各位老师和同学：
应李元研究员邀请，英国牛津大学田猛博士访问我所，并将于本周四上午做“同位素室学术报告”2018年第26次报告。欢迎大家参加并积极参与讨论！
报告题目：俯冲板片脱挥发分过程的数值模拟（Modelling Devolatilization of Subducting Slabs）
报 告 人：Dr. Meng Tian (University of Oxford, UK)
报告时间：7月26日（周四）上午10:00
报告地点：综合楼701会议室
报告人简介：
田猛博士，2005？2009年于北京大学获得地球化学学士学位，2009？2016于耶鲁大学获得博士学位，2016至今受英国皇家学会牛顿奖学金资助在牛津大学地球科学系做博士后。主要研究兴趣为地球动力学，岩石学中的热力学（相图、扩散）以及相关的科学计算。
Abstract：
Compared with other plate-tectonic boundaries, subduction zones (SZ) host the most drastic mechanical, thermal, and chemical changes. The transport of carbon through this complex environment is crucial to mantle carbon budget but remains the subject of active debate. Synthesis of field studies suggests that carbon subducted with the incoming slab is almost completely returned to the surface environment [Kelemen and Manning, 2015], whereas thermodynamic modelling indicates that a significant portion of carbon is retained in the slab and descends into the deep mantle [Gorman et al., 2006]. To address this controversy and quantify the carbon fluxes within SZs, it is necessary to treat the chemistry of fluid/volatile–rock interaction and the mechanics of porous fluid/volatile migration in a consistent modelling framework. This requirement is met by coupling a thermodynamic parameterization of de/revolatilization with a two-phase flow model of subduction zones.
The two-phase system is assumed to comprise three chemical components: rock containing only nonvolatile oxides, H2O and CO2; the fluid phase includes only the latter two. Perple_X is used to map out the binary subsystems rock+H2O and rock+CO2; the results are parameterised in terms of volatile partition coefficients as a function of pressure and temperature. In synthesising the binary subsystems to describe phase equilibria that incorporate all three components, a Margules coefficient is introduced to account for non-ideal mixing of CO2/H2O in the fluid, such that the partition coefficients depend further on bulk composition. This procedure is applied to representative compositions of sediment, MORB, and gabbro for the slab, and peridotite for the mantle. The derived parameterization of each rock type serves as a lightweight thermodynamic module interfaceable with two-phase flow models of SZs. We demonstrate the application of this thermodynamic module through a simple model of carbon flux with a prescribed flow direction through (and out of) the slab. This model allows us to evaluate the effects of flow path and lithology on carbon storage within the slab.
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