【作者】 庞振甲；

【导师】 李永军；

【作者基本信息】 长安大学 ， 构造地质学， 2008， 硕士

【摘要】 本文以西准噶尔扎伊尔山一带晚石炭纪阿克巴斯陶花岗岩体为研究对象,从野外产出状态、岩石学特征、岩石组合类型、岩石地球化学特征、构造环境、与成矿的关系等方面,对该岩体作了比较系统的研究,论文摘要如下:1.依据同源岩浆演化序列的观点,依据花岗岩岩石学特征、岩石化学特征、地球化学特征等方面的特征,阿克巴斯陶岩体可划分为一个序列,由早到晚由花岗闪长岩→正长花岗岩→二长花岗岩三个岩石组合类型组成,时代属晚石炭世。2.阿克巴斯陶序列与围岩为侵入接触关系,岩体内部各岩石类型间为脉动接触关系。3.本次工作在该岩体中心的二长花岗岩中采集锆石U-Pb年龄样品一件,根据锆石U-Pb法测定阿克巴斯陶岩体年龄为296Ma,综合分析前人在该岩体中的年龄样品资料,阿克巴斯陶序列成岩时代为晚石炭世。4.阿克巴斯陶序列中SiO2含量为74.51%～78.39%;Al2O3含量为11.8～13.33%;岩石总体偏碱性,Na2O+ K2O为7.87～8.53%,因此,阿克巴斯陶岩体具有高硅、高碱及低铝的显著特征,岩石中未见碱性暗色矿物,长石类矿物以碱性长石为主,暗色矿物以角闪石、黑云母为主,具有A型花岗岩的特征。5.阿克巴斯陶序列K2O、Rb、Th等大离子亲石元素相对富集,岩石中Y/Nb为5.40-8.66,均大于1.2;稀土元素中Eu亏损严重,δEu值为0.038~0.130,总体在0.1左右,稀土配分曲线呈明显的“V”字型,为典型的铝质A型花岗岩。6.阿克巴斯陶序列是在挤压应力下形成于后造山构造环境,它的形成标志着造山作用的结束,应力开始转化为拉张。7.阿克巴斯陶序列碱性花岗岩浆是由上地幔物质(玄武岩浆)作用下源区岩石部分熔融形成的;部分熔融形成的岩浆主要通过压实作用从源区萃取出来,并向达尔布特深大断裂带提供的储集空间运移、聚集;岩浆在形成过程中以分层对流混合的方式发生与壳源物质的混合作用,在岩浆作用过程中斜长石为主要的分离矿物,从而造成了碱性花岗岩明显的Eu负异常;岩浆形成后共有三次较大的分异,由早到晚依次形成了由花岗闪长岩→正长花岗岩→二长花岗岩的演化特征。.8.阿克巴斯陶序列Sn、Pb等元素的背景值高于围岩和地壳的平均值,在花岗岩类岩石化学成分与矿化种类关系图中也显示阿克巴斯陶岩体应与Sn等矿化有关,今后在本区内应重点寻找Sn、Pb等矿产。更多还原

【Abstract】 This dissertation is object on the Akebasitao granite rock of Lower carboniferous in Zhayier mountain area in Xizhungaer, have systemic research to this granite body by field character, petrology, the type of rock association ,lithogeochemistry , tectonic environment and connection with ore-forming et al,the abstract of the dissertation as follows:1.According to the view of comagmatic evolve series,and the character of petrology,petrochemistry,geochemistry et al, Akebasitao granite rock can be plot one series, it be made up of granodiorite,syenogranite and adamellite from early to late , it′s age is Lower carboniferous.2.The contact connection of Akebasitao series and surrounding rock is intrusive contact, the contact connection of every type rock is pulsation.3.We have collected a age sample of Zircon U-Pb in adamellite which located in center of Akebasitao series at this work, it′s age is 296Ma , Akebasitao series age is Lower carboniferous from analyse prevenient date and this date .4.SiO2 is 74.51%～78.39% of Akebasitao series , and Al2O3 is 11.8～13.33% , Na2O+ K2O is 7.87～8.53% , Akebasitao series is alkaline rock。So the character of Akebasitao series is high Si , high alkali and lower Al , the rocks have not alkali dark mineral , majority feldspar mineral are alkali feldspar , majority dark mineral are hornblende and biotite , Akebasitao series have character of A-type granite.5.Akebasitao series enrich big ion lithophile , for example , K2O、Rb、Th et al. Y/Nb is 5.40-8.66,all of them are higher than 1.2 , the Eu of REE element is strongly lack ,δEu is 0.038~0.130 , all of them are about 0.1 , the diagram of REE distriibution patterns is clear“V”type , all of these character as same as typical A-type granite of Al type.6. Akebasitao series be formed at post- orogeny tectonic environment with force of compression.It is a symbol that the orogeny was finish, The stress began translate into tensile.7.Alkali granite magma of Akebasitao series be formed partial melting of original rocks which be effected by upper mantle matter(basaltic magma);the magma which be formed of partial melting be extracted from original source by compaction and migrate to reservoir which be provided by Daerbute deep fracture;the main combination was slice convection combination of crust and mantle at process of magma formed, plagioclase was the main fractional mineral at magmate process ,so the Eu of the alkali granite is clear negativeanomaly ;there are 3 time main differentiation after magma be formed, so produced granodiorite,syenogranite and adamellite from early to late.8.The background value of Sn、Pb et al elements of Akebasitao series is higher than surrounding rocks and average value of crust,the diagram of relationship between the petrochemical of granites and the types of mineralization shows that the Akebasitao series has relationship with Sn mineralization,so we should search for Sn、Pb minerals at native area in the future.更多还原