黑龙江二克山与五大连池富钾火山岩特征及成因

二克山与五大连池火山岩为一套基性、酸性程度偏高、强碱性系列的富钾白榴橄榄玄武岩和白榴玄武岩组合。岩石成分，随ＳｉＯ２含量增加，Ａｌ２Ｏ３，Ｋ２Ｏ，Ｎａ２Ｏ增加，ＭｇＯ，ＣａＯ，ＦｅＯ降低。微量元素具有不相容元素强烈富集，相容元素较高的特征。地球化学特征表明，本区地幔曾受过部分熔融，导致地幔的亏损，尔后地幔又受到上升流体交代作用。地壳的同化混染，只能降低原生岩浆的基性度，不能使其富钾，表明源区可能存在着金云母熔融，在部分熔融程度较低条件下，形成原始富钾岩浆。

CHARACTERASTICS AND GENESIS OF RICH-KVOLCANIC ROCKS FROM ERKESHAN ANDWUDALIANCHI, HEILONGJIANG

The Erkeshan and Wudalianchi volcano groups occur in an intersection position ofShongliao Basin and Xiaoxinganling uplift.Their rock assemblage is luicite olivine basalt andluicite basalt,The vary trend of the peterochemistry is as follows:content of Al2O3,K2O andNa2O increase with SiO2.In the trace element,the incompatible elements are highly rich,whilecontent of the compatible elements are high.The geochemical characteristics show that uppermantle in this region has undergone partial melting.This action lead to mantle depletion,meanwhile fusible components,incompatible elements,transitional metal elementS and REEdecrease.After that,the mantle also has undergone metasomatism by upwelling fluid.The assimilation and contamination of the crust only decrease the basicity of primary magma,can notenrich in K2O.It shows there is melting process of philogopite in the source region.The K-richmagma is formed by partial melting.