摘要
在硅酸盐液相不混溶过程中,高电荷密度(HCD)阳离子优先进入较基性的不混溶熔体相中,这与它们在岩浆分离结晶过程中的行为正好相反.根据这个原理,可区分岩石(矿石)是液相不混溶成因还是结晶分异成因.HCD阳离子在两共轭液相中的分配主要由其聚合程度强弱决定.在基性熔体中,非桥氧(NBO)数较多,要求更多的HCD阳离子以求配位.两液相中结晶相的存在会严重影响HCD阳离子的配分性质.
Theoretical analysis and experimental and empirical data indicate that HCD cations will be preferentially partitioned into a basic melt coexisting with an immiscible acidic melt. This preferential partitioning is due to the greater availability of NBO, required to coordinate with the HCD cations in the basic melt. The pattern of enrichment of HCD cations in the basic melt is antithetical to the usual pattern of enrichment of HCD cations in the residual acidic melt produced by fractional crystallization. This contrast in behavior of the HCD cations can be used to distinguish rocks produced by processes of silicate-liquid immiscibility from those produced by fractional crystallization. The presence of solid phase, which is in equilibrium with both immiscible liquids, can seriously distort the partitioning patterns of the HCD elemnts.
出处
《地质科技情报》
CAS
CSCD
北大核心
1990年第3期37-42,共6页
Geological Science and Technology Information
