An integrated geochemical and geodynamical approach to the origin of off-axis melt production at a range of mid-ocean ridge settings

综合地球化学和地球动力学方法来研究一系列洋中脊环境中离轴熔体产生的起源

• 批准号: 1233863
• 负责人: Rachel Walters
• 金额: $ 19.4万
• 依托单位: University of Florida
• 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: 2012-09-15 至 2016-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1233863&HistoricalAwards=false
• 关键词: integrated; geochemical; geodynamical; approach; origin

Understanding how ocean crust is created and its how melts of different chemistry are created is an essential but presently poorly constrained aspect of global geochemical cycling between the mantle and crust. This research investigates the geochemical relationship between on- and off-axis volcanism at a variety of mid-ocean ridge spreading center settings to try and develop an integrated dynamic geochemical and geophysical modeling approach to better understand the interaction of mantle heterogeneities with the mid-ocean ridge system. A key component of this work will be to examine the geochemistry of four well-studied mid-ocean ridges (East Pacific Rise, Iceland, Galapagos, and the Juan de Fuca Ridge) to predict the degree and depth of melting required to produce off-axis melts and relate these predictions to physically realistic origins in the mantle. To create a more complete geochemical record of off-axis geochemical variation, samples from 20 seamounts near the East Pacific Rise will be analyzed for the radiogenis isotoes of Sr, Nd, and Pb, which are indicators of magmatic and magma differentiation processes. A major reserach goal is to develop robust one and two dimensional models to determine whether or not there are globally consistent off-axis processes that underpin mantle melting beneath mid-ocean ridges. The broader impacts of the work include developing the career of a postdoc from a group under-represented in the sciences and public outreach through a local Florida museum. Broader impacts also include international collaboration with a UK scientist, with the postdoc spending time in the collaborator's laboratory and being cross-trained in state-of the art geochemical analytical techniques and geodynamical modeling.

了解洋壳是如何形成的，以及不同化学成分的熔体是如何形成的，是地幔和地壳之间全球地球化学循环的一个重要方面，但目前还没有受到很好的限制。 本研究探讨了洋中脊扩张中心的轴上和轴外火山活动之间的地球化学关系，试图开发一种综合的动态地球化学和地球物理模拟方法，以更好地了解地幔非均质性与洋中脊系统的相互作用。这项工作的一个关键组成部分将是审查四个经过充分研究的洋中脊（东太平洋海隆、冰岛、加拉帕戈斯和胡安·德富卡海岭）的地球化学，以预测产生离轴熔融所需的熔融程度和深度，并将这些预测与地幔中实际存在的起源联系起来。为了建立一个更完整的地球化学记录的离轴地球化学变化，样品从20个海山附近的东太平洋隆起将进行分析的Sr，Nd和Pb的放射性同位素，这是岩浆和岩浆分异过程的指标。一个主要的研究目标是开发强大的一维和二维模型，以确定是否有全球一致的离轴过程，支持地幔熔融下洋中脊。这项工作更广泛的影响包括发展科学领域代表性不足的群体的博士后职业生涯，以及通过当地的佛罗里达博物馆进行公众宣传。更广泛的影响还包括与英国科学家的国际合作，博士后在合作者的实验室里度过时间，并在最先进的地球化学分析技术和地球动力学建模方面接受交叉培训。