权益分类	功能权益	普通用户	{{item.name}}会员
{{category.name}}	{{benefitItem.name}}

New laboratory constraints on the water content of the mantle

实验室对地幔含水量的新限制

基本信息

批准号：
NE/K002902/1
负责人：
David Dobson
金额：
$ 61.66万
依托单位：
University College London
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2013
资助国家：
英国
起止时间：
2013 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK002902%2F1
关键词：
New laboratory constraints water content

项目摘要

We have long known that the nominally anhydrous mantle minerals, such as can take substantial amounts of water into them (eg 3% for wadsleyite and ringwoodite). We also know that water has a drastic effect on the physical and chemical properties of these minerals, changing phase relations by hundreds of Kelvin and causing order-of-magnitude variations in viscosity, electrical conductivity and vacancy populations. This has created a whole genre of speculation about the water content in the mantle and its effects on mantle dynamics (eg; 'The mid-mantle water filter'; Bercovici and Karato 2003: 'Nine oceans of water in the transition zone'; Smyth et al 1994: 'No water in the transition zone'; Green at al 2010). We have, however, no firm understanding of the water content of the mantle deeper than about 100 km and these papers will remain speculative until we place firm constraints on the water content of the deep mantle. We can do this by combining geophysical inversions for electrical conductivity of the geomagnetic response function with laboratory measurements of the effect of water content on electrical conductivity. This is what the current project will do using cutting-edge designer-diamond anvil cell conductivity measurements with simultaneous infra-red measurements of water content. These new data will be used in Monte Carlo simulations of the geomagnetic response function which invert directly for water content.

我们很早就知道，名义上无水的地幔矿物，例如可以吸收大量的水（例如，瓦兹利石和尖伍德石为 3%）。我们还知道，水对这些矿物质的物理和化学性质有巨大影响，使相关系改变数百开尔文，并导致粘度、电导率和空位数量发生数量级的变化。这创造了关于地幔中的水含量及其对地幔动力学影响的一整套推测（例如，“中地幔水过滤器”；Bercovici 和 Karato 2003：“过渡带中的九大洋水”；Smyth 等人 1994：“过渡带中没有水”；Green 等人 2010）。然而，我们对 100 公里以上的地幔含水量还没有确切的了解，在我们对深部地幔的含水量施加严格限制之前，这些论文仍将是推测性的。我们可以通过将地磁响应函数电导率的地球物理反演与含水量对电导率影响的实验室测量相结合来做到这一点。这就是当前项目将使用尖端设计的金刚石砧池电导率测量和同步红外测量水含量来实现的。这些新数据将用于地磁响应函数的蒙特卡罗模拟，直接反演含水量。