Change search
ReferencesLink to record
Permanent link

Direct link
Ultrastructural heterogeneity of carbonaceous material in ancient cherts: investigating biosignature origin and preservation
Department of Earth Science and Centre for Geobiology, University of Bergen, Norway.
MAX IV Laboratory, Lund University, Sweden.
Tianjin Institute of Geology and Mineral Resources, CGS, China.
Swedish Museum of Natural History, Department of Paleobiology. Department of Geology, Lund University, Sweden.ORCID iD: 0000-0003-2987-5559
Show others and affiliations
2015 (English)In: Astrobiology, ISSN 1531-1074, E-ISSN 1557-8070, Vol. 15, no 10, 825-842 p.Article in journal (Refereed) Published
Abstract [en]

Opaline silica deposits on Mars may be good target sites where organic biosignatures could be preserved. Potential analogues on Earth are provided by ancient cherts containing carbonaceous material (CM) permineralized by silica. In this study, we investigated the ultrastructure and chemical characteristics of CM in the Rhynie chert (c. 410 Ma, UK), Bitter Springs Formation (c. 820 Ma, Australia), and Wumishan Formation (c. 1485 Ma, China). Raman spectroscopy indicates that the CM has experienced advanced diagenesis or lowgrade metamorphism at peak metamorphic temperatures of 150–350C. Raman mapping and micro-Fourier transform infrared (micro-FTIR) spectroscopy were used to document subcellular-scale variation in the CM of fossilized plants, fungi, prokaryotes, and carbonaceous stromatolites.

In the Rhynie chert, ultrastructural variation in the CM was found within individual fossils, while in coccoidal and filamentous microfossils of the Bitter Springs and formless CM of the Wumishan stromatolites ultrastructural variation was found between, not within, different microfossils. This heterogeneity cannot be explained by secondary geological processes but supports diverse carbonaceous precursors that experienced differential graphitization. Micro-FTIR analysis found that CM with lower structural order contains more straight carbon chains (has a lower R3/2 branching index) and that the structural order of eukaryotic CM is more heterogeneous than prokaryotic CM.

This study demonstrates how Raman spectroscopy combined with micro-FTIR can be used to investigate the origin and preservation of silica-permineralized organics. This approach has good capability for furthering our understanding of CM preserved in Precambrian cherts, and potential biosignatures in siliceous deposits on Mars. Key

Place, publisher, year, edition, pages
2015. Vol. 15, no 10, 825-842 p.
Keyword [en]
Rhynie chert; Bitter Springs Formation; Wumishan Formation; Raman spectroscopy; Micro-FTIR; Carbonaceous material; Fossil
National Category
Other Earth and Related Environmental Sciences
Research subject
Diversity of life; The changing Earth
URN: urn:nbn:se:nrm:diva-1391DOI: 0.1089/ast.2015.1298OAI: diva2:866695
Swedish Research CouncilKnut and Alice Wallenberg Foundation
Available from: 2015-11-03 Created: 2015-11-03Bibliographically approved

Open Access in DiVA

fulltext(1009 kB)47 downloads
File information
File name FULLTEXT01.pdfFile size 1009 kBChecksum SHA-512
Type fulltextMimetype application/pdf

Other links

Publisher's full text

Search in DiVA

By author/editor
Vajda, Vivi
By organisation
Department of Paleobiology
In the same journal
Other Earth and Related Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar
Total: 47 downloads
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 48 hits
ReferencesLink to record
Permanent link

Direct link