Trace element partitioning between pyrochlore, microlite, fersmite and silicate melts
Trace element partitioning between pyrochlore, microlite, fersmite and silicate melts
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烧绿石、微晶石、钙铁矿和硅酸盐熔体之间的微量元素分配
DOI：
10.1186/s12932-020-00072-w
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发表时间：
2020
影响因子：
2.3
通讯作者：
J. Berndt
中科院分区：
文献类型：
--
作者：
S. Klemme;J. Berndt
实验测定了微量元素在辉石族矿物（Ca 2（Nb，Ta）2 O 6（O，F））、钙铁闪石（CaNb 2 O 6）和硅酸盐熔体之间的分配系数（D）。结果表明，在SiO2不饱和岩浆演化过程中，辉石岩和费斯芒岩对微量元素具有强烈的分异作用。烧绿石有效地从Nb和Ta中分离Zr和Hf，D Zr和D Hf低于或等于1，D Nb和D Ta显著高于1。我们发现，D钽辉石族矿物/硅酸盐熔体总是高于D铌，这与所有其他富钛矿物，如钙钛矿，金红石，钛铁矿或Fe-Ti尖晶石的HFSE分配。我们的实验分配系数还表明，在氧化条件下，D Th高于相应的D U，这意味着辉石族矿物可能压裂硅酸盐岩浆中的U和Th。稀土元素的分配系数接近1，只有轻稀土元素与辉石岩族矿物相容，这解释了岩浆辉石岩中稀土元素含量较高的原因。
We present experimentally determined trace element partition coefficients (D) between pyrochlore-group minerals (Ca 2 (Nb,Ta) 2 O 6 (O,F)), Ca fersmite (CaNb 2 O 6 ), and silicate melts. Our data indicate that pyrochlores and fersmite are able to strongly fractionate trace elements during the evolution of SiO 2 -undersaturated magmas. Pyrochlore efficiently fractionates Zr and Hf from Nb and Ta, with D Zr and D Hf below or equal to unity, and D Nb and D Ta significantly above unity. We find that D Ta pyrochlore-group mineral/silicate melt is always higher than D Nb , which agrees with the HFSE partitioning of all other Ti–rich minerals such as perovskite, rutile, ilmenite or Fe-Ti spinel. Our experimental partition coefficients also show that, under oxidizing conditions, D Th is higher than corresponding D U and this implies that pyrochlore-group minerals may fractionate U and Th in silicate magmas. The rare earth element (REE) partition coefficients are around unity, only the light REE are compatible in pyrochlore-group minerals, which explains the high rare earth element concentrations in naturally occurring magmatic pyrochlores.
影响因子：
3.5
作者：
C. H. Wijbrans;S. Klemme;J. Berndt;C. Vollmer
通讯作者：
C. H. Wijbrans;S. Klemme;J. Berndt;C. Vollmer