The strength of the lower mantle

下地幔的强度

• 批准号: NE/L006898/1
• 负责人: David Dobson
• 金额: $ 47.71万
• 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: 2014
• 资助国家: 英国
• 起止时间: 2014 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FL006898%2F1
• 关键词: strength; lower; mantle

The internal behaviour of the Earth is controlled by convection hence knowledge of mantle viscosity is critical to our understanding. The viscosity of the mantle on large scales has been measured from post-glacial rebound and geoid inversions. These have shown that there is a significant contrast in viscosity between the upper and lower mantles which has been invoked to explain the varied behaviour of subducting slabs at the 660 km discontinuity. The slabs show a range of behaviour from ponding just above the 660 km discontinuity to penetrating the discontinuity and thickening as they enter the lower mantle. It is apparent therefore that the size and impermeability of the 660 km viscosity contrast affects the style of mantle convection and cooling rates but the resolution of the geophysical observations is not sufficient for a complete understanding of the fate of material around the 660 km discontinuity. Here we propose to measure the rheology of the minerals and assemblages present in the transition-zone and lower-mantle and so provide the constraints needed for a fuller understanding of the viscosity contrast between the upper and lower mantles.

地球的内部行为是由对流控制的，因此地幔粘度的知识对我们的理解至关重要。大尺度上地幔的粘度已经从冰后期的回弹和大地水准面反演中测量出来。这些都表明，有一个显着的上地幔和下地幔之间的粘度已被调用来解释在660公里的不连续俯冲板片的不同行为的对比。这些板块表现出一系列的行为，从660公里不连续面上方的积水到穿透不连续面并在进入下地幔时增厚。因此，660 km粘度差的大小和不渗透性显然影响地幔对流和冷却速率的类型，但地球物理观测的分辨率不足以完全了解660 km不连续周围物质的命运。在这里，我们建议测量流变学的矿物和组合存在于过渡带和下地幔，因此提供了更全面的理解上地幔和下地幔之间的粘度对比所需的限制。

项目成果

An Experimental Investigation of the Relative Strength of the Silica Polymorphs Quartz, Coesite, and Stishovite

• DOI: 10.1029/2018gc007842
• 发表时间: 2019-04
• 期刊: Geochemistry
• 影响因子: 3.7
• 作者: S. Hunt;M. Whitaker;E. Bailey;E. Mariani;C. Stan;D. Dobson

Phase diagram and thermal expansion of orthopyroxene-, clinopyroxene-, and ilmenite-structured MgGeO3

斜方辉石、单斜辉石和钛铁矿结构 MgGeO3 的相图和热膨胀

• DOI: 10.2138/am-2021-7685ccby
• 发表时间: 2021
• 期刊: American Mineralogist
• 影响因子: 3.1
• 作者: Hunt S

High-temperature equation of state of vanadium

• DOI: 10.1080/08957959.2015.1123256
• 发表时间: 2016-01
• 期刊: High Pressure Research
• 影响因子: 2
• 作者: W. Crichton;J. Guignard;E. Bailey;D. Dobson;S. Hunt;A. Thomson

Anisotropic diffusion creep in postperovskite provides a new model for deformation at the core-mantle boundary

后钙钛矿中的各向异性扩散蠕变为核幔边界变形提供了新模型

• DOI: 10.1073/pnas.1914826116
• 发表时间: 2019
• 期刊: Proceedings of the National Academy of Sciences
• 作者: Dobson D

The Search for Active Marsquakes Using Subpixel Coregistration and Correlation: Best Practice and First Results

使用子像素配准和相关性搜索活跃火星地震：最佳实践和初步结果

• DOI: 10.1029/2018je005649
• 发表时间: 2018
• 期刊: Planets
• 作者: Grindrod P