First Comprehensive Sampling of the Shona and Discovery Seamount Chains, South Atlantic - Plume Versus Shallow Sources

Columbia University, New York NY

Investigators

Abstract

ABSTRACT - 07518437 (Class) Intellectual Merit: This research is part of a larger international collaboration to examine geological and geophysical phenomena of the seafloor and the phenomena beneath it in the South Atlantic in the area of the Shona and Discovery hotspots. Although the existence of Shona and Discovery mantle plumes has been suggested based solely on geochemical signatures measured in Mid-Ocean Ridge basalts, the verification of one or more mantle plumes has yet to be made. The presence of these are important because they form the basis of models of continental alkaline magmatism such as the South African diamond-bearing kimberlites and for the recycling and dispersal of subcontinental lithospheric mantle. Research will focus on the analysis of samples from dredged from the German Polarstern cruise to the Shona Ridge - Agulhas Ridge - Cape Rise and Discovery Seamount areas in the South Atlantic. The funded work will entail analyses of seafloor volcanic rocks for Sr-Nd-Hf-Pb isotopic compositions. These data will be integrated with major and trace element data and geophysical data from a multidisciplinary, international team of investigators. The integrated data set will be used to determine the existence of a long-lived Shona plume or, alternatively, a continental origin for the Shona and Discovery bathymetric anomalies. Broader impacts: Impacts of this work include international cross-disciplinary collaboration with Germany, The Netherlands, and South Africa. It will support a female career researcher and help train a graduate student from the University of Cape Town who will be trained in analytical methods and conduction of independent research. Funding also will help provide essential equipment to the isotope lab at Lamont Doherty Earth Observatory.