Global plate tectonics and mantle convection with damage memory

全球板块构造和具有损伤记忆的地幔对流

• 批准号: 1853856
• 负责人: Thorsten Becker
• 金额: $ 37.5万
• 依托单位: University of Texas at Austin
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-15 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1853856&HistoricalAwards=false
• 关键词: Global; plate; tectonics; mantle; convection

Plate tectonics is fundamental for Earth's evolution and the surface expression of mantle convection. However, it is unclear how the narrow and strongly deforming boundaries between the more rigid plates form. The reactivation of plate boundaries, in particular, gives the continental plates a long-term hysteresis with profound implications for tectonics. This project seeks to better understand the causes and consequences of damage memory in convection. Funding will support a female graduate student and speak to issues outside geodynamics including the quest for a general law describing fault behavior from the seismic cycle to long-term Earth evolution. The project will also support new international collaborations, and research outcomes will be disseminated widely, including for UT Austin's GeoFORCE K-12 outreach program.This project will implement strain-dependent weakening into global, numerical convection models in order to explore the style of "plate tectonics" that is generated by visco-plastic mantle flow. Incorporating such rheological memory will allow study of the full range of tectonic behavior, including how plate boundary evolution and plate motions are linked with the deep mantle. A range of viscous damage formulations will be explored and benchmarked against grain-size evolution theories and other suggested mechanisms for strain-localization, such as formation of shear bands and mechanical anisotropy due to lattice preferred orientation of olivine. Model results will be compared with geological constraints including plate kinematics, with particular focus on the time-dependence of plate boundary geometry, plate speeds and sizes, and seafloor age distributions. The overall goal is to develop a theoretical understanding of the role of tectonic inheritance in terrestrial planet evolution and heat transport.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

板块构造是地球演化和地幔对流地表表现的基础。然而，目前还不清楚更刚性的板块之间狭窄和强烈变形的边界是如何形成的。特别是板块边界的重新活动，使大陆板块具有长期滞后性，对构造有着深远的影响。该项目旨在更好地了解对流中损伤记忆的原因和后果。资金将支持一名女研究生，并就地球动力学以外的问题发表演讲，包括寻求一个描述从地震周期到长期地球演化的断层行为的一般规律。该项目还将支持新的国际合作，研究成果将广泛传播，包括UT Austin的GeoFORCE K-12推广计划。该项目将在全球数值对流模型中实施应变相关弱化，以探索粘塑性地幔流产生的“板块构造”风格。阐明这种流变记忆将允许研究构造行为的全部范围，包括板块边界演化和板块运动如何与深部地幔联系。一系列的粘性损伤配方将探讨和基准对粒度演化理论和其他建议的应变局部化机制，如形成剪切带和机械各向异性由于晶格择优取向的橄榄石。将把模型结果与包括板块运动学在内的地质制约因素进行比较，特别侧重于板块边界几何形状的时间依赖性、板块速度和大小以及海底年龄分布。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Role of strain-dependent weakening memory on the style of mantle convection and plate boundary stability

应变相关的弱化记忆对地幔对流类型和板块边界稳定性的作用

• DOI: 10.1093/gji/ggz167
• 发表时间: 2019
• 期刊: Geophysical Journal International
• 影响因子: 2.8
• 作者: Fuchs, Lukas;Becker, Thorsten W
• 通讯作者: Becker, Thorsten W

Plume‐Slab Interactions Can Shut Off Subduction

地幔柱与板片的相互作用可以阻止俯冲作用

• DOI: 10.1029/2022gl099286
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Heilman, Erin;Becker, Thorsten W.
• 通讯作者: Becker, Thorsten W.

Deformation Memory in the Lithosphere: A Comparison of Damage‐dependent Weakening and Grain‐Size Sensitive Rheologies

岩石圈中的变形记忆：损伤依赖性弱化和颗粒尺寸敏感流变学的比较

• DOI: 10.1029/2020jb020335
• 发表时间: 2021
• 期刊: Journal of Geophysical Research: Solid Earth
• 作者: Fuchs, Lukas;Becker, Thorsten W.
• 通讯作者: Becker, Thorsten W.

Convection in Thin Shells of Icy Satellites: Effects of Latitudinal Surface Temperature Variations

• DOI: 10.1029/2018je005799
• 发表时间: 2019-08
• 期刊: Journal of Geophysical Research: Planets
• 作者: M. Weller;L. Fuchs;T. Becker;K. Soderlund

On the Role of Rheological Memory for Convection‐Driven Plate Reorganizations

流变记忆对对流驱动板重组的作用

• DOI: 10.1029/2022gl099574
• 发表时间: 2022
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Fuchs, L.;Becker, T. W.
• 通讯作者: Becker, T. W.