Experimental Study of Water at Deep Mantle Conditions

Jeanloz 0001087了解地球深处H2O的性质对于破译水的地球化学循环、可能在地球内部融化的原因以及从地球物理上观察到的地幔性质具有重大意义。热力学分析甚至表明，冰可能存在于深处，俯冲在冰冷的快速下沉的冰块中。该提案要求支持一项为期两年的实验工作，目的是记录1)晶体-结构一致性，2)热状态方程和3)结晶水(Ice VII，以及可能的其他晶型)在高压和温度下的熔化温度，为水相在较低地幔压力下的稳定性和地球物理相关性质(弹性、密度)提供基本限制。

Jeanloz 0001087 Understanding the properties of H2O deep inside the Earth has major implications for deciphering the geochemical cycling of water and the possible initiation of melting inside the planet, as well as the geophysically observed properties of the mantle. Thermodynamic analysis even suggests that ice may be present at depth, subducted within cold rapidly-sinking slabs. The proposal requests support for a 2-year experimental effort intended to document 1) the crystal-structural identity, 2) thermal equation of state and 3) melting temperature of crystalline H2O (Ice VII, and potentially other polymorphs) at high pressures and temperatures, providing fundamental constraints on the stability and the geophysically relevant properties (elasticity, density) of H2O phases at lower-mantle pressures, ~20-80 GPa.