9404617 Klein This research proposal centers on two unique types of Precambrian iron-formations in Brazil. The first is the iron and manganese region of Urucum which is of Late Proterozoic age. The second, of Archean age, is in the Serra dos Carajas region of Brazil and is considered the largest Archean deposit of high-grade iron ore in the world. These two iron-formations have been selected for detailed geologic, petrologic and geochemical studies (major elements, REE, total organic carbon, and C and S isotopics where appropriate). This is in full cooperation with Professor Eduardo A. Ladeira of the Federal University of Minas Gerais in Belo Horizonte and several of the Brazilian mining companies. Results from these studies will allow for better constraints in global geochemical models of evolution of the ocean and atmosphere in Precambrian time.
