Geochemical processes in the formation of carbonate crusts and ferromanganese oxides at the Rio Grande Rise (South Atlantic Ocean)

• Grant number: 22/02847-0
• Support Opportunities: Regular Research Grants
• Start date: August 01, 2022
• End date: July 31, 2024
• Field of knowledge: Physical Sciences and Mathematics - Oceanography - Geological Oceanography
• Principal Investigator: Christian Millo
• Grantee: Christian Millo
• Host Institution: Instituto Oceanográfico (IO). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated researchers: Luigi Jovane ; Paulo César Fonseca Giannini

Abstract

The Rio Grande Rise (RGR) is a wide oceanic elevation located ~1200 km to the east of Brazil and 2000 km to the west of the Mid-Atlantic Ridge. The RGR is of strategic importance for Brazil, because in 2015 the International Seabed Authority (ISA) and the Brazilian Companhia de Pesquisa de Recursos Minerais (CPRM) signed a contract for the exploration of seafloor minerals in the region. In 2018, two oceanographic cruises of IOUSP revealed extensive presence of carbonate crusts and ferromanganese (FeMn) crusts in the RGR. At places, the association of the two kinds of crusts was observed. This Project aims at: 1) Characterize the age, geochemistry, mineralogy, and texture of both carbonate and FeMn crusts; 2) Investigate their formation mechanisms, with emphasis in the formation of initial layers of FeMn oxides onto carbonate substrates; 3) Investigate the potential genetic relationship between carbonate and FeMn crusts. The samples for this study were collected during the scientific cruises of IOUSP in 2018, and are available at the Institute. Analytical work will be carried out at the IOUSP or in partner laboratories at USP. This Project pertains to an internationally relevant research line, rapidly developing in Brazil. The expected results are promising to improve our understanding of the formation mechanisms of deep-ocean minerals. (AU)