CSEDI Collaborative Research: Deep Mantle Cycling of Oceanic Crust

CSEDI合作研究：洋壳深部地幔循环

• 批准号: 1401270
• 负责人: Edward Garnero
• 金额: $ 55.01万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-08-15 至 2017-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1401270&HistoricalAwards=false
• 关键词: CSEDI; Collaborative; Research; Deep; Mantle

This 2-year research project focuses on investigating the fate of oceanic crust and tectonic plates that dive into Earth's interior at subduction zones. Earth's convecting mantle transports the former crust to the deep interior, and eventually back up to the surface. This work specifically seeks to understand the chemistry, structure, and dynamics of oceanic crust in Earth's lower mantle. Plate tectonics and thus subduction-currents carrying crust into the deep mantle are an ongoing process; thus better understanding the distribution of, the dynamics of, and chemistry of deeply transported crust uniquely provides a window into the chemical and dynamical evolution of Earth's mantle as a whole. Past work clearly establishes how the mantle might convect, viable deep mantle minerals, and that there are seismically detected heterogeneities. This work builds upon these ideas by seeking to connect them via studying a known input into the system of unique chemistry: the oceanic crust. This work has broad impact, since the mantle's evolution ultimately plays a role in the chemical and thermal evolution of the oceans and atmosphere. A multidisciplinary approach is adopted for this project, since (a) high pressure mineral physics in the diamond anvil cell can investigate the properties of former crust and sediments (e.g., melt) at conditions 1000's of km deep in Earth's mantle; (b) how former crust interacts with convective flow and structures, including deep compositional reservoirs, hot mantle plumes, and deep mantle chemistries can be explored with state-of-the-art numerical convection experiments; and (c) former oceanic crust may relate to structures observed with modern array seismology methods that have unknown mineralogy, including thin ultra low seismic wave speed zones at the bottom of the mantle, as well as massive continent-sized zones of low shear wave velocities beneath the Pacific and Atlantic Oceans. The multidisciplinary proposed work will include a strong co-mentoring approach among the team of PIs for the graduate student and postdoctoral researchers.

这个为期两年的研究项目着重于研究俯冲带上地球内部的海洋壳和构造板的命运。 地球令人信服的地幔将前面的外壳运到深内部，并最终恢复到表面。 这项工作专门旨在了解地球下地幔中海洋壳的化学，结构和动力学。板块构造，因此将硬皮带入深幔的俯冲流是一个持续的过程。因此，更好地理解了深层运输地壳的分布，动力学和化学的独特性，为整个地球地幔的化学和动态演化提供了一个窗口。过去的工作清楚地确定了地幔如何对流，可行的深层矿物质，并且存在地震探测的异质性。 这项工作以这些想法为基础，试图通过研究对独特化学系统的已知输入：海洋壳。这项工作产生了广泛的影响，因为地幔的演化最终在海洋和大气的化学和热演化中发挥了作用。该项目采用了多学科的方法，因为（a）钻石砧细胞中的高压矿物质物理学可以在地球深1000 km的条件下研究以前的地壳和沉积物（例如熔体）的性质； （b）如何通过最先进的数值对流实验来探索以前的外壳如何与对流流和结构相互作用，包括深层组成储层，热地幔羽和深层化学。 （c）以前的海洋壳可能与现代阵列地震学方法观察到的结构有关，这些方法具有未知的矿物学，包括地幔底部的薄超低地震波速区，以及大陆大小的大型大陆大小的区域，其低剪力波速度是太平洋和大西洋海洋下方。跨学科建议的工作将包括针对研究生和博士后研究人员的PI团队中强大的同事方法。