Formation of ferromanganese crusts and history of phosphatization in the Rio Grande Rise

Abstract

Little is known about the origin and evolution of minerals deposits of the Rio Grande Rise (RGR), one of the largest oceanic rises in the SW Atlantic Ocean. It hosts at least three types of marine mineral deposits - ferromanganese crusts, phosphorites, and ironstones - of which the first two may be of economic value. Two research cruises were carried to the RGR and we have collected and described many samples of these three types of marine mineral deposits; The PhD project to which this proposal is bound has already produced a large array of significant analytical data. However, it is fundamental to produce age dates based on isotopic and geochemical analytical techniques that are not available in Brazil, as well as to receive advice and training on data analyses closely to experienced researchers in the marine minerals field. For this, it is proposed a research internship at the United States Geological Survey under supervision of Dr. James Hein, who has worked on marine minerals for the past decades and a production of more than 500 papers and abstracts in the field. The work undertaken in the research internship will allow addressing key fundamental questions relevant to the origin and evolution of the mineral deposits on the RGR, as well as in part the history of RGR in general. This way, the proposed internship project will be of extreme importance to reach the main goals of the FAPESP Thematic Project Marine E-tech, which is to understand the formation of ferromanganese deposits in oceanic seamounts, especially in the RGR. (AU)