地质论评2012，Vol.58Issue(4)：653-659,7.
一种改进的简单的估算原始岩浆的方法——以峨眉山大火成岩省丽江苦橄岩为例
An Improved Simple Method for Estimating Primitive Magma——a Case for the Picrites in the Lijiang Area of Emeishan Large Igneous Province
摘要
Abstract
Based on Fe-Mg distribution coefficient between olivine and melt, the MgO-FeO evolution diagram is built. The compositions of primary magmas can be estimated by the intersection point of straight line and curve which illustrates liquids in equilibrium with olivine. It is suitable for the system of olivine fractional crystallization, and its advantage is that it can be easily and visually used. It is also pointed out how the diagram is applied. To show how to recover the composition of primitive magma and to explain the petrogenesis, the samples from the Lijiang area of Emeishan large igneous province are taken for examples. Results show that composition for the MgO and FeO contents of Shiman primitive magma are 23. 5% and 12. 8% respectively, with larger melting fraction. Samples SM-14 and SM-15 are resulted from low olivine fractional crystallization, so their contents could approximately represent primitive magma of Shiman area. Daju primitive magma may be divided two types. One has 19. 8% MgO and 11. 3% FeO contents, with lower melting fraction. The other one has 23% MgO and 13. 3% FeO contents similar to the Shiman, with larger melting fraction. Samples from the Daju all experienced large olivine fractional crystallization. Most basalts from the Emeishan large igneous province have MgO contents less than 8% , and include many clinopyroxene and plagioclase phenocrysts,, suggesting that these basalts can not be directly resulted from olivine fractional crystallization of Emeishan primitive magma.关键词
原始岩浆/分配系数/质量平衡/峨眉山大火成岩省Key words
primitive magma/ distribution coefficient/ mass balance/ Emeishan large igneous province引用本文复制引用
李永生,张招崇,聂保锋..一种改进的简单的估算原始岩浆的方法——以峨眉山大火成岩省丽江苦橄岩为例[J].地质论评,2012,58(4):653-659,7.基金项目
本文为国家自然科学基金资助项目(编号40925006)、国家973项目(编号2009CB421002)和111计划(编号B07011)的成果. （编号40925006）
