Water in the Mantle; A Scoping Proposal

地球的宜居性从根本上取决于其表面液态水的可持续存在，但水在创造生命平台方面发挥的作用远远大于简单地为地球表面的生命和气候提供媒介。地幔水分的微小变化改变了矿物的性质，特别是它们在地幔中的粘度(Mei和Kohlstedt JGR105,21457-21469,2000年)，对地幔对流的模式和效率产生了根本影响(McGoven和Schubert EPSL 96，27-37,1989)，甚至可能决定不相容元素在地幔中的分布及其对地表系统的可获得性(Bercovici和Karato Natural 4125，39-44,2003年)。对流反过来也是行星冷却的主要机制，控制着洋壳的生产、大陆的解体、板块的运动和山脉的形成，以及水和其他挥发物进出地幔的流量。很明显，地幔对流决定并可能调节我们星球的宜居性，然而我们对地球深处对这一系统的基本控制，特别是水在地质时期的关键作用的基本理解是令人遗憾的。

The habitability of Earth depends fundamentally on the sustainable presence of liquid water at its surface, but water plays a far greater role in creating a platform for life than simply providing the medium for life and climate at the surface. Small variations in the water content of the mantle changes the minerals properties and specifically their viscosity in the mantle (Mei and Kohlstedt JGR 105, 21457-21469, 2000) with fundamental repercussions on the mode and efficiency of mantle convection (McGovern and Schubert EPSL 96, 27-37, 1989) and may even determine the distribution of incompatible elements in the mantle and their availability to surface systems (Bercovici and Karato Nature 4125, 39-44, 2003). Convection in turn, as well as being the principle mechanism for planetary cooling, controls ocean crust production; continental breakup; plate movement and mountain creation; and flux of water and other volatiles into and out of the mantle. It is clear that mantle convection determines and possibly regulates the habitability of our planet, yet our basic understanding of fundamental controls of this system by the deep Earth, and specifically the critical role of wate over geological time, is woeful.