Hf-Pb isotope and trace element constraints on the origin of the Jacupiranga Complex (Brazil): Insights into carbonatite genesis and multi-stage metasomatism of the lithospheric mantle

Author(s)

Chmyz, Luanna ^{[1, 2]} ; Arnaud, Nicolas ^[1] ; Biondi, Joao Carlos ^[2] ; Azzone, Rogerio Guitarrari ^[3] ; Bosch, Delphine ^[1]

Affiliation

^[1] CNRS, Geosci Montpellier, Pl Eugene bataillon, F-34090 Montpellier - France

^[2] Univ Fed Parana, Programa Posgrad Geol, Av Coronel Francisco Heraclito dos Santos 210, BR-81531970 Curitiba, Parana - Brazil

^[3] Univ Sao Paulo, Inst Geociencias, Rua Lago 562, BR-05508080 Sao Paulo - Brazil

• Document type: Journal article
• Source: GONDWANA RESEARCH; v. 71, p. 16-27, JUL 2019.
• Web of Science Citations: 1

Abstract

The Lower Cretaceous Jacupiranga complex, in the central-southeastern portion of the South American Platform, includes carbonatites in dose association with silicate rocks (i.e. strongly and mildly silica-undersaturated series). Here we document the first hafnium isotope data on the Jacupiranga complex, together with new trace element and Pb isotope compositions. Even though liquid immisdbility from a carbonated silicate melt has been proposed for the genesis of several Brazilian carbonatites, isotopic and geochemical (e.g., Ba/La ratios, lack of pronounced Zr-Hf and Nb-Ta decoupling) information argues against a petrogenetic relationship between Jacupiranga carbonatites and their associated silicate rocks. Thus, an origin by direct partial melting of the mantle is considered. The isotopic compositions of the investigated silicate samples are coherent with a heterogeneously enriched subcontinental lithospheric mantle (SCLM) source of rather complex evolution. At least two metasomatic processes are constrained: (1) a first enrichment event, presumably derived from slab-related fluids introduced into the SCLM during Neoproterozoic times, as indicated by consistently old T-DM ages and lamprophyre trace signatures, and (2) a Mesozoic carbonatite metasomatism episode of sub-lithospheric origin, as suggested by epsilon Nd-epsilon Hf values inside the width of the terrestrial array. The Jacupiranga parental magmas might thus derive by partial melting of distinct generations of metasomatic vein assemblages that were hybridized with garnet peridotite wall-rocks. (C) 2019 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 12/06082-6 - The Paraná-Etendeka magmatic province in Brazil: temporal and petrologic relationships between the tholeiitic and alkaline magmatism and geodynamic implications
• Grantee: Excelso Ruberti
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 17/03768-8 - Xenocryst and Antecryst compositional influence in basic to ultrabasic alkaline magmas
• Grantee: Rogério Guitarrari Azzone
• Support Opportunities: Regular Research Grants