论文标题
Vaporock：蒸发硅酸盐融化的热力学，用于建模火山和岩浆海洋气氛
VapoRock: Thermodynamics of vaporized silicate melts for modeling volcanic outgassing and magma ocean atmospheres
论文作者
论文摘要
硅酸盐蒸气在行星进化中起着关键作用，尤其是在岩石岩浆海洋氛围中占主导地位的岩石行星形成的早期阶段。我们的开源热力学建模软件“ Vaporock”将熔体模型（Ghiorso等，1995）与来自多个热化表的气体特性结合在一起（例如，Chase等，1998）。 Vaporock在所需温度和氧散发器（FO2，或O2的局部压力）下，在系统中使用岩浆液体在SI-MG-FE-FE-FE-AL-CA-NA-K-TI-CR-O中计算出34个气态物种的部分压力。与实验的比较表明，压力和熔融氧化物活性（在许多数量级上有所不同）被复制到〜3以内，与测量不确定性一致。我们还针对多种火成岩组合物进行基准测试，包括散装硅酸盐地球，预测可比较的元素蒸气丰度（Na，ca，＆al）或更现实（K，Si，Si，Mg，Fe，Fe和Ti）比封闭的磁磁岩浆代码（knode-oure-Source Magma Code（keles-oure-Source Magma Code）（由10-300的因素使用10-300）。蒸气丰度严重取决于液体成分的活性。校准了蒸气的熔体模型，并在天然火成岩液体上进行了广泛的测试。相比之下，岩浆的液体模型假定了一组有限的化学简化伪物种的理想混合物，该物种仅近似于典型的多组分天然硅酸盐熔体的非理想组成相互作用。最后，我们探讨了SIO和SIO2的相对丰度如何在devotalized exoplanetary大气中提供具有光谱可测量的氧气散发性的，这可能会限制超过甲层外膜的FO2。
Silicate vapors play a key role in planetary evolution, especially dominating early stages of rocky planet formation through outgassed magma ocean atmospheres. Our open-source thermodynamic modeling software "VapoRock" combines the MELTS liquid model (Ghiorso et al., 1995) with gas-species properties from multiple thermochemistry tables (e.g., Chase et al., 1998). VapoRock calculates the partial pressures of 34 gaseous species in equilibrium with magmatic liquid in the system Si-Mg-Fe-Al-Ca-Na-K-Ti-Cr-O at desired temperatures and oxygen fugacities (fO2, or partial pressure of O2). Comparison with experiments shows that pressures and melt-oxide activities (which vary over many orders of magnitude) are reproduced to within a factor of ~3, consistent with measurement uncertainties. We also benchmark the model against a wide selection of igneous rock compositions including bulk silicate Earth, predicting elemental vapor abundances that are comparable (Na, Ca, & Al) or more realistic (K, Si, Mg, Fe, & Ti) than those of the closed-source MAGMA code (with maximum deviations by factors of 10-300 for K & Si). Vapor abundances depend critically on the activities of liquid components. The MELTS model underpinning VapoRock was calibrated and extensively tested on natural igneous liquids. In contrast, MAGMA's liquid model assumes ideal mixtures of a limited set of chemically simplified pseudo-species, which only roughly approximates the non-ideal compositional interactions typical of many-component natural silicate melts. Finally, we explore how relative abundances of SiO and SiO2 provide a spectroscopically measurable proxy for oxygen fugacity in devolatilized exoplanetary atmospheres, potentially constraining fO2 in outgassed exoplanetary mantles.
