PARTITION-COEFFICIENTS FOR OLIVINE-MELT AND ORTHO-PYROXENE-MELT SYSTEMS
PARTITION-COEFFICIENTS FOR OLIVINE-MELT AND ORTHO-PYROXENE-MELT SYSTEMS
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DOI：
10.1007/bf00306480
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发表时间：
1991-01-01
影响因子：
3.5
通讯作者：
RUSSELL, D
中科院分区：
文献类型：
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作者：
BEATTIE, P;FORD, C;RUSSELL, D
热力学分析表明，橄榄石熔体和斜方辉石熔体分配系数的许多元素应近似线性函数D（Mg）。 这些简单的关系可以与矿物化学计量的约束相结合，以允许直接计算这些元素的分配系数，如果熔融相的主要元素化学是已知的。 一个大的数据集的已发表和未发表的实验矿物熔体对组合物的范围内科马提岩安山岩，允许确定的经验常数，这种计算所需的。 这些参数化的精度证明通过比较计算值与那些观察到的。 从实验矿物熔体对测得的phenococcus矩阵分配系数的比较表明，实验确定的分配系数是相当于那些在岩浆过程中。 因此，没有显着的动力学因素排除岩浆分区被复制的实验时间尺度。 该模型提供了一套简单的测试平衡，并使岩浆分馏橄榄石或斜方辉石的化学演化建模。 本文还提出了一个经验公式，可用于实验室化学分析中斜方辉石与其它低钙辉石的鉴别。
Thermodynamic analysis shows that olivine-melt and orthopyroxene-melt partition coefficients for many elements should be approximately linear functions of D(Mg). These simple relationships can be combined with the constraint of mineral stoichiometry to allow the direct calculation of partition coefficients for these elements if the major element chemistry of the melt phase is known. A large dataset of published and unpublished experimental mineral-melt pairs for compositions in the range komatiite to andesite has allowed the determination of the empirical constants required for this calculation. The precision of these parameterisations is demonstrated by comparing the values calculated with those observed. Comparison of phenocryst-matrix partition coefficients with those measured from experimental mineral-melt pairs demonstrates that experimentally determined partition coefficients are equivalent to those in magmatic processes. There are therefore no significant kinetic factors precluding magmatic partitioning being reproduced on an experimental timescale. The model provides a set of simple tests for equilibrium and enables the chemical evolution of a magma fractionating olivine or orthopyroxene to be modelled. An empirical equation for distinguishing orthopyroxene from other low-Ca pyroxenes in chemical analyses of experimental runs is also presented.