Rare earth element partitioning between titanite and silicate melts: Henry's law revisited
Rare earth element partitioning between titanite and silicate melts: Henry's law revisited
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DOI：
10.1016/j.gca.2006.07.016
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发表时间：
2006-10
影响因子：
5
通讯作者：
Stefan Prowatke;S. Klemme
中科院分区：
文献类型：
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作者：
Stefan Prowatke;S. Klemme
给出了稀土元素(REE)在钛铁矿和一系列不同硅酸盐熔体之间分配的详细实验结果。我们的结果表明，微量元素的亨利分配定律依赖于主体组成、有效的异价取代配对、晶体组成和熔体组成。我们证明了Sm的分配系数强烈依赖于Sm在体系中的体相浓度。稀土元素进入晶体结构的替代机制对微量元素的分配和亨利定律的成立起着重要的作用。我们的数据表明，与仅以痕量形式存在的元素相比，主要元素的替代机制存在明显的差异。我们的实验还清楚地表明，亨利定律的开始取决于所有微量元素的浓度之和，这些元素通过相同的取代机制被结合到晶体中。对于涉及钛铁矿和其他副相的岩浆过程的地球化学模拟，首先评估稀土和其他微量元素是作为痕量元素还是作为主要元素存在，然后才可能选择合适的D值。
We present detailed experimental results on the partitioning of rare earth elements (REE) between titanite and a range of different silicate melts. Our results show that Henry’s law of trace element partitioning depends on bulk composition, the available partners for heterovalent substitution, crystal composition, and melt composition. We illustrate that the partition coefficients for Sm depend very strongly on the bulk concentration of Sm in the system. The substitution mechanism, by which rare earth elements are incorporated into the crystal structure, plays an important role for trace element partitioning and also for the onset of Henry’s law. Our data show that there are clear differences between substitution mechanisms of major elements compared to elements which are present only as traces. Our experiments also clearly show that the onset of Henry’s law depends on the concentrations of the sum of all trace elements which are incorporated into the crystal by the same substitution mechanism. For geochemical modelling of magmatic processes involving titanite, and indeed other accessory phases, it is of crucial importance to first evaluate whether the REE, and other trace elements, are present as traces or as major elements, only then appropriate D values may be chosen.