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.
