内蒙古苏莫查干地区燕山期过铝质花岗岩研究  

Yanshanian peraluminous granite in Sumochagan area,Inner Mongolia

作　　者：许东青[1] 聂凤军[1] 江思宏[1] 张万益[1] 钱明平 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037 [2]河南省灵宝市金源矿业有限责任公司,河南灵宝472500

出　　处：《岩石矿物学杂志》2008年第2期89-100,共12页Acta Petrologica et Mineralogica

基　　金：国家自然科学基金资助项目(40573025)

摘　　要：内蒙古苏莫查干地区的燕山期花岗岩体夹持于二连浩特-贺根山和索伦山-西拉木伦河深大断裂之间,其代表性岩石样品以富K、Al、Rb、Th和轻稀土元素,亏损Sr、Ti、P和Eu为特点,属高钾钙碱性过铝质花岗岩。钕同位素研究表明,岩石全岩样品的εNd(t)变化范围为0.77^-4.65,t2DM变化范围为869~1310Ma(多集中于1072~1310Ma),与兴蒙造山带中的微陆块花岗岩相似。铅同位素的206Pb/204Pb=18.114~19.150,平均18.658;207Pb/204Pb=15.517~15.598,平均15.556;208Pb/204Pb=38.384~39.054,平均38.614;μ=9.2~9.5,平均9.37。所有数据点均投绘在造山带与地幔Pb演化线之间。主元素、微量元素、钕和铅同位素数据表明,本区燕山期花岗岩可能是在华北板块和西伯利亚板块碰撞造山后的伸展构造环境中,壳幔源物质通过物理混合后,再次发生重熔、成浆和结晶分异作用的产物,并且与该区的萤石和贱金属成矿作用具有密切的时空和成因联系。The Yanshanian granite in the Sumochagan area, emplaced between Erlianhaote-Hegenshan and Suo-lunshan-Xilamulun River deep-rooted faults, is rich in K, Al, Rb, Th and LREE, and depleted in Sr, Ti, P and Eu, belonging to the high-K calci-alkaline peraluminous granite, εNd（ t ） ranges from 0.77 to - 4.65, t2DM ranges from 869 to 1 310 Ma, which is similar to things of the granite of ancient microplate in the Hingganling- Mongolian orogenic belt. The μ values of Pb isotope range from 9.2 to 9.5, with an average of 9.37. The ratios of 206pb/204pb range from 18. 114 to 19.150, with an average of 18.658, those of 207pb/^204Pb range from 15. 517 to 15. 598, with an average of 15. 556, those of 208pb/204pb range from 38. 384 to 39. 054, with an average of 38. 614. All these data are plotted in the area between the mantle and the orogenic belt. Geochemical characteristics of the Yanshanian granite formed in a post-collision extensional tectonic environment indicates that the Yanshanian granite is a product of the mixture of the crust and the mantle substance. The Yanshanian granite is very closely related to fluorite and base metal mineralization in the Sumochagan area.

关 键 词：过铝质花岗岩 元素地球化学 钕-铅同位素 成岩作用 苏莫查干地区 内蒙古 

分 类 号：P588.121[天文地球—岩石学]