Volatile-Bearing Phases at High Pressures and Temperatures: Volatile Release and Retention in Earth's Mantle

高压和高温下的挥发物承载相：地幔中的挥发物释放和保留

• 批准号: 1215745
• 负责人: Quentin Williams
• 金额: $ 29.33万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-07-01 至 2017-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1215745&HistoricalAwards=false
• 关键词: Volatile; Bearing; Phases; Pressures; Temperatures

The amount of water retained at depth within the Earth, and particularly within Earth's mantle, is a topic of key importance for understanding (1) the genesis and long-term volume of Earth?s oceans; (2) the genesis of magmas within the deep interior of the Earth, and thus the occurrence of volcanism in subduction-related environments, such as the circum-Pacific ring-of-fire; and (3) the viscous behavior of the deep planet, and hence for how the mantle flows and plate tectonics occurs. By the same token, the retention of carbon dioxide within the deep Earth is of critical importance for not only how much carbon the planet retains, but also for how much carbon dioxide has been cycled between the surface and the interior (and vice-versa). This project is designed to probe the properties at the high pressures and temperatures of Earth?s interior of a range of minerals known to retain water or carbon dioxide at either subduction zone or deeper mantle conditions. It is oriented towards providing data that will constrain how much water and carbon dioxide is retained at depth through, for example, constraining the likely presence and abundance of water and carbon-containing minerals at depth (through their likely signature in seismic studies) and their geochemical behavior (through probing their stability and high-pressure phase transitions).Specifically, the volatile-bearing phases lawsonite, topaz, phlogopite, dolomite and phase D will be primarily targeted, as these represent major volatile-bearing phases within material that is subducted from the near-surface into the planet's interior. Both x-ray diffraction and spectroscopic probes will be utilized, and the focus will be on simultaneous high-pressure and high-temperature experiments-these will take advantage of both extant and recently augmented high-pressure, high-temperature capabilities. These studies build and expand on a broad suite of characterizations of hydrogen- and carbon-bearing phases on compression at 300 K conducted by the PI and collaborators. The results will provide new constraints on the bonding properties of water and carbon within minerals at high pressures and temperatures, as well as on the thermodynamic properties (and particularly the equations of state) of these materials.

地球深处，特别是地幔深处保留的水量，对于理解(1)地球的起源和长期体积是一个至关重要的话题。年代的海洋;(2)地球内部深部岩浆的成因，以及在与俯冲有关的环境（如环太平洋火山带）中火山活动的发生；(3)深层行星的粘性行为，从而解释地幔流动和板块构造是如何发生的。出于同样的原因，地球深处二氧化碳的保留不仅对地球保留了多少碳至关重要，而且对地表和内部（反之亦然）之间有多少二氧化碳进行了循环也至关重要。这个项目旨在探测地球在高压和高温下的特性。已知在俯冲带或更深的地幔条件下保留水或二氧化碳的一系列矿物的内部。它的目标是提供限制水和二氧化碳在深度保留多少的数据，例如，通过限制水和含碳矿物在深度的可能存在和丰度（通过它们在地震研究中的可能特征）以及它们的地球化学行为（通过探测它们的稳定性和高压相变）。具体来说，含挥发物相lawsonite， topaz, phloopite，白云石和D相将是主要的目标，因为这些代表了从近地表俯冲到地球内部的物质中的主要含挥发物相。x射线衍射和光谱探针都将被利用，重点是同时进行高压和高温实验——这些将利用现有的和最近增加的高压、高温能力。这些研究建立和扩展了由PI和合作者进行的300k压缩时含氢和含碳相的广泛特征。该结果将为高压和高温下矿物中水和碳的结合特性，以及这些材料的热力学特性（尤其是状态方程）提供新的约束。