云南澜沧老厂矿区火山岩岩石化学特征及构造背景

Rock Chemical Characteristics and Tectonic Background of Volcanic Rock in Yunnan Lancang Laochang Mining Area

通过对老厂矿区依柳组火山岩中各旋回岩石化学特征分析,确定了老厂火山岩以基性岩为主,岩性由中基性向基性演化,岩石系列由拉斑玄武岩系列向碱性系列转化;主量元素特征显示,老厂火山岩K、Ti含量高;稀土元素含量较高,轻稀土元素从不富集到富集均有分布,总体呈现出轻稀土微富集,球粒陨石标准化稀土元素配分图显示老厂火山岩与典型大陆裂谷拉斑玄武岩和大陆裂谷碱性玄武配分模式相当,表明老厂火山岩形成于大陆裂谷环境。

According to the analysis of chemical characteristics of each cycle rock in Laochang mining area Yiliu group volcanic rock , basic rock is main part of Laochang volcanic rock is confirmed, evolvement of lithology is from intermediate-basic rock to basic rock, transform of rock series is from tholeiite series to alkaline series; Characteristics of major element showing the K, Ti content are high in Laochang volcanic rock ; Rare earth elements content is high, LREE distribution is from un-enrichment to enrichment, LREE is slightly enrichment generally, Laochang volcanic rock has similar distributed pattern with typical mainland rift tholeiite mainland rift alkali basalt showed by chondrite standardization ree partition graph, generally showed that Laochang volcanic rock was formed in continental rift.