内蒙古乌兰德勒钼铜多金属矿区花岗岩类岩体时空演化

发布时间：2018-03-31 21:01

本文选题：花岗岩类　切入点：乌兰德勒　出处：《中国地质大学(北京)》2015年硕士论文

【摘要】：乌兰德勒钼铜多金属矿区,花岗类岩石组构反映了岩浆母体冷却的过程。结合岩相学、岩体年代学和地球化学数据,就可以提供岩浆演化过程中的物理—化学信息。将花岗类岩石分为四大类,即黑云母二长花岗岩、中细粒花岗岩、花岗闪长岩和花岗斑岩,通过对研究区岩石组构和化学分析以及zk903钻孔空间次序整合认定黑云母二长花岗岩和闪长岩为早期岩体,后期的细粒花岗岩侵入老岩体中,形成了花岗斑岩、花岗闪长岩等高分异类型的岩石。根据127组文献锆石年龄统计,花岗类岩体的年龄主要集中在135-145Ma、160-165Ma(早燕山期)、290-320Ma和345-360Ma(海西期)。早燕山期花岗岩锆石形态完整,色泽较浅,而海西期花岗岩锆石形态残缺,色泽发黑,多出现核部老、边部新的锆石。花岗类岩石Si O2含量为59%-79%,K2O+Na2O含量为3%-9%,Al2O3含量为9%-17%。Si O2与P2O5、K2O、Al2O3、Ti O2、Ca O、Mn O、Na2O、Mg O呈线性关系,呈现出典型的结晶分异的演化趋势,岩石表现出过铝高钙的特征,为I-A型。稀土元素配分图为右倾式,出现铕(Eu)的负异常。花岗斑岩和花岗闪长岩较黑云母二长花岗岩和中细粒花岗岩出现了稀土亏损,说明了斜长石和石英等浅色矿物大量的出溶分离—重结晶。古生代花岗岩地块受到区域走滑应力的影响,长期受到拉张力作用,形成了方块式的构造样式,正是这样的构造控制了燕山期岩体的侵入方式,造成了花岗质岩浆对老岩体进行了充分的混染以及热液对成矿元素的充分萃取。辉钼矿成矿年龄和Re含量对物质来源的判定均与燕山期岩浆的混染和热液作用密切相关。岩体空间演化关系和岩石地球化学数据综合分析对岩浆系统的物理—化学过程和岩石成因都有相对综合性的深刻认识。
[Abstract]:The granitic rock fabric reflects the cooling process of the magmatic parent body in Wu Lan's molybdenum copper polymetallic ore area, combining with petrographic, geochronological and geochemical data. The granitic rocks can be divided into four types: biotite monzogranite, mesomorphic granite, granodiorite, granodiorite and granitic porphyry. Based on the analysis of rock fabric and chemistry in the study area and the spatial sequence integration of zk903 borehole, it is concluded that biotite monzogranite and diorite were early rock mass, and granitic porphyry was formed after fine-grained granite intruded into the old rock mass. According to the age statistics of 127 groups of zircon, the ages of granitic rocks are mainly 135-145Ma-160-165Ma (early Yanshanian 290-320Ma and 345-360Ma) (Hercynian). The zircons of early Yanshanian granites are of complete morphology and light color. The zircon morphology of Hercynian granite is incomplete, the color is black, the core is old and the edge is new. The Sio _ 2 content of granitic rocks is 59-79 and the content of K _ 2O Na2O is 3-9O / Al _ 2O _ 3. There is a linear relationship between the content of 9%-17%.Si _ 2O _ 2 and the content of P _ 2O _ 5-K _ 2O-Al _ 2O _ 3-Al _ 2O _ 3O _ 2SiO _ 2CaO _ 2mn _ 2O _ O _ 2O _ (Na _ 2O _ O _ 2O _ O). There is a typical evolution trend of crystallization differentiation. The rock shows the characteristics of peraluminous and high calcium, which is I-A type. The REE partition pattern is right-dip. There are negative anomalies of europium EU). Granitic porphyry and granodiorite show REE depletion compared with biotite monzomorphic granite and medium-fine-grained granite. This shows that a large number of light-colored minerals, such as plagioclase and quartz, are exsolution separated and recrystallized. The Paleozoic granite block was affected by the regional strike-slip stress and subjected to tensile tension for a long time, forming a block tectonic style. It is this kind of structure that controls the intrusive mode of the Yanshanian rock mass. The results show that granitic magma makes sufficient mixing of old rock mass and sufficient extraction of ore-forming elements by hydrothermal solution. The determination of metallogenic age and re content of molybdenum ore on material source is closely related to the mixing of Yanshanian magma and hydrothermal action. The spatial evolution relationship of rock mass and the comprehensive analysis of petrogeochemical data have a relatively comprehensive and profound understanding of the physico-chemical process and petrogenesis of magmatic system.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.2;P588.121

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