| 不混溶熔体体系的元素分配系数及其影响因素和岩石学、矿床学意义 |
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| 引用本文：干国樑.1993.不混溶熔体体系的元素分配系数及其影响因素和岩石学、矿床学意义[J].地球学报,14(1):115-131. |
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| 中文摘要:不混溶熔体体系的元素分配系数KiM1-M2,揭示了岩浆不混溶作用过程中元素的行为规律。本文给出了涉及到超基性(U)、基性(B)、中性(M)、酸性(A)、碱性(AK)硅酸盐熔体和硫化物(S)、氧化物(O)、碳酸盐(C)熔体的岩浆不混溶体系的元素分配系数,指出:①自M+(包括Al+3、Si+4)→M+2→M+n(n≥3),元素的KiU-B、KiU-M、KiU-A、KiB-MKiB-A、KiM-A均逐渐增大,由<1→≥1→》1;②M+(包括Al+3、Si+4)的KiU-AKiU-M>KiU-B>1,KiB-A>KiB-M>1,KiU-A>KiB-A>KiM-A>1,KiU-M>KiB-M>1。此外,文中讨论了熔体成分(结构)、元素性质、物理化学条件(T、P、fO2)对KiM1-M2的影响,并从热力学角度解释了为什么在熔体中加入高价阳离子、降低温度、升高压力均能加宽熔体的不混溶区,使KiM1-M2>1的元素分配系数增大,使KiM1-M2<1的元素分配系数减小,而加入低价阳离子、升高温度、降低压力则作用相反。最后,分析了KiM1-M2与矿物-熔体和熔体-溶液间元素分配系数的关系以及熔体不混溶作用在内生成矿中的意义。 |
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| ELEMENT PARTITIONING COEFFICIENTS IN IMMISCIBLEMELT SYSTEM INFLUENTIAL FACTORS AND IMPLICATIONS FOR PETROLOGY AND METALLOGENY |
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| Abstract:Element partitioning coefficient in immiscible melt system, which is expressed as KiM1-M2, reveals the behavior regularities of elements in the process of magma immiscibillty. In this paper, element partition coefficients in immiscible melt systems containing ultrabasic(U), basic(B) ,intermediate(M), acid(A), alkaline(AK) silicate melts and sulfide(S), oxide(O), carbonate (O) melts are presented. It is found that: ( 1 )in the order of M+(including Al + 3, Si+4)→M+2→M+n (n≥3), partition coeffieients KiU-B ,KiU-M, KiU-A,KiB-M, KiB-A, KiM-A increase gradually, changing from<1→≥1→》1; ( 2 )as to M+(includingAl+3, Si+4>KiU-AU-M>U-B> KiB-A>B-M> KiU-A>B-A>iM-A>1,KiU-M>KiB-M>1. Moreover, the influences of melt co-mposition and melt structure, element nature, and physico-chemical parameters such as temperature, pressure and oxygen fugacity on KiM1-M2 are discussed, and then the reasons why the addition of high valence cations into melts, the decrease in temperature and the increase in pressure would broaden the immiscibility field of melts and therefore result in the increase in partition coefficients of elements with KiM1-M2>1 and the decrease in partition coefficients of elements with KiM1-M2<1 are thermodynamically studied. Finally, the relationship between KiM1-M2 and mineral-melt, melt-solution element partition coefficients and the role of melt immiscibility in endo-genic mineralization are considered. |
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