Theoretical Geochemistry of Planetary Volcanic Gases

越来越多地，对行星的天文观测被用来揭示行星大气层内以及大气层和行星表面之间的活动过程。大气过程的光化学模型的日益复杂，以及大气和表面反应相互作用的计算，将受益于火山气体成分理论模型提供的额外限制。一方面，新的火山气体模型已经成为研究活跃火山的行星体不可或缺的一部分，比如木星卫星Io。另一方面，火山气体组成的理论模型将有助于约束具有火山历史的行星上大气和表面演化的模型。火山气体的丰度和形态反映了火山喷口的压力、温度、氧化状态和母岩浆的成分，所有这些都可以用来探索火山活动的行星体内。米哈伊尔·佐洛托夫博士将领导一个理论地球化学模拟计划，该计划将导致对火山脱气的成分和形态及其对行星体大气和表面的影响的可测试预测。脱气挥发物的大部分成分将包括宇宙化学、陆地火山学和关于挥发物在岩浆中的溶解度的实验数据。这项研究将最大限度地限制岩浆温度、喷口压力和行星内部的氧化状态。这项工作将极大地扩展热力学数据库，以便气-固系统中的化学平衡可以用来模拟火山气体的物种形成，其主体成分、喷口压力、温度和岩浆的氧化状态被确定为可能适合行星体。分析将包括H-C-O-S-Cl-F-N体系中的物种形成。将为火星、金星和水星上的火山脱气开发特定的模型，并进行比较研究。该项目的结果将有助于其他研究人员分析火山脱气对大气和地表化学的影响、火山作用的气候效应、火山喷发的物理以及陆地行星上大气-岩石圈耦合演化。将开发一个用于研究和教育的互动网站，以展示火山脱气对行星上的大气、地球化学、地质和生物过程的重要性。该网站将包括一个代码，以交互模式计算给定温度、压力和体积组成的火山气体的形态。这项研究的一部分将由一名研究生进行，其结果将在全国会议上公布。结果还将被纳入本科生和研究生的地球化学、生物地球化学和宇宙化学课程。将举行一场关于地外火山作用的公开讲座，以及火山在行星、卫星和大型小行星上的脱气作用。***

AST 0507778ZolotovIncreasingly, astronomical observations of planets are being used to reveal the active processes within planetary atmospheres and between atmospheres and planetary surfaces. The growing sophistication of photochemical models for atmospheric processes, and calculations of reactive interaction of atmospheres and surfaces, will benefit from additional constraints provided by theoretical models of volcanic gas compositions. On the one hand, new models for volcanic gases are already integral to studies of planetary bodies with active volcanism such as the Jovian satellite Io. On the other hand, theoretical models of volcanic gas compositions will help constrain models of the evolution of atmospheres and surfaces on planets with volcanic histories. The abundances and speciation of volcanic gases reflect the pressure at volcanic vents, temperatures, oxidation states, and compositions of parental magmas, all of which can be used to explore the interiors of volcanically-active planetary bodies.A program of theoretical geochemical modeling will be led by Dr. Mikhail Zolotov that will lead to testable predictions about the composition and speciation of volcanic degassing and its effect on atmospheres and surfaces of planetary bodies. Bulk compositions of degassed volatiles will be bracketed from cosmochemical, terrestrial volcanological, and experimental data on the solubility of volatiles in magmas. To the greatest extent possible, this study will constrain magma temperature, vent pressures, and the oxidation state of planetary interiors. The work will greatly expand thermodynamic databases so that chemical equilibria in gas-solid systems can be used to model speciation of volcanic gases at the bulk compositions, vent pressures, temperatures and oxidation states of magma determined to be plausible for planetary bodies. The analysis will include speciation in the H-C-O-S-Cl-F-N system. Specific models will be developed for volcanic degassing on Mars, Venus and Mercury, and comparative studies will be performed. Results of this project will assist other researches who analyze the impact of volcanic degassing on atmospheric and surface chemistry, climatic effects of volcanism, and physics of eruptions, as well as coupled atmosphere-lithosphere evolution on terrestrial planets. An interactive website will be developed for research and education to demonstrate the importance of volcanic degassing on atmospheric, geochemical, geological, and biologic processes on planetary bodies. The website will include a code to compute speciation of volcanic gases at given temperature, pressure, and bulk composition in an interactive mode. Portions of the research will be carried out by a graduate student whose results will be presented at national meetings. Results will also be incorporated intogeochemistry, biogeochemistry and cosmochemistry courses for undergraduate and graduatestudents. A public lecture will be given about extraterrestrial volcanism and the role of volcanicdegassing on planets, satellites, and large asteroids. ***