CSEDI Collaborative Research: Application of siderophile elements to mantle geodynamics

CSEDI合作研究：亲铁元素在地幔地球动力学中的应用

• 批准号: 1160656
• 负责人: Linda Elkins-Tanton
• 金额: $ 3.44万
• 依托单位: Carnegie Institution of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-15 至 2014-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1160656&HistoricalAwards=false
• 关键词: CSEDI; Collaborative; Research; Application; siderophile

We propose to conduct collaborative, synergistic research combining observations of siderophile element compositions with geodynamic modeling to study the evolution of elemental and isotopic heterogeneities in the mantle. Siderophile elements are those with a preference to enter metal rather than silicates, and are thus, elements that are largely concentrated in planetary cores. The objectives of this study will be to develop a better understanding of the global processes that led to the establishment of siderophile element abundances in the mantle, assess the extent of and possible mechanisms for the long-term preservation of the siderophile elemental and isotopic heterogeneities observed in the terrestrial rock record, and combine this information with geodynamic modeling to provide new insights to develop a better understanding of the formation and early chemical evolution of the Earth. In part, this project will be accomplished via study of the petrologic and chronologic extents of 182W isotopic anomalies in terrestrial systems using a newly-developed, high precision mass spectrometry technique. Ancient rocks, such as komatiites for which we have already identified isotopic anomalies, as well as modern rocks, such as MORB, oceanic peridotites, and ocean island basalts, will be examined as part of this task. Where necessary, complementary concentration and isotopic data for other elements, such as Os and Nd, will be generated. To better understand the causes and implications of the isotopic systematics revealed, we will test, via different geodynamic models, mechanisms for the formation and dispersal of the geochemical reservoirs with the appropriate characteristics. By tracking hafnium and tungsten in models of a range of possible early Earth states, then comparing model results with observations, we will be able to rule out some early Earth formation models and also better understand mantle mixing over the evolution of the Earth.

我们建议进行协作，协同研究，将铁质元素组成与地球动力学建模的观察结合在一起，以研究地幔中元素和同位素异质性的演变。铁粒元素是偏爱进入金属而不是硅酸盐的元素，因此，大部分集中在行星岩心上的元素。这项研究的目标将是对导致地幔中铁质元素丰度的全球过程有更好的理解，评估观察到的辅助元素和同位素异质性的长期保存的程度和可能机制的程度和机制。在地面岩石记录中，将这些信息与地球动力学建模相结合，以提供新的见解，以更好地了解地球的形成和早期化学演化。在某种程度上，该项目将通过研究陆地系统中182W同位素异常的岩石学和时间顺序进行研究来完成，并使用新开发的高精度质谱技术来完成。我们已经确定的同位素异常的古老岩石，例如，将作为此任务的一部分检查了同位素异常以及现代岩石，例如Morb，Oceanic Peridotites和Ocean Island Basalts。必要时，将生成其他元素（例如OS和ND）的互补浓度和同位素数据。为了更好地理解所揭示的同位素系统学的原因和含义，我们将通过不同的地球动力学模型，具有适当特征的地球化学储层的形成和分散的机制进行测试。通过在一系列可能的早期地球状态的模型中跟踪Hafnium和Tungsten，然后将模型结果与观察结果进行比较，我们将能够排除一些早期的地球形成模型，并更好地理解地球上的地幔混合。