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三塘湖地区早石炭世火山活动强烈，发育以安山岩类为主的玄武岩、安山岩、英安流纹岩的岩石组合。玄武岩类具有Ａｌ２Ｏ３含量高，铁含量低，ＴｉＯ２含量低，大离子亲石元素及轻稀土元素富集的钙碱性系列特点。微量元素比值蛛网图和稀土元素配分型式具有岛弧钙碱性玄武岩的特征。利用不同构造环境玄武岩的ＮｂＺｒＹ图式、ＣｒＣｅ／Ｙ图式判别出三塘湖地区在早石炭世为岛弧构造环境。
The volcanic activity of Early Carboniferous in the Santanghu area is intense, and the rock assemblage of basalts, andesites and lianan rhyolites mainly composed of andesite is developed. Basalt has the characteristics of high content of Al2O3, low iron content, low TiO2 content, large ion lithophile elements and light rare earth elements enrichment of calcium alkaline series. The ratio of trace elements to cobweb and REE patterns have the characteristics of island-arc calc-alkaline basalts. Based on the NbZrY diagram and CrCe / Y diagram of basalts in different tectonic setting, the Santanghu Lake area was identified as an island arc tectonic setting in the Early Carboniferous.