From mantle geodynamics to environmental processes: a geochemical perspective

从地幔地球动力学到环境过程：地球化学视角

• 批准号: 249476-2013
• 负责人: Weis, Dominique
• 金额: $ 4.88万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=634013
• 关键词: mantle; geodynamics; environmental; processes; geochemical

Modern geochemistry is concerned with quantifying and explaining the transfer of elements within and between the different major geological reservoirs of the Earth, including the mantle, the crust, the oceans, and the atmosphere. Geochemistry provides answers and tools for the fundamental understanding of our planet, including the environment, global change, resources, human health and natural hazards. Such research requires precise analysis of isotopic ratios and elemental concentrations in rocks, minerals, water, or organic matter. Multiple collector inductively coupled plasma mass spectrometers dramatically expand the potential isotopic systems that can be measured and allow for unprecedented sensitivity and precision. I propose to investigate three main themes of geochemical applications: 1) Earth's mantle and solid earth, 2) environmental impact, and 3) analytical developments in mass spectrometry. As the Earth's deep interior cannot be sampled directly, geochemists rely on analyzing basalts to infer the composition of the mantle. I propose to study two of the largest modern mantle plumes (Hawaii and Kerguelen) that originate in the deep mantle and, as well as Cascade Arc volcanoes and sediments to model the amount of recycling into the mantle. The results of this research will contribute to the global understanding of the composition and distribution of components in the mantle and their variation over geologic time. In the environmental theme, I will use heavy stable isotope systems (Cd, Zn, Si coupled with Pb) to investigate element cycling and metal pollution in marine and terrestrial systems. This work will increase our understanding of ancient climates and oceanographic conditions and has implications for British Columbia fisheries and aquaculture industry. Research within the third theme includes systematic studies to characterize reference materials and identify problematic matrix effects during mass spectrometry. This work will lead to an invaluable reference database and methodology for the scientific community. The overall objective of the proposed 5-year research program is to evaluate the geochemical evolution of our planet and its environment through the use of new analytical possibilities in isotopic geochemistry.

现代地球化学关注的是量化和解释地球不同主要地质储层（包括地幔，地壳，海洋和大气）内部和之间的元素转移。地球化学为我们对地球的基本理解提供了答案和工具，包括环境，全球变化，资源，人类健康和自然灾害。这类研究需要对岩石、矿物、水或有机物中的同位素比率和元素浓度进行精确分析。多接收电感耦合等离子体质谱仪极大地扩展了可测量的潜在同位素系统，并实现了前所未有的灵敏度和精度。我建议研究地球化学应用的三个主要主题：1）地幔和固体地球，2）环境影响，3）质谱分析的发展。由于地球内部深处无法直接取样，地球化学家依靠分析玄武岩来推断地幔的成分。我建议研究两个最大的现代地幔柱（夏威夷和Kerguelen），起源于深地幔，以及级联弧火山和沉积物模型的量回收到地幔。这一研究成果将有助于全球对地幔成分组成、分布及其随地质时期变化的认识。在环境主题中，我将使用重稳定同位素系统（Cd，Zn，Si与Pb）来研究海洋和陆地系统中的元素循环和金属污染。这项工作将增加我们对古代气候和海洋条件的了解，并对不列颠哥伦比亚省渔业和水产养殖业产生影响。第三个主题的研究包括系统的研究，以表征参比物质，并确定在质谱分析有问题的基质效应。这项工作将为科学界提供宝贵的参考数据库和方法。拟议的5年研究方案的总体目标是通过使用同位素地球化学中新的分析可能性来评估我们星球及其环境的地球化学演变。