We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
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.
- Authors
Alleon, Julien; Flannery, David T.; Ferralis, Nicola; Williford, Kenneth H.; Zhang, Yong; Schuessler, Jan A.; Summons, Roger E.
- 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.
- Subjects
PALEOARCHAEAN; MARINE sediments; FOSSIL microorganisms; ALLOYS; ANALYTICAL geochemistry
- Publication
Scientific Reports, 2019, Vol 9, Issue 1, pN.PAG
- ISSN
2045-2322
- Publication type
Article
- DOI
10.1038/s41598-019-53272-5