Continents in the Mantle Transition Zone? Sediment Recycling and the Geochemical Fertilization of the Deep Mantle

地幔过渡带有哪些大陆？

• 批准号: DP140103841
• 负责人: Dr Robert Rapp
• 金额: $ 11.59万
• 依托单位: The Australian National University
• 依托单位国家: 澳大利亚
• 项目类别: Discovery Projects
• 财政年份: 2014
• 资助国家: 澳大利亚
• 起止时间: 2014-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://dataportal.arc.gov.au/RGS/Web/Grants/DP140103841
• 关键词: Continents; Mantle; Transition; Zone; Sediment

Because of its intrinsic compositional buoyancy, continental crust has traditionally been considered to be unsubductable in the denser underlying mantle. Yet some ocean island basalts carry a geochemical signature of recycled continental material in their plume source in the deep mantle. This project will reconcile this paradox through high-pressure experiments that will simulate subduction of continental sediments into the deep mantle. These experiments will provide the first empirical constraints on the role of sediment-derived fluids in mantle metasomatism and the origin of economically-rich potassic magmas, and the nature of the ultrarefractory continental component that ultimately reaches the plume source for ocean-island basalts.

由于其内在的成分浮力，大陆地壳传统上被认为是不可俯冲的密度更大的下地幔。然而，一些洋岛玄武岩在其地幔深处的地幔柱来源中携带着再循环大陆物质的地球化学特征。该项目将通过高压实验来调和这一矛盾，这些实验将模拟大陆沉积物向地幔深处的俯冲。这些实验将提供第一个经验的限制作用的沉积物衍生流体在地幔交代作用和经济上丰富的钾质岩浆的起源，和性质的超耐火大陆成分，最终达到洋岛玄武岩的羽源。