大兴安岭北部早白垩世上库力组流纹岩的地球化学特征及成因  

Geochemical Characteristics and Tectonic Setting of Rhyolites of the Early Cretaceous Shangkuli Formation,North Daxing'anling

作　　者：尹志刚[1] 张跃龙 杜玉春[1] 

机构地区：[1]辽宁工程技术大学矿业学院,辽宁阜新123000 [2]黑龙江省地质调查研究总院齐齐哈尔分院,黑龙江齐齐哈尔161005

出　　处：《吉林大学学报（地球科学版）》2013年第3期788-796,共9页Journal of Jilin University：Earth Science Edition

基　　金：国家自然科学基金项目(40972041)

摘　　要：大兴安岭北部早白垩世上库力组流纹岩具有富碱(w(K2O+Na2O)>6.10%)、高w(K2O)(3.25%～5.30%)、高K2O/Na2O(0.67～2.48)的特点,属于高钾钙碱性系列。强烈富集大离子亲石元素(LILE)和轻稀土元素(LREE),明显亏损Ba、Sr、Nb、P、Ti,较高的Th质量分数和高的Rb/Ba、Rb/Sr和Zr/Ba表明,该流纹岩形成于大陆板内拉张构造环境,是蒙古-鄂霍茨克造山带形成后伸展作用的结果。现有资料表明,形成流纹岩的原生岩浆可能是下地壳部分熔融的产物。The rhyolites of the Early Cretaceous Shangkuli Formation in northern Daxing＇anling belong to high-K calc-alkaline volcanic rock series characterized by rich-alkaline（K2O＋Na2O6.10%）,high K2O（3.25%-5.30%） and high ratios of K2O/Na2O（0.67-2.48）.These samples show strong enrichment in large ion lithophile elements（LILE） and in light rare earth elements（LREE）.But the elements of Ba,Sr,Nb,P,and Ti are apparently depleted.The higher Th content and high Rb/Ba,Rb/Sr and Zr/Ba ratios of the rhyolites suggested a continental intraplate rifted setting related to the extension stage after the formation of Mongolia-Okhotsk orogenic belt.The current data indicate that the parental magma for rhyolites could be the products of the lower crust partial melting.

关 键 词：流纹岩 地球化学 早白垩世 地壳熔融 大兴安岭北部 

分 类 号：P59[天文地球—地球化学]