摘要
厘定各种元素在磷灰石和熔体间的分配行为及其控制因素对于磷灰石在地质研究中的应用具有重要意义。本文基于相平衡实验数据对一些关键元素在磷灰石中的分配行为及控制因素进行了总结。挥发分F、Cl、OH在磷灰石中的分配不符合能斯特定律,交换系数可以更好地描述它们的分配行为;S的分配受控于熔体的氧逸度和S含量;Mn、Mg、Sr、REE、Th、U的分配不同程度的受熔体成分或聚合度影响。此外,REE的分配还受元素替换机制和富REE矿物(如独居石、褐帘石)结晶作用的影响,独居石结晶的同时还会影响Th的分配。根据不同元素的分配行为,可利用磷灰石的成分限定岩浆的挥发分含量和氧逸度、探讨火山岩与侵入岩的联系、示踪岩浆的演化等,从而拓展磷灰石在地质研究中的应用。
To determine partitioning behaviors of trace elements between apatite and melt and their controlling factors is of important significance for applications of apatite in geological researches.This study has summarized partitioning behaviors of some key elements in apatite and their controlling factors based on data of phase equilibrium experiments.The partitioning behaviors of F,Cl,and OH in apatite do not follow the Nernst Law but can be better described by the exchange coefficient.The partitioning behavior of S in apatite was affected by oxygen fugacity and S content of the melt.Melt composition or polymerization had affected in different extent the partitioning behaviors of Mn,Mg,Sr,REE,Th,and U in apatite.The partitioning behaviors of REE were also affected by their element substitution mechanisms and crystallization behaviors of REE-rich minerals(eg,monazite and allanite).The crystallization behavior of monazite also affects the partitioning behavior of Th in apatite.On the basis of the partitioning behaviors of different elements in apatite,apatite compositions can be used to constrain contents of volatiles and oxygen fugacity of the magma,and then to explore the relationship between volcanic rocks and intrusive rocks,and to decipher the evolution of magma.Thus,the applications of apatite in geological studies can be extended.
作者
詹琼窑
朱弟成
王青
王棋
ZHAN Qiong-yao;ZHU Di-cheng;WANG Qing;WANG Qi(State Key Laboratory of Geological Processes and Mineral Resources,School of Earth Science and Resources,China University of Geosciences(Beijing),Beijing 100083,China)
出处
《矿物岩石地球化学通报》
CAS
CSCD
北大核心
2022年第6期1087-1099,I0002,I0003,共15页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
国家自然科学基金资助项目(42121002,42102045)。
关键词
磷灰石
分配系数
熔体聚合度
磷灰石饱和温度
岩浆挥发分
apatite
partition coefficient
melt polymerization
apatite saturation temperature
magma volatile
