Nb,low Ba,Sr,Ni, and high 10000 x Ga/Al (>2.6), indicating A-type granitoids, On the base of the classification diagrams proposed by Eby, the Huangshan granitoids can be classified into A2, which is usually believed to be formed under an extensional tectonic setting. Their Nd isotopic compositions suggest that the primary magmas of the Huangshan intrusion are derived from the Proterozoic andesitic rocks in the region, and the REE model also supports the conclusion. The late Mesozoic Huangshan intrusion can provide some important petrologic constrains on the transitional tectonic in Southeastern China.

关 键 词：A型花岗岩 晚中生代 部分熔融 黄山花岗岩体 中国东南部 

分 类 号：P588.121[天文地球—岩石学]