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?

揭开全球地幔对流的局部影响：调查软流圈与岩石圈对地貌演化的制约这项研究将考察大规模、全球、地幔对流模式对地球地貌长期发展的作用，而不是专注于岩石圈基础结构特征或俯冲板块存在的高分辨率本地化研究(例如，Kaislaniemi&van Hunen 2014)。围绕长期地貌演变的大部分争论集中在岩石圈对下面地幔动态的响应，而不是岩石圈本身的结构或其加载或加热的历史(例如Wheeler&White，2002)。对全球地幔结构的地球物理和数值研究都揭示了显示板块下地幔流动的大范围对流模式(例如Barry等人，2017)，但此类研究不包括更高分辨率的细节，例如软流圈与岩石圈不规则底部的相互作用，或下沉板块周围的局部扰动流动模式(例如Xu&赵，2009；Zahirovic等人，2016)。它们也没有考虑岩石圈内的动态，如盆地发展或隆起区。这个项目将着眼于三个不同的区域，它们描述了浅地幔内部流动状况的不同复杂性：东非--以大规模地幔上涌为主导的板内环境，在浅地幔内缺乏俯冲板块；东南亚--一个以下行板块和持续俯冲的复杂相互作用为主的区域；亚洲和中亚--一个板内区，没有明显的大规模羽流或活动俯冲，但在上地幔深处有以前俯冲事件产生的板块(图1)。所有这些地区都有关于景观发展性质的丰富信息，包括关于盆地发展的时间和程度、隆起区、来自地幔的岩浆活动分布细节以及对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全球模式中的地幔对流模式有多大的影响。地幔上涌对岩石圈地幔底部的局部流动有多大影响？随着盆地或高地地区的发展，由此产生的地幔流动对其上方不断演变的地貌有多大影响？