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东太平洋海隆洋脊玄武岩具有不同的类型。对1.23°N(EPR(A))、3.10°S(EPR(B))和5.70°S(EPR(C))3区域洋脊玄武岩元素地球化学分析发现,EPR(A)附近样品属于富集型玄武岩,其他2个区样品基本属于亏损型玄武岩。EPR(A)区附近洋脊玄武岩具有斜长石含量高、自形程度好、粒径大、高Al2O3、低TFeO和低MgO等特征;EPR(B)和EPR(C)区玄武岩整体上为亏损型,具有斜长石含量低、粒径小、高TFeO、高MgO等特征。EPR(A)区岩浆来源较浅,且在浅部岩浆房内经历了较为强烈的岩浆混合-结晶作用,其混合作用有3个阶段。同时该区产生斜长石斑晶的堆积作用,喷出岩浆具有高黏度、低密度特征。与之相比,其他2个区域岩浆来源可能较深,并且所经历的低压岩浆混合作用期次可能较少。从岩相学及Sr和Eu元素含量特征来看,岩浆演化过程中经历了单斜辉石的高压分离作用,而斜长石在这一过程中很可能没有经历分离作用。
Eastern Pacific Hilo ridge basalts have different types. Elemental geochemical analyzes of basalts in the ridges of 1.23 ° N (EPR (A)), 3.10 ° S (EPR (B)) and 5.70 ° S (EPR (C)) found that samples near EPR (A) Type basalt, the other two samples are basically loss-type basalt. The ridge basalts near EPR (A) have the characteristics of high plagioclase content, good self-shape, large grain size, high Al2O3, low TFeO and low MgO. The basalts in EPR (B) and EPR Loss type, with low content of plagioclase, small particle size, high TFeO, high MgO and other characteristics. The magma source in the EPR (A) area is shallower and has a stronger magma mixing-crystallization in the shallow magma chamber. The mixing has three stages. At the same time, the area has plagioclase plagioclase deposition, the magma has high viscosity and low density. In contrast, the other two regions may have a deeper source of magma and may experience less periods of low-pressure magmatic mixing. From the lithofacies and the Sr and Eu elemental content, the magmatic evolution experienced high pressure separation of clinopyroxenes, and plagioclase probably did not undergo the separation in this process.