» Articles » PMID: 31723181

Organo-mineral Associations in Chert of the 3.5 Ga Mount Ada Basalt Raise Questions About the Origin of Organic Matter in Paleoarchean Hydrothermally Influenced Sediments

Overview
Journal Sci Rep
Specialty Science
Date 2019 Nov 15
PMID 31723181
Citations 1
Authors
Affiliations
Soon will be listed here.
Abstract

Hydrothermal and metamorphic processes could have abiotically produced organo-mineral associations displaying morphological and isotopic characteristics similar to those of fossilized microorganisms in ancient rocks, thereby leaving false-positive evidence for early life in the geological record. Recent studies revealed that geologically-induced alteration processes do not always completely obliterate all molecular information about the original organic precursors of ancient microfossils. Here, we report the molecular, geochemical, and mineralogical composition of organo-mineral associations in a chert sample from the ca. 3.47 billion-year-old (Ga) Mount Ada Basalt, in the Pilbara Craton, Western Australia. Our observations indicate that the molecular characteristics of carbonaceous matter are consistent with hydrothermally altered biological organics, although significantly distinct from that of organic microfossils discovered in a chert sample from the ca. 3.43 Ga Strelley Pool Formation in the same area. Alternatively, the presence of native metal alloys in the chert, previously believed to be unstable in such hydrothermally influenced environments, indicates strongly reducing conditions that were favorable for the abiotic formation of organic matter. Drawing definitive conclusions about the origin of most Paleoarchean organo-mineral associations therefore requires further characterization of a range of natural samples together with experimental simulations to constrain the molecular composition and geological fate of hydrothermally-generated condensed organics.

Citing Articles

Soft X-ray Fluorescence and Near-Edge Absorption Microscopy for Investigating Metabolic Features in Biological Systems: A Review.

Bonanni V, Gianoncelli A Int J Mol Sci. 2023; 24(4).

PMID: 36834632 PMC: 9960606. DOI: 10.3390/ijms24043220.

References
1.
Schiffbauer J, Wallace A, Hunter Jr J, Kowalewski M, Bodnar R, Xiao S . Thermally-induced structural and chemical alteration of organic-walled microfossils: an experimental approach to understanding fossil preservation in metasediments. Geobiology. 2012; 10(5):402-23. DOI: 10.1111/j.1472-4669.2012.00332.x. View

2.
Garcia-Ruiz J, Hyde S, Carnerup A, Christy A, Van Kranendonk M, Welham N . Self-assembled silica-carbonate structures and detection of ancient microfossils. Science. 2003; 302(5648):1194-7. DOI: 10.1126/science.1090163. View

3.
Rasmussen B, Fletcher I, Brocks J, Kilburn M . Reassessing the first appearance of eukaryotes and cyanobacteria. Nature. 2008; 455(7216):1101-4. DOI: 10.1038/nature07381. View

4.
Allwood A, Walter M, Kamber B, Marshall C, Burch I . Stromatolite reef from the Early Archaean era of Australia. Nature. 2006; 441(7094):714-8. DOI: 10.1038/nature04764. View

5.
Duda J, Van Kranendonk M, Thiel V, Ionescu D, Strauss H, Schafer N . A Rare Glimpse of Paleoarchean Life: Geobiology of an Exceptionally Preserved Microbial Mat Facies from the 3.4 Ga Strelley Pool Formation, Western Australia. PLoS One. 2016; 11(1):e0147629. PMC: 4726515. DOI: 10.1371/journal.pone.0147629. View