得荣县奔都乡奔都村一带三叠系上统哈工组火山岩岩石地球化学特征

Geochemical Characteristics of Upper Triassic Hagong Formation Volcanic Rocks in Bendu Village,Bendu Township,Derong County

得荣县奔都乡奔都村一带上三叠统哈工组内火山岩主要由玄武岩、玄武质火山角岩、玄武-安山质火山角砾岩等构成。火山岩岩石学、元素地球化学特征分析表明,火山岩属于碱性系列;微量元素显示大离子亲石元素相对富集,高场强元素相对亏损;稀土总量较高,轻稀土富集,重稀土亏损,具Eu正异常。综合研究认为,哈工组火山岩形成于大陆板内拉张构造环境。

The volcanic rocks in the Upper Triassic Haong Formation in Bendu Village,Bendu Township,Derong County are mainly composed of basalt,basaltic hornfels and basalt-Andesitic volcanic breccia.The analysis of petrological and geochemical characteristics of volcanic rocks shows that volcanic rocks belong to alkaline series.The trace elements showed the relative enriched of large ion lithophile elements and the relatively depleted of high field strength elements.The total amount of rare earth is high,the light rare earth is enriched,and the heavy rare earth is depleted,with positive Eu anomaly.Comprehensive research shows that the volcanic rocks of the Hagong Formation were formed in the intra-continental plate tension tectonic environment.