The distribution of platinum-group elements and Te, As, Bi, Sb and Se (TABS plus ) in the Parana Magmatic Province: Effects of crystal fractionation, sulfide segregation and magma degassing

Autor(es)

Mansur, Eduardo ^[1] ; Barnes, Sarah-Jane ^[1] ; Janasi, Valdecir ^[2] ; Henrique-Pinto, Renato ^[2] ; Alves, Adriana ^[2] ; Marteleto, Natasha Sarde ^[2]

Afiliação do(s) autor(es)

^[1] Univ Quebec Chicoutimi, Sci Terre, Chicoutimi, PQ G7H 2B1 - Canada

^[2] Univ Sao Paulo, Inst Geociencias, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: LITHOS; v. 400, NOV 1 2021.
• Citações Web of Science: 0

Resumo

The concentrations of Te, As, Bi, Sb and Se (TABS+) in magmas from large igneous provinces (LIPs) are of interest because these elements are important in the formation of platinum-group minerals (PGM) found in magmatic Ni-Cu platinum-group element (PGE) deposits. Furthermore, the TABS+ are volatile and hence they may be lost in degassing and have a role to play in the mass extinctions associated with LIPs events because these are mostly toxic elements. However, the concentrations of TABS+ in magmas from LIPs are not well documented due in part to the analytical difficulties and in part to the numerous processes that affect their distribution. We have determined the concentration of TABS+ and PGE in rocks from the Parana Magmatic Province (PMP) in order to assess the effects of fractional crystallization, sulfide segregation and magma degassing. Decrease in the Rh, Ru and Ir concentrations with Mg and Cr indicate that these elements behaved as compatible elements during crystal fractionation. Based on changes in the Cu/Pd sulfide saturation occurred in some cases resulting into a decrease in Pd and Pt. Arsenic and Sb behave as incompatible elements, whereas Se, Te and Bi show variable behaviour. Most lavas from the PMP display negative As, Se and Te anomalies on mantle-normalized patters coupled with Te/Cu, Se/Cu and As/Th and Sb/Th ratios lower than mantle values, which we attribute to loss of the TABS+ during degassing. (AU)

• Processo FAPESP: 19/22084-8 - A Província Magmática Paraná: petrogênese, cronologia e impacto ambiental do magmatismo toleítico, alcalino e silícico Cretáceo na Plataforma Brasileira
• Beneficiário: Valdecir de Assis Janasi
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 12/06082-6 - A província magmática Paraná-Etendeka no Brasil: relações temporais e petrológicas entre o magmatismo toleítico e alcalino e suas implicações geodinâmicas
• Beneficiário: Excelso Ruberti
• Modalidade de apoio: Auxílio à Pesquisa - Temático