Modelling the reservoirs and fluxes of Zn in Earth's crust and mantle requires data on the solubility of its mineral hosts and ores in coexisting fluids, as well as on the complexation of Zn in these fluids as a function of fluid composition, pressure, and temperature. However, due to experimental challenges, the availability of such data is limited to pressures below 1 GPa, which are only representative of upper crust conditions.

Here, we report the effects of salinity (0–4.5 m total Cl), pressure (0.5–6 GPa) and temperature (25–400 °C) on the solubility of smithsonite (ZnCO₃) and speciation of Zn in aqueous fluids. Solubilities at mineral-fluid equilibria and Zn speciation in the coexisting aqueous fluids were determined in situ at high pressure-temperature (P-T) conditions by synchrotron X-ray fluorescence (XRF) and X-ray absorption spectroscopy (XAS) using resistively heated diamond anvil cells (RH-DAC). The solubility of smithsonite increases with salinity, pressure, and temperature. In agreement with previous studies, conducted at lower pressures (below 1 GPa), we observed a gradual transition from octahedral hydrated [Zn(H₂O)₆]²⁺ to tetrahedral hydrated and chlorinated [Zn(H₂O)_4-nCl_n]^2-n (n = 1–4) complexes with increasing salinity and temperature. Our results suggest that these tetrahedral complexes remain stable under the conditions relevant to cold slab dehydration. This change of coordination further enhances the solubility of smithsonite in Cl-rich fluids and provides a likely mechanism for the efficient uptake of Zn by slab-derived fluids.

要模拟地壳和地幔中Zn的储层和通量，需要有关其矿物主体和矿石在共存流体中的溶解度以及这些流体中Zn的络合物随流体组成，压力和温度变化的数据。但是，由于实验上的挑战，此类数据的可用性仅限于低于1 GPa的压力，该压力仅代表上地壳条件。

在这里，我们报告了盐度（总Cl含量为0-4.5 m），压力（0.5-6 GPa）和温度（25-400°C）对铁锌矿（ZnCO ₃）的溶解度和锌在水流体中的形态的影响。通过使用电阻加热金刚石砧座的同步辐射X射线荧光（XRF）和X射线吸收光谱（XAS）在高压-高温（PT）条件下原位测定共存水流体中矿物流体平衡时的溶解度和Zn形态电池（RH-DAC）。铁矿的溶解度随盐度，压力和温度的升高而增加。与之前在较低压力（低于1 GPa）下进行的研究一致，我们观察到了八面体水合[Zn（H ₂ O）₆ ]的逐渐转变。 随着盐度和温度的升高，₂ ⁺至四面体水合氯化[Zn（H ₂ O）_4-n Cl _n ] ^2-n（n = 1-4）络合物。我们的结果表明，这些四面体配合物在与冷平板脱水有关的条件下保持稳定。这种配位变化进一步增强了铁锌矿在富Cl流体中的溶解度，并为板坯衍生流体有效吸收Zn提供了一种可能的机制。