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对卡拉岗组火山岩岩石化学特征分析和研究结果表明 ,火山岩碱性程度为碱性 -钙碱性 ,岩石系列为高铝玄武岩系列、拉斑玄武岩系列及碱性玄武岩系列 ,求得钙碱指数为 5 2 ,属张性环境 ,在全碱—二氧化硅图上样品落入玄武岩区及流纹岩区 ,分异指数频率曲线表明具有大陆拉张的双峰式特点 ,认为该区下二叠统卡拉岗组火山岩产于双峰式大陆拉张构造环境
The petrochemical characteristics of volcanic rocks in the Kararagang Formation and the results show that the alkaline degree of volcanic rocks is alkaline-calc-alkaline, and the series of rocks are high-alumina basalt series, tholeiite basalt series and basic basalt series. The calc-alkaline index is 5.2 In a tensioned environment, the sample falls into basalt and rhyolite on the all-alkali-silica map. The frequency curve of the divergence index shows the bimodal characteristics of continent stretching. Volcanic rocks of the Tongkalagang Formation are developed in the Bengtang-China continent