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Ultrastructural het...
Ultrastructural heterogeneity of carbonaceous material in ancient cherts: investigating biosignature origin and preservation
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- Qu, Yuangao (författare)
- Department of Earth Science and Centre for Geobiology, University of Bergen, Norway
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- Engdahl, Anders (författare)
- Lund University,Lunds universitet,MAX IV-laboratoriet,MAX IV Laboratory,MAX IV Laboratory, Lund University, Sweden
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- Zhu, Shixing (författare)
- Tianjin Institute of Geology and Mineral Resources, CGS, China
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- Vajda, Vivi (författare)
- Swedish Museum of Natural History,Lund University,Lunds universitet,Naturhistoriska riksmuseet,Enheten för paleobiologi,Department of Geology, Lund University, Sweden,Berggrundsgeologi,Geologiska institutionen,Naturvetenskapliga fakulteten,Lithosphere and Biosphere Science,Faculty of Science
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- McLoughlin, Nicola (författare)
- Department of Geology, Lund University, Sweden
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(creator_code:org_t)
- Mary Ann Liebert Inc, 2015
- 2015
- Engelska.
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Ingår i: Astrobiology. - : Mary Ann Liebert Inc. - 1531-1074 .- 1557-8070. ; 15:10, s. 825-842
- Relaterad länk:
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https://nrm.diva-por... (primary) (Raw object)
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http://dx.doi.org/10...
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http://nrm.diva-port...
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https://urn.kb.se/re...
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https://lup.lub.lu.s...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- 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
Ämnesord
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Annan geovetenskap och miljövetenskap (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Other Earth and Related Environmental Sciences (hsv//eng)
- NATURVETENSKAP -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)
- NATURAL SCIENCES -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)
Nyckelord
- Rhynie chert; Bitter Springs Formation; Wumishan Formation; Raman spectroscopy; Micro-FTIR; Carbonaceous material; Fossil
- Livets mångfald
- Diversity of life
- The changing Earth
- Den föränderliga jorden
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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