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Carbonaceous biosignatures of the earliest putative macroscopic multicellular eukaryotes from 1630 Ma Tuanshanzi Formation, north China

Qu, Yuangao; Zhu, Shixing; Whitehouse, Martin; Engdahl, Anders LU and McLoughlin, Nicola (2018) In Precambrian Research 304. p.99-109
Abstract

The Paleo- and Mesoproterozoic fossil record of multicellular eukaryotes is scarce but extremely important in studying the evolution of life in the Precambrian Era. Typically, fossils heralded as ‘multicellular eukaryotes’ that are older than the Ediacaran are met with controversy. To confront such debates, we investigate the chemical, isotopic, and molecular structural characteristics of organic matter from carbonaceous compressions in the 1630 Ma Tuanshanzi Formation in northern China, some of the earliest putative macroscopic multicellular eukaryote fossils (Zhu and Chen, 1995). The large-size and relative complexity of these fossils and similar remains from the 1.56 Ga Gaoyuzhuang Formation have led to their interpretation as... (More)

The Paleo- and Mesoproterozoic fossil record of multicellular eukaryotes is scarce but extremely important in studying the evolution of life in the Precambrian Era. Typically, fossils heralded as ‘multicellular eukaryotes’ that are older than the Ediacaran are met with controversy. To confront such debates, we investigate the chemical, isotopic, and molecular structural characteristics of organic matter from carbonaceous compressions in the 1630 Ma Tuanshanzi Formation in northern China, some of the earliest putative macroscopic multicellular eukaryote fossils (Zhu and Chen, 1995). The large-size and relative complexity of these fossils and similar remains from the 1.56 Ga Gaoyuzhuang Formation have led to their interpretation as eukaryotes. Raman spectral parameters give an estimated peak-metamorphic temperature TMax in the range of 202–286 °C, confirming the good preservation of the organic remains. Two-dimensional Raman maps of the carbonaceous compressions show ultrastructural variations that suggest diverse subcellular compounds being consistent with multicellular eukaryotes. The organic matter has carbon isotopic composition δ13Corg-SIMS between −45.3 and −32.2‰, and a branching index of carbon chain measured by the micro-FTIR spectral parameter R3/2 between 0.17 and 0.31. Together with their large-size and morphology, the isotopic, geochemical and ultrastructural data supports an interpretation of the Tuanshanzi Formation carbonaceous compressions as derived from phototrophic, multicellular eukaryotic algae. Our data support the early evolution of macroscopic multicellular eukaryotes in the sulfidic and low-oxygen conditions that prevailed in the Paleo- and Mesoproterozoic oceans.

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organization
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type
Contribution to journal
publication status
published
subject
keywords
Carbonaceous compression, Macroscopic eukaryote, Organic matter, Tuanshanzi Formation
in
Precambrian Research
volume
304
pages
11 pages
publisher
Elsevier
external identifiers
  • scopus:85034601512
ISSN
0301-9268
DOI
10.1016/j.precamres.2017.11.004
language
English
LU publication?
yes
id
2ec91a2c-0732-4d34-9c63-0f405a33ccc5
date added to LUP
2017-12-07 12:28:33
date last changed
2018-05-29 10:23:24
@article{2ec91a2c-0732-4d34-9c63-0f405a33ccc5,
  abstract     = {<p>The Paleo- and Mesoproterozoic fossil record of multicellular eukaryotes is scarce but extremely important in studying the evolution of life in the Precambrian Era. Typically, fossils heralded as ‘multicellular eukaryotes’ that are older than the Ediacaran are met with controversy. To confront such debates, we investigate the chemical, isotopic, and molecular structural characteristics of organic matter from carbonaceous compressions in the 1630 Ma Tuanshanzi Formation in northern China, some of the earliest putative macroscopic multicellular eukaryote fossils (Zhu and Chen, 1995). The large-size and relative complexity of these fossils and similar remains from the 1.56 Ga Gaoyuzhuang Formation have led to their interpretation as eukaryotes. Raman spectral parameters give an estimated peak-metamorphic temperature T<sub>Max</sub> in the range of 202–286 °C, confirming the good preservation of the organic remains. Two-dimensional Raman maps of the carbonaceous compressions show ultrastructural variations that suggest diverse subcellular compounds being consistent with multicellular eukaryotes. The organic matter has carbon isotopic composition δ<sup>13</sup>C<sub>org-SIMS</sub> between −45.3 and −32.2‰, and a branching index of carbon chain measured by the micro-FTIR spectral parameter R<sub>3/2</sub> between 0.17 and 0.31. Together with their large-size and morphology, the isotopic, geochemical and ultrastructural data supports an interpretation of the Tuanshanzi Formation carbonaceous compressions as derived from phototrophic, multicellular eukaryotic algae. Our data support the early evolution of macroscopic multicellular eukaryotes in the sulfidic and low-oxygen conditions that prevailed in the Paleo- and Mesoproterozoic oceans.</p>},
  author       = {Qu, Yuangao and Zhu, Shixing and Whitehouse, Martin and Engdahl, Anders and McLoughlin, Nicola},
  issn         = {0301-9268},
  keyword      = {Carbonaceous compression,Macroscopic eukaryote,Organic matter,Tuanshanzi Formation},
  language     = {eng},
  month        = {01},
  pages        = {99--109},
  publisher    = {Elsevier},
  series       = {Precambrian Research},
  title        = {Carbonaceous biosignatures of the earliest putative macroscopic multicellular eukaryotes from 1630 Ma Tuanshanzi Formation, north China},
  url          = {http://dx.doi.org/10.1016/j.precamres.2017.11.004},
  volume       = {304},
  year         = {2018},
}