Collaborative Research: A High-Resolution, Multi-Isotopic Study of Upper Mantle Heterogeneity Beneath the Southeast Indian Ridge

众所周知，地幔的融化条件在地理上是不同的，这与地幔温度和成分的不同有关。然而，这些变化与沿大洋中脊喷发的熔岩成分之间的关系尚不为人所知。这项研究重点分析了印度洋东南印度洋海脊1200公里海脊上130个地点的一组独特的密集玄武岩样品的化学异同。目标是确定海底熔岩的空间和时间变化，达到对这一部分海底前所未有的程度，并将趋势与下伏的地幔过程联系起来。2009年在该地区进行的一次国际考察中收集的样品将被分析为氦、铅、氢和锶的同位素。40个样品还将被分析氦和氦的同位素以及二氧化碳。这项工作的数据将与从事样品研究的国际科学家小组提供的补充地球化学数据(即常量元素和微量元素)结合起来。这项工作的更广泛影响包括与德国和法国科学家的国际合作，以及研究和教育的整合。该项目涉及方法开发，这将促进分析的实验室间校准，并为科学建立基础设施。

It is well known that there are geographic variations in the melting conditions in Earth's mantle and that these are tied to differences in mantle temperature and composition. How these variations relate to the composition of lavas erupted along mid-ocean ridges, however, is not well known. This research focuses on analyzing the chemical similarities and differences in a unique set of closely spaced samples of basalt from 130 localities along 1200 km of ridge crest of the Southeast Indian Ridge in the Indian Ocean. Goals are to determine the spatial and temporal variation of seafloor lavas to a degree that is unprecedented for this part of the seafloor and relate the trends to underlying mantle processes. Samples that are already in-hand and were collected on an international expedition to the area in 2009 will be analyzed for the isotopes of He, Pb, Hf, and Sr. Forty samples will also be analyzed for He and He isotopes and for CO2. Data from this work will be combined with complementary geochemical data (i.e., major and trace elements) from an international team of scientists working on the samples. Broader impacts of the work include international collaboration with German and French scientists and the integration of research and education. The project involves method development which will foster inter-laboratory calibration of analyses and builds infrastructure for science.