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Rheological controls on slab delamination

板分层的流变控制

基本信息

批准号：
NE/T006617/1
负责人：
David Dobson
金额：
$ 68.16万
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：
2020
资助国家：
英国
起止时间：
2020 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FT006617%2F1
关键词：
Rheological controls slab delamination

项目摘要

Subducted oceanic lithosphere displays a range of complex behaviours including penetration into the lower mantle, stagnation in the transition zone and ponding at, or just below, the 660 km seismic discontinuity, and intermediate behaviour between these end-members. At a finer scale, the MORB component is thought to mechanically decouple from the slab core to produce seismic scatterers in the lower mantle and potential reservoirs for enriched OIB material at the core-mantle boundary and the base of the transition zone. The exact behaviour of the slab and its different components will depend on their densities and strengths relative to each other and the surrounding mantle. While the densities of the various rocks and minerals in the mantle are well known our knowledge of their strengths is very poor; geodynamical simulations show a range of slab behaviours dependent on these properties. We will measure the relative strength of the main rocks which comprise the slab (mid-ocean-ridge basalt and depleted peridotite) under the range of pressure and temperature conditions of the subducting slab to ~1000 km depth. This will allow us to assess which phase assemblages of the two compositions along the slab geotherm show the main rheological contrasts and hence better understand the processes of slab deformation and delamination.

俯冲大洋岩石圈表现出一系列复杂的行为，包括渗透到下地幔，停滞在过渡带和积水，或略低于660公里的地震不连续，和这些端元之间的中间行为。在一个更精细的尺度上，MORB组件被认为是机械解耦的板状核心，以产生地震散射体在下地幔和潜在的水库富集OIB材料在核幔边界和基地的过渡带。板块及其不同组成部分的确切行为将取决于它们相对于彼此和周围地幔的密度和强度。虽然地幔中各种岩石和矿物的密度是众所周知的，但我们对其强度的了解非常少;地球动力学模拟显示了一系列取决于这些特性的板块行为。我们将测量在俯冲板片至~1000公里深度的压力和温度条件下，构成板片的主要岩石（洋中脊玄武岩和亏损橄榄岩）的相对强度。这将使我们能够评估这两种组合物的相组合沿着板地热显示主要的流变对比，从而更好地理解板变形和分层的过程。

项目成果

期刊论文数量（6）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Structure and thermal expansion of end-member olivines I: Crystal and magnetic structure, thermal expansion, and spontaneous magnetostriction of synthetic fayalite, Fe 2 SiO 4 , determined by high-resolution neutron powder diffraction

端元橄榄石的结构和热膨胀 I：合成铁橄榄石 Fe 2 SiO 4 的晶体和磁性结构、热膨胀和自发磁致伸缩，通过高分辨率中子粉末衍射测定

DOI：
10.1180/mgm.2023.66
发表时间：
2023
期刊：
Mineralogical Magazine
影响因子：
2.7
作者：
Tripoliti E
通讯作者：
Tripoliti E

Magma mixing between rhyolite and pseudotachylite as the origin for the Glencoe 'Flinty Crush Rock'

流纹岩和假速岩之间的岩浆混合是格伦科“燧石碎岩”的起源

DOI：
10.1144/sjg2023-016
发表时间：
2024
期刊：
Scottish Journal of Geology
影响因子：
0.7
作者：
Dobson D
通讯作者：
Dobson D

Preliminary results from the New Deformation multi-anvil press at the Photon Factory: insight into the creep strength of calcium silicate perovskite

光子工厂新型变形多砧压机的初步结果：深入了解硅酸钙钛矿的蠕变强度

DOI：
发表时间：
2022
期刊：
AGU, Core-Mantle Coevolution: A Multidisciplinary approach
影响因子：
0
作者：
Andrew R Thomson;Y. Nishihara;D. Yamazaki;N. Tsujino;Simon A Hunt;Y. Tsubokawa;K.N. Matsukage;T. Yoshino;T. Kubo;David P Dobson
通讯作者：
David P Dobson

Deformation of Post-Spinel Under the Lower Mantle Conditions

下地幔条件下后尖晶石的变形