Nanoscale 3D quantitative imaging of 1.88 Ga Gunflint microfossils reveals novel insights into taphonomic and biogenic characters

Author(s):Show less -

Maldanis, L. ^{[1, 2, 3]} ; Hickman-Lewis, K. ^{[4, 5]} ; Verezhak, M. ^[6] ; Gueriau, P. ^{[7, 8]} ; Guizar-Sicairos, M. ^[6] ; Jaqueto, P. ^[9] ; Trindade, R. I. F. ^[9] ; Rossi, A. L. ^[10] ; Berenguer, F. ^[11] ; Westall, F. ^[4] ; Bertrand, L. ^{[7, 12]} ; Galante, D. ^{[1, 13]}

Affiliation:Show less -

^[1] Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Synchrotron Light Lab LNLS, Av Giuseppe Maximo Scolfaro 10000, BR-13083100 Campinas - Brazil

^[2] Univ Sao Paulo, Inst Phys Sao Carlos, Av Trabalhador Sao Carlense, BR-13566590 Sao Carlos - Brazil

^[3] UGA, CNRS, ISterre, Observ Sci Univers, CS 40700, F-38058 Grenoble - France

^[4] CNRS, Ctr Biophys Mol, Rue Charles Sadron, F-45071 Orleans - France

^[5] Univ Bologna, Dipartimento Sci Biol Geol & Ambientali BiGeA, Via Zamboni 67, I-40126 Bologna - Italy

^[6] Paul Scherrer Inst, Forschungsstr 111, CH-5232 Villigen - Switzerland

^[7] Univ Paris Saclay, CNRS, Minist Culture, UVSQ, IPANEMA, F-91192 St Aubin - France

^[8] Univ Lausanne, Inst Earth Sci ISTE, Lausanne - Switzerland

^[9] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, Dept Geophys, Rua Matao 1226, BR-05508090 Sao Paulo - Brazil

^[10] Brazilian Ctr Res Phys CBPF, R Dr Xavier Sigaud 150, BR-22290180 Rio De Janeiro - Brazil

^[11] Synchrotron Soleil, BP 48 St Aubin, F-91192 Gif Sur Yvette - France

^[12] Univ Paris Saclay, F-91190 St Aubin - France

^[13] Gueriau, P., Univ Lausanne, Inst Earth Sci ISTE, Lausanne, Switzerland.Maldanis, L., Brazilian Ctr Res Energy & Mat CNPEM, Brazilian Synchrotron Light Lab LNLS, Av Giuseppe Maximo Scolfaro 10000, BR-13083100 Campinas - Brazil

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 10, n. 1 MAY 18 2020.
• Web of Science Citations: 0

Abstract

Precambrian cellular remains frequently have simple morphologies, micrometric dimensions and are poorly preserved, imposing severe analytical and interpretational challenges, especially for irrefutable attestations of biogenicity. The 1.88 Ga Gunflint biota is a Precambrian microfossil assemblage with different types and qualities of preservation across its numerous geological localities and provides important insights into the Proterozoic biosphere and taphonomic processes. Here we use synchrotron-based ptychographic X-ray computed tomography to investigate well-preserved carbonaceous microfossils from the Schreiber Beach locality as well as poorly-preserved, iron-replaced fossil filaments from the Mink Mountain locality, Gunflint Formation. 3D nanoscale imaging with contrast based on electron density allowed us to assess the morphology and carbonaceous composition of different specimens and identify the minerals associated with their preservation based on retrieved mass densities. In the Mink Mountain filaments, the identification of mature kerogen and maghemite rather than the ubiquitously described hematite indicates an influence from biogenic organics on the local maturation of iron oxides through diagenesis. This non-destructive 3D approach to microfossil composition at the nanoscale within their geological context represents a powerful approach to assess the taphonomy and biogenicity of challenging or poorly preserved traces of early microbial life, and may be applied effectively to extraterrestrial samples returned from upcoming space missions. (AU)

• FAPESP's process: 15/21810-6 - Development and aplication of high resolution imaging techniques for morphological characterization of microfossils
• Grantee: Lara Maldanis Cerqueira Peres
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/25681-9 - Development and application of high-resolution imaging techniques for morphological and chemical characterization of microfossils
• Grantee: Lara Maldanis Cerqueira Peres
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• 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