Trace element partitioning between amphibole and hydrous silicate glasses at 0.6–2.6 GPa
Trace element partitioning between amphibole and hydrous silicate glasses at 0.6–2.6 GPa
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0.6-2.6 GPa 下角闪石和水合硅酸盐玻璃之间的微量元素分配
DOI：
10.1007/s11631-019-00322-4
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Zhou Wenge
中科院分区：
文献类型：
--
作者：
Zhang Bo;Hu Xianxu;Li Peng;Tang Qizhe;Zhou Wenge
实验测定了33种微量元素（Sc、Ti、V、Cr、Co、Rb、Sr、P、Y、Zr、Nb、Cs、Ba、K、La、Ce、Pr、Nd、Sm、Eu、Gd、Tb、Dy、Ho、Er、Tm、Yb、Lu、Hf、Ta、Pb、Th、U）在角闪孔与硅酸盐玻璃间的配分行为。在多砧装置上获得了含水玄武岩熔体在0.6 GPa/860℃~ 2.6 GPa/970℃范围内的结晶产物。采用电子探针和激光烧蚀电感耦合等离子体质谱联用技术测定了角闪孔和玻璃的主微量元素组成。主要矿物相为钙质角闪洞，共生玻璃成分为闪长岩、花岗闪长岩和花岗岩。稀土元素的相容性在915℃时升高，在970℃时降低，但随着压力的增加，大多数稀土元素的相容性呈现持续显著的升高。对于高场强元素、大离子亲石元素，锕系元素的配伍性随着温度或压力的升高而降低，而过渡金属的配伍性在温度-压力条件下持续增加。通过数学和图形拟合，我们确定了理想离子半径（r0, 1.01-1.04 Å）、无应变分配系数（D0, 1.18-1.58）和表观杨氏模量（E, 142-370 GPa）的最佳拟合值。稀土元素在915℃时升高，在0.6 GPa时在970℃下降。然而，在0.6 ~ 2.6 GPa和970℃时，这些值与角闪石-玻璃对中稀土元素的压力成正比。所得的最佳拟合值基本不变，随温度和压力的升高有增大的趋势。对于不同的熔体成分，分配系数有明显的差异。当淬火玻璃为花岗闪长岩或花岗岩时，稀土元素在角闪孔中的富集程度高于调性玻璃。
Partitioning behavior between amphibole and silicate glass of thirty-three minor and trace elements (Sc, Ti, V, Cr, Co, Rb, Sr, P, Y, Zr, Nb, Cs, Ba, K, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf, Ta, Pb, Th, and U) have been determined experimentally. Products of crystallization of hydrous basalt melts from 0.6 GPa/860 °C up to 2.6 GPa/970 °C were obtained in a multi-anvil apparatus. Major and trace element compositions of amphibole and glass were determined with a combination of electron microprobe and laser ablation inductively coupled plasma mass spectrometry. The main mineral phase is calcic amphibole, and the coexisting glass compositions are tonalite, granodiorite, and granite. The compatibility of rare earth elements increase at 915 °C and then decrease at 970 °C, but the compatibility of most of these elements shows a continued, significant increase with increasing pressure. For high-field strength elements, large ion lithophile elements, actinide compatibility decrease with increasing temperature or pressure, but transition metals show a continued increase in compatibility within the temperature–pressure conditions. From mathematical and graphical fitting, we determined best-fit values for the ideal ionic radius (r0, 1.01–1.04 Å), the strain-free partition coefficient (D0, 1.18–1.58), and apparent Young’s modulus (E, 142–370 GPa) for the M4 site in amphibole according to the lattice strain model. Thefor rare earth elements rises at 915 °C and then drops at 970 °C at 0.6 GPa. However, thevalues are positively proportional to the pressure for rare earth elements in the amphibole-glass pairs at 0.6–2.6 GPa and 970 °C. Furthermore, the derived best-fit values forandare almost constant and trend to increase with rising temperature and pressure, respectively. The partition coefficient is distinctly different for different melt compositions. The rare earth elements become more enriched in amphibole if the quenched glass is granodiorite or granite compared to the tonalitic glasses.