Cryogenian glaciostatic and eustatic fluctuations and massive Marinoan-related deposition of Fe and Mn in the Urucum District, Brazil

Author(s):Show less -

Freitas, B. T. ^[1] ; Rudnitzki, I. D. ^[2] ; Morais, L. ^{[3, 4]} ; Campos, M. D. R. ^[1] ; Almeida, R. P. ^[4] ; Warren, V, L. ; Boggiani, P. C. ^[4] ; Caetano-Filho, S. ^[4] ; Bedoya-Rueda, C. ^[4] ; Babinski, M. ^[4] ; Fairchild, T. R. ^[4] ; Trindade, R. I. F. ^[3]

Affiliation

^[1] Univ Estadual Campinas, Fac Tecnol, BR-13484332 Limeira, SP - Brazil

^[2] Univ Fed Ouro Preto, Dept Geol, BR-35400000 Ouro Preto, MG - Brazil

^[3] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508090 Sao Paulo, SP - Brazil

^[4] Inst Geociencias, BR-05508080 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: GEOLOGY; v. 49, n. 12, p. 1478-1483, DEC 1 2021.
• Web of Science Citations: 0

Abstract

Global Neoproterozoic glaciations are related to extreme environmental changes and the reprise of iron formation in the rock record. However, the lack of narrow age constraints on Cryogenian successions bearing iron-formation deposits prevents correlation and understanding of these deposits on a global scale. Our new multiproxy data reveal a long Cryogenian record for the Jacadigo Group (Urucum District, Brazil) spanning the Sturtian and Marinoan ice ages. Deposition of the basal sequence of the Urucum Formation was influenced by Sturtian continental glaciation and was followed by a transgressive interglacial record of >600 m of carbonates that terminates in a glacioeustatic unconformity. Overlying this, there are up to 500 m of shale and sandstone interpreted as coeval to global Marinoan glacial advance. Glacial outwash delta deposits at the top of the formation correlate with diamictite-filled paleovalleys and are covered by massive Fe and Mn deposits of the Santa Cruz Formation and local carbonate. This second transgression is related to Marinoan deglaciation. Detrital zircon provenance supports glaciostatic control on Cryogenian sedimentary yield at the margins of the Amazon craton. These findings reveal the sedimentary response to two marked events of glacioeustatic incision and transgression, culminating in massive banded iron deposition during the Marinoan cryochron. (AU)

• FAPESP's process: 16/19736-5 - Quantitative approaches for big river deposits: integrated field geology and 3D photogrammetric models
• Grantee: Bernardo Tavares Freitas
• Support Opportunities: Regular Research Grants
• FAPESP's process: 17/22099-0 - Mechanisms of biomineralization and paleobiology of neoproterozoic eukaryotic microfossils from South Paraguay Belt
• Grantee: Luana Pereira Costa de Morais
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 16/06114-6 - The Neoproterozoic Earth System and the rise of biological complexity
• Grantee: Ricardo Ivan Ferreira da Trindade
• Support Opportunities: Research Projects - Thematic Grants