Magmatic-hydrothermal fluids leaching older seafloor exhalative rocks to form the IOCG deposits of the Carajas Province, Brazil: Evidence from boron isotopes

Autor(es)

Coelho de Melo, Gustavo Henrique ^[1] ; Soares Monteiro, Lena Virginia ^[2] ; Hunger, Raphael Bianchi ^[3] ; Freitas Toledo, Poliana Iara ^[3] ; Xavier, Roberto Perez ^[3] ; Zhao, Xin-Fu ^[4] ; Su, Zhi-Kun ^[4] ; Natividade Moreto, Carolina Penteado ^[3] ; Goes Pereira de Jesus, Silvandira dos Santos ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Ouro Preto, Dept Geol, Morro Do Cruzeiro S-N, BR-35400000 Ouro Preto, MG - Brazil

^[2] Univ Sao Paulo, Inst Geosci, R Lago 562, BR-56205508 Sao Paulo, SP - Brazil

^[3] Univ Estadual Campinas, Inst Geosci, R Carlos Gomes 250, BR-13083855 Campinas, SP - Brazil

^[4] China Univ Geosci, Sch Earth Resources, State Key Lab Geol Proc & Mineral Resources, Wuhan 430074 - Peoples R China

• Tipo de documento: Artigo Científico
• Fonte: Precambrian Research; v. 365, OCT 2021.
• Citações Web of Science: 0

Resumo

The notable group of iron oxide-copper-gold (IOCG) deposits at the Carajas Province (Amazonian Craton, Brazil) contain remarkable copper reserves due to a complex Neoarchean metallogenetic evolution. The overlay of diachronic hydrothermal-mineralizing events is revealed by two clusters of boron isotope compositions of hydrothermal tourmaline obtained in IOCG deposits (Salobo, Igarape Bahia, GT-46, Grota Funda and Furnas) with (i) high delta B-11 (+8.2 to +17.2 parts per thousand) and (ii) low delta B-11 (+3.4 to +9.8 parts per thousand) values. The isotopically heavy boron signatures, recorded in tourmaline cores, are inherited from the volcano-sedimentary sequences of the ca. 2.76 Ga Itacaiunas Supergroup, which includes exhalative tourmaline and spilites formed in extensive exhalative systems prior to the IOCG formation. During the main IOCG event at ca. 2.55 Ga, the regional circulation of magmatic-hydrothermal boron-rich fluids originated tourmaline rims and new crystals with lower d11B values. We describe the critical role of an older volcano-sedimentary as a source for boron and likely metals leached by magmatic-hydrothermal fluids to form the IOCG deposits of the Carajas Province. (AU)

• Processo FAPESP: 16/13162-7 - Evolução geoquímica e isotópica de sistemas cupríferos neoarqueanos e paleoproterozoicos da Província Carajás, PA
• Beneficiário: Roberto Perez Xavier
• Modalidade de apoio: Auxílio à Pesquisa - Regular