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(Referência obtida automaticamente do Web of Science, por meio da informação sobre o financiamento pela FAPESP e o número do processo correspondente, incluída na publicação pelos autores.)

Tectono-sedimentary evolution of the Neoproterozoic BIF-bearing Jacadigo Group, SW-Brazil

Texto completo
Autor(es):
Freitas, Bernardo T. [1] ; Warren, Lucas V. [1] ; Boggiani, Paulo C. [1] ; De Almeida, Renato Paes [1] ; Piacentini, Thiago [2]
Número total de Autores: 5
Afiliação do(s) autor(es):
[1] Univ Sao Paulo, Inst Geociencias, BR-05508080 Sao Paulo - Brazil
[2] Univ Queensland, Sch Earth Sci, Brisbane, Qld 4072 - Australia
Número total de Afiliações: 2
Tipo de documento: Artigo Científico
Fonte: SEDIMENTARY GEOLOGY; v. 238, n. 1-2, p. 48-70, JUN 15 2011.
Citações Web of Science: 34
Resumo

The Jacadigo Group contains one of the largest sedimentary iron and associated manganese deposits of the Neoproterozoic. Despite its great relevance, no detailed sedimentological study concerning the unit has been carried out to date. Here we present detailed sedimentological data and interpretation on depositional systems, system tracts, external controls on basin evolution, basin configuration and regional tectonic setting of the Jacadigo Basin. Six depositional systems were recognized: (I) an alluvial fan system; (II) a siliciclastic lacustrine system; (III) a fan-delta system; (IV) a bedload-dominated river system; (V) an iron formation-dominated lacustrine or marine gulf system; and (VI) a rimmed carbonate platform system. The interpreted depositional systems are related to three tectonic system tracts. The first four depositional systems are mainly made of continental siliciclastics and refer to the rift initiation to early rift climax stage; the lake/gulf system corresponds to the mid to late rift climax stage and the carbonate platform represents the immediate to late post rift stage (Bocaina Formation deposits of the Ediacaran fossil-bearing Corumba Group). The spatial distribution of the depositional systems and associated paleocurrent patterns indicate a WNW-ESE orientation of the master fault zone related to the formation of the Jacadigo Basin. Thus, the iron formations of the Jacadigo Group were deposited in a starved waterbody related to maximum fault displacement and accommodation rates in a restricted continental rift basin. The Fe-Si-Mn source was probably related to hydrothermal plume activity that reached the basin through the fault system during maximum fault displacement phases. Our results also suggest a restricted tectono-sedimentary setting for the type section of the Puga Formation. The Jacadigo Group and the Puga Formation, usually interpreted as glacial deposits, are readdressed here as basin margin gravitational deposits with no necessary relation to glacial processes. (C) 2011 Elsevier B.V. All rights reserved. (AU)

Processo FAPESP: 06/50845-3 - Sedimentologia e estratigrafia do Grupo Jacadigo, maciço do urucum (MS)
Beneficiário:Bernardo Tavares Freitas
Linha de fomento: Bolsas no Brasil - Iniciação Científica
Processo FAPESP: 04/01233-0 - Evolução geológica da porção meridional da Faixa Paraguai (Neoproterozóico III)
Beneficiário:Paulo César Boggiani
Linha de fomento: Auxílio à Pesquisa - Regular