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.
出处
《吉林大学学报(地球科学版)》
EI
CAS
CSCD
北大核心
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)
关键词
流纹岩
地球化学
早白垩世
地壳熔融
大兴安岭北部
rhyolites
geochemistry
Early Cretaceous
crustal melting
north Daxing'anling