Diverse vase-shaped microfossils within a Cryogenian glacial setting in the Urucum Formation (Brazil)

Author(s):Show less -

Morais, L. ^{[1, 2]} ; Freitas, B. T. ^[3] ; Fairchild, T. R. ^[2] ; Toniolo, T. F. ^[2] ; Campos, M. D. R. ^[3] ; Prado, G. M. E. M. ^[2] ; Silva, P. A. S. ^[4] ; Rudnitzki, I. D. ^[5] ; Lahr, D. J. G. ^[6] ; Leme, J. M. ^[2] ; Philippot, P. ^{[1, 7]} ; Lopez, M. ^[7] ; Trindade, R. I. F. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, Dept Geophys, Rua Matao 1226, Cidade Univ, BR-05508900 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Geosci, Rua Lago 562, Cidade Univ, BR-05508080 Sao Paulo - Brazil

^[3] Univ Estadual Campinas, Sch Technol, Geol Lab, Rua Paschoal Marmo 1888, BR-13484332 Limeira - Brazil

^[4] Fed Univ Para, Inst Geosci, Cathodoluminescence Lab, Postgrad Program Geol & Geochem, Rua Augusto Correa S-N, BR-66075110 Belem, Para - Brazil

^[5] Fed Univ Ouro Preto DEGEO UFOP, Dept Geol, Morro Cruzeiro S-N, BR-35400000 Ouro Preto - Brazil

^[6] Univ Sao Paulo, Inst Biosci, Dept Zool, Rua Matao, Travessa 14, 101 Cidade Univ, BR-05508090 Sao Paulo - Brazil

^[7] Univ Montpellier, Geosci Montpellier, CNRS UMR 5243, Pl Eugene Bataillon, F-34095 Montpellier - France

• Document type: Journal article
• Source: Precambrian Research; v. 367, DEC 2021.
• Web of Science Citations: 0

Abstract

Vase-shaped microfossils (VSMs) attributed to testate amoebae occur globally in diverse assemblages in Tonian rocks. These microfossils have thus been considered a potential biostratigraphic tool, especially for the interval between 789 and 729 Ma. Here we report a diverse and well-preserved in situ VSM assemblage, including several taxa previously considered as Tonian, within glacially influenced deposits for which sedimentological data support a Cryogenian age. However, the more robust recent multi-proxy correlation proposed by Freitas et al. (2021) indicates a Marinoan age for the studied succession. Detrital zircon data provide a maximum depositional weighted mean age of 749 +/- 3 Ma for the VSM-bearing, organic-rich, fine-grained deposits within the Marinoan sequence in the Urucum Formation. Nine taxa are described from the fine-grained deposits in the upper Urucum Formation, Jacadigo Group, Brazil: Cycliocyrillium simplex, Bonniea dacruchares, Bonniea pytinaia, Bombycion micron, Limeta lageniformis, Palaeoarcella athanata, Trigonocyrillium horodyskii, Pakupaku kabin and cf. Taruma rata. The discovery of well-preserved in situ VSMs attributable to specific Tonian taxa within a Cryogenian succession challenges previous thinking that these organisms disappeared from marine ecosystems at the end of the Tonian. (AU)

• FAPESP's process: 15/16235-2 - The co-evolution of life and oxygen on early Earth: a South American perspective
• Grantee: Pascal Andre Marie Philippot
• Support Opportunities: Research Projects - SPEC Program
• 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
• FAPESP's process: 16/05937-9 - Comparative study of vase-shaped microfossils (VSMs) in collections at Harvard University and the University of California at Santa Barbara (Cambridge, MA; Santa Barbara, CA, USA)
• Grantee: Luana Pereira Costa de Morais
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• 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