Clinopyroxene is a key fractionating phase in alkaline magmatic systems, but its impact on metal enrichment processes, and the formation of REE + HFSE mineralisation in particular, is not well understood. To constrain the control of clinopyroxene on REE + HFSE behaviour in sodic (per)alkaline magmas, a series of internally heated pressure vessel experiments was performed to determine clinopyroxene–melt element partitioning systematics. Synthetic tephriphonolite to phonolite compositions were run H₂O-saturated at 200 MPa, 650–825°C with oxygen fugacity buffered to log f O₂ ≈ ΔFMQ + 1 or log f O₂ ≈ ΔFMQ +5. Clinopyroxene–glass pairs from basanitic to phonolitic fall deposits from Tenerife, Canary Islands, were also measured to complement our experimentally-derived data set. The REE partition coefficients are 0·3–53, typically 2–6, with minima for high-aegirine clinopyroxene. Diopside-rich clinopyroxene (Aeg_5–25) prefer the MREE and have high REE partition coefficients (D_Eu up to 53, D_Sm up to 47). As clinopyroxene becomes more Na- and less Ca-rich (Aeg_25–50), REE incorporation becomes less favourable, and both the ^VIM1 and ^VIIIM2 sites expand (to 0·79 Å and 1·12 Å), increasing D_LREE/D_MREE. Above Aeg₅₀ both M sites shrink slightly and HREE (^VIr_i ≤ 0·9 Å ≈ Y) partition strongly onto the ^VIM1 site, consistent with a reduced charge penalty for REE³⁺ ↔ Fe³⁺ substitution. Our data, complemented with an extensive literature database, constrain an empirical model that predicts trace element partition coefficients between clinopyroxene and silicate melt using only mineral major element compositions, temperature and pressure as input. The model is calibrated for use over a wide compositional range and can be used to interrogate clinopyroxene from a variety of natural systems to determine the trace element concentrations in their source melts, or to forward model the trace element evolution of tholeiitic mafic to evolved peralkaline magmatic systems.

中文翻译：

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苏打碱性岩浆中的次氯环戊烯/熔体痕量元素分配

Clinopyroxene是碱性岩浆系统中的关键分馏阶段，但对金属富集过程的影响，尤其是REE + HFSE矿化的形成，尚未得到很好的理解。为了限制对苏铁碱（碱性）岩浆中金盏花对REE + HFSE行为的控制，进行了一系列内部加热的压力容器实验，以确定金盏花－熔融元素分配系统。合成tephriphonolite到响组合物运行和配置H ₂在200兆帕，650-825 O型饱和℃下用氧逸度缓冲的登录˚F Ò ₂ ≈ΔFMQ+ 1或log ˚F Ò ₂≈ΔFMQ+5。还测量了来自加那利群岛特内里费岛的从玄武岩到音石质秋季沉积物的斜辉石-玻璃对，以补充我们的实验数据集。REE分配系数为0·3-53，通常为2-6，对于高烟碱的斜py石具有最小值。富含透辉石的clinopyroxene（Aeg _5–25）首选MREE，并且具有高REE分配系数（D _Eu最高为53，D _Sm最高为47）。随着斜茂铁的Na含量增加而Ca含量降低（Aeg _25–50），REE掺入变得越来越不利，^VI M1和^VIII M2的位点都扩大（分别达到0·79Å和1·12Å），从而增加了D _LREE / D _MREE。上述AEG ₅₀两者M个地点略微收缩和重稀土（^VI ř_我≤0·9 A≈Y）分区强烈到^VI M1站点，具有减少的电荷罚REE一致³⁺ ↔的Fe ³⁺替代。我们的数据与大量文献数据库相辅相成，限制了一个经验模型，该模型仅使用矿物主要元素组成，温度和压力作为输入，即可预测斜比重金属和硅酸盐熔体之间的痕量元素分配系数。该模型经过校准，可在很宽的成分范围内使用，可用于查询各种天然系统中的次氯环戊烯，以确定其源熔体中的痕量元素浓度，或正向建模托菲基铁镁质的痕量元素演变为演化的碱性碱性岩浆。系统。