摘要
大火成岩省(LIPs)是发生在板块内部的超大规模岩浆活动的产物,其成因一直是地学界研究的前沿和热点。影响LIPs形成的主要因素包括温度、压力、源岩性质和源区水含量,虽然已积累较多的成果,但对于地幔源区中的水是否影响及如何影响LIPs的形成,目前还知之甚少。本文回顾了已有的实测LIPS水含量研究工作,并介绍了一种新的分析手段,即利用傅里叶变换红外光谱(FTIR)测定早期结晶的单斜辉石斑晶水含量,然后结合水在单斜辉石斑晶和熔体间的分配系数来反演得到LIPs的"原始"水含量。通过塔里木和峨眉山两个大火成岩省的研究实例,综合评价了温度、压力、源岩性质和水含量这4个因素的影响,指出很可能只有当这些因素同时具备了才能产生LIPs。
Large igneous provinces(LIPs) are products of the ultra-large-scale intraplate magmatism. The genesis of LIPs has always been the frontier and hot-spot in geoscience community. Theoretically, temperature, pressure, lithological feature and water content of the source are main factors influencing the generation of LIPs. The former three factors have been extensively studied by previous researches, but whether or not and how the water in mantle had influenced the generation of LIPs are known little at present. In this paper, we have reviewed previous studies on water content of the LIPs, and introduced a new method for estimating the "primary" water content of the LIPs through the inversion by using the measured H2O content of early-crystallized clinopyroxene phenocryst using FTIR and the partition coefficient of water between the clinopyroxene phenocryst and melt. On the basis of two case studies of the Tarim and Emeishan LIPs, we have comprehensively evaluated the effects of temperature, pressure, lithological feature and water content of the source, and pointed out that the LIPs could be only produced when all these factors are simultaneously presented.
作者
陈欢
顾笑龑
夏群科
CHEN Huan;GU Xiao-yan;XIA Qun-ke(School of Earth Sciences, Zhejiang University, Hangzhou 310027 , China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2019年第2期248-259,共12页
Bulletin of Mineralogy, Petrology and Geochemistry
关键词
水含量
大火成岩省
大陆溢流玄武岩
岩浆作用
单斜辉石斑晶
water content
large igneous province
continental flood basalts
magmatism
clinopyroxene phenocryst
