Unpicking global mantle convection influences from the local: investigating asthenospheric versus lithospheric constraints on the evolution of

阐明全球地幔对流对局部地幔对流的影响：研究软流圈与岩石圈对地幔演化的限制

• 批准号: 2609877
• 金额: --
• 依托单位: University of Leicester
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2609877
• 关键词: Unpicking; global; mantle; convection; influences

Unpicking global mantle convection influences from the local: investigating asthenospheric versus lithospheric constraints on the evolution of landscapesThis study will examine the role large-scale, global, mantle convection patterns might play on the long-term development of the Earth's landscape, versus higher-resolution, localised studies that focus on features of basal architecture of the lithosphere, or presence of subducted slabs (e.g. Kaislaniemi & van Hunen 2014). Much of the debate around long-term landscape evolution, centres around lithospheric response to dynamics of the mantle beneath, versus the architecture of the lithosphere itself, or its history of loading or heating (e.g. Wheeler & White, 2002). Both geophysical and numerical studies on global mantle structure reveal broad-scale convection patterns that show the flow of mantle beneath plates (e.g. Barry et al., 2017), but such studies do not include higher resolution details, such as asthenospheric interactions with the irregular base of the lithosphere, or localised disrupted flow patterns around downwelling slabs (e.g. Xu & Zhao, 2009; Zahirovic et al., 2016). Nor do they take account of dynamics within the lithosphere, such as basin development or regions of uplift. This project will look at three contrasting regions, which characterise different complexities of flow regimes within the shallow mantle: east Africa - an intraplate setting dominated by a large-scale mantle upwelling and lacking subducted slabs within the shallow mantle; south-east Asia - an area dominated by the complex interaction of downgoing slabs and ongoing subduction; and central Asia - an intraplate area with no obvious large-scale plume or active subduction but has slabs deep within the upper mantle from former subduction events (Figure 1).All these areas have a wealth of information about the nature of the landscape development, with information about the timing and extent of basin development, regions of uplift, details of distribution of magmatism deriving from the mantle, and detailed geophysical constraints on the architecture of the lithosphere. This project will examine how much the presence of slabs influences local mantle convection patterns over global patterns. How much does a mantle plume upwelling influence localised flow at the base of the lithospheric mantle? And how much does the resultant mantle flow influence the evolving landscape above it, with development of basins or upland areas?

从局部的地幔对流中分离出全球地幔对流的影响：研究软流圈与岩石圈对地幔演化的制约这项研究将研究大规模的全球地幔对流模式可能对地球景观的长期发展所起的作用，而高分辨率的局部研究则侧重于岩石圈基底结构的特征，或俯冲板片的存在（例如Kaislaniemi &货车Hunen 2014）。围绕长期景观演化的大部分争论都围绕着岩石圈对地幔动力学的响应，而不是岩石圈本身的结构，或其加载或加热的历史（例如，惠勒和白色，2002）。对全球地幔结构的地球物理和数值研究都揭示了大规模的对流模式，显示了板块下方的地幔流动（例如，巴里等人，2017年），但这些研究不包括更高分辨率的细节，如软流圈与岩石圈不规则基底的相互作用，或下涌板块周围的局部中断流动模式（例如，Xu & Zhao，2009年; Zahirovic等人，2016年）。它们也没有考虑到岩石圈内的动力学，如盆地发展或隆起地区。该项目将研究三个对比鲜明的区域，它们反映了浅地幔内流动状况的不同复杂性：东非-一个以大规模地幔上涌为主的板内环境，浅地幔内缺乏俯冲板片;东南亚-一个以下行板片和持续俯冲的复杂相互作用为主的地区;中亚--板内地区没有明显的大规模地幔柱或活跃的俯冲作用，但在上地幔深处有来自前俯冲事件的板片（图1）。所有这些地区都有大量关于景观开发性质的信息，以及关于流域开发的时间和范围的信息，隆起的区域，来自地幔的岩浆活动的分布细节，以及岩石圈结构的详细地球物理约束。这个项目将研究板块的存在对局部地幔对流模式的影响程度。地幔柱上涌对岩石圈地幔底部局部流动的影响有多大？随着盆地或高地地区的发展，由此产生的地幔流对上面不断演变的景观有多大影响？