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尼古拉群镁铁质熔岩可分成三类不同的岩相及地球化学类型:第Ⅰ类熔岩为辉石-斑状苦橄岩、玄武岩及安山岩,属于高钾质-橄榄安粗质岩石系列;第Ⅱ类熔岩主要为辉石-斜长石-斑状玄武岩、安山岩,属于低钾质钙碱系列;第Ⅲ类熔岩为玄武岩(拉斑玄武岩-过渡型玄武岩)和安山岩。第Ⅰ类和第Ⅱ类熔岩具有低含量的Ti、Zr、Y、Nb和中—高含量的K、Rb、Ba及Sr,明显地表现为一与消减作用有关的火山喷发构造背景。第Ⅲ类熔岩的化学特征介于现代岛弧与板内火
The Nikolae Group mafic lava can be divided into three types of lithofacies and geochemical types: the lavas of type I are pyroxene-porphyrite, basalt and andesite, belonging to the series of high-kalium-olivan coarsening rocks; The lavas of Group II are mainly pyroxene-plagioclase-porphyritic basalt and andesite, belonging to the low-kalium calc-alkaline series. The lavas of type III are basalts (tholeiite-transitional basalts) and andesite. The lavas of Group I and II have low contents of Ti, Zr, Y, Nb and medium-high contents of K, Rb, Ba and Sr, clearly showing a volcanic eruption tectonic setting related to depletion. The chemical characteristics of the third type of lava are between modern island arc and intraplate fire