The role of titanite in shaping the geochemistry of amphibolite-derived melts
The role of titanite in shaping the geochemistry of amphibolite-derived melts
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钛矿在塑造角闪岩熔体地球化学方面的作用
DOI：
10.1016/j.lithos.2021.106312
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发表时间：
2021-06
期刊：
影响因子：
3.5
通讯作者：
Kejun Hou
中科院分区：
文献类型：
--
作者：
Lingsen Zeng;Li-E Gao;Linghao Zhao;Kejun Hou
钛铁矿是中下地壳岩石中的主要副相之一，对斜长角闪岩熔体的微量元素和放射性同位素组成具有重要影响。岩相学、锆石U/Pb、全岩元素和同位素辽南混合角闪岩杂岩中一套浅色体的Sr、Nd同位素组成和钛铁矿Nd同位素组成表明：（1）原岩年龄为2450 Ma的角闪岩在160 Ma发生了低度部分熔融，产生了两组浅色体;（2）这些白细胞体保存了大量的Nd同位素不平衡，其来源差异可达10 ~ 100个Nd同位素单位;（3）部分熔融过程中的差异溶解可能导致Nd同位素组成与Ti、V含量呈负相关（代表所呈现的钛铁矿的量）。这些数据表明，在低程度的部分熔融的镁铁质岩石，钛铁矿停留作为残留相，由于无论是不利的纹理或熔融（温度或流体）的条件，并导致亏损的Ti-亲合元素，稀土元素的熔体的发展，和一个大的积极转变Nd同位素组成。类似于其他辅助阶段（例如，锆石，磷灰石，独居石）在变质沉积物来源，这一贡献提出了另一种情况下，可能是常见的高级变质辉石，其中钛铁矿可能是一个关键的阶段，控制关键微量元素（如铌单键Ta，V和稀土元素）的预算和Nd同位素组成的熔体中来自低压熔融的斜长角闪岩或镁铁质岩在各种构造环境。
Titanite, one of the major accessory phases in middle to lower crustal rocks, could play an important role in shaping trace element as well as radiogenic isotope compositions in amphibolite-derived melts. Petrographic, zircon U/Pb, whole-rock element and isotope (Sr and Nd) data on a suite of leucosomes, and titanite Nd isotope compositions from the migmatitic amphibolite complex, southern Liaoning, indicate that (1) the amphibolite with a protolith age of ~2450 Ma underwent low-degree partial melting at ~160 Ma and produced two groups of leucosome; (2) these leucosomes preserved a large magnitude of Nd isotope disequilibrium with up to ~10 epsilon units of difference with respect to their sources; (3) differential dissolution of titanite during partial melting might lead to negative correlations between Nd isotope compositions and respective Ti or V contents (proxy of the amount of titanite presented). These data indicates that during low-degree partial melting of mafic rocks, titanite stays as a residue phase due to either unfavorable texture or melting (temperature or fluid) conditions and leads to the development of melts with depletion in Ti-affinity elements, REE, and a large positive shift in Nd isotope compositions. Similar to other accessory phases (e.g., zircon, apatite, and monazite) in metasedimentary sources, this contribution presents another case that could be common in high-grade metamorphic terranes in which titanite could be a key phase that controls key trace element (e.g. Nbsingle bondTa, V, and REE) budget and Nd isotope compositions in melts derived from low-pressure melting of amphibolite or mafic rocks in various tectonic environments.
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影响因子：
4.9
作者：
W. Fang;Li‐Qun Dai;Yong‐Fei Zheng;Zi‐Fu Zhao;Li-Tao Ma
通讯作者：
W. Fang;Li‐Qun Dai;Yong‐Fei Zheng;Zi‐Fu Zhao;Li-Tao Ma
DOI：
10.18654/1000-0569/2020.09.07
发表时间：
2020
期刊：
岩石学报
影响因子：
--
作者：
赵令浩;曾令森;高利娥;高家昊;王亚飞;张立飞
通讯作者：
张立飞
影响因子：
3.9
作者：
B. Frost;K. Chamberlain;John C. Schumacher
通讯作者：
B. Frost;K. Chamberlain;John C. Schumacher
影响因子：
5.3
作者：
J. Hammerli;A. Kemp;C. Spandler
通讯作者：
J. Hammerli;A. Kemp;C. Spandler
影响因子：
5
作者：
L. Zeng;P. Asimow;J. Saleeby
通讯作者：
L. Zeng;P. Asimow;J. Saleeby