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

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，这是地幔和地壳之间全球地球化学循环的一个基本但目前缺乏约束的方面。本研究在不同的洋中脊扩张中心环境下研究了轴上和轴外火山作用之间的地球化学关系，试图发展一种集成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大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检查四个研究得很好的大洋中脊(东太平洋隆起、冰岛、加拉帕戈斯和胡安德富卡海脊)的地球化学，以预测产生离轴熔融所需的融化程度和深度，并将这些预测与地幔物理上现实的起源联系起来。为了建立更完整的离轴地球化学变化的地球化学记录，将分析东太平洋隆起附近20个海山的样品，以确定作为岩浆和岩浆分异过程指示器的锶、钕和铅的放射性成因等值线。一个主要的研究目标是开发强大的一维和二维模型，以确定是否存在全球一致的离轴过程，这些过程支撑着大洋中脊下的地幔融化。这项工作的更广泛影响包括从科学界代表性不足的群体发展博士后职业生涯，以及通过佛罗里达州当地的一家博物馆进行公众宣传。更广泛的影响还包括与一名英国科学家的国际合作，博士后在合作者的实验室里度过了一段时间，并接受了最先进的地球化学分析技术和地球动力学建模方面的交叉培训。

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.