Tricks of nature from the ancient earth and early mars: chemical gardens generate biomorphs with high preservation potential
Author(s)
Hirsch, Solomon
McMahon, Sean
Najorka, Jens
Sephton, Mark A
Type
Journal Article
Abstract
Observations of morphology are commonly used to evaluate the biogenicity of terrestrial microfossils and could constitute a crucial line of evidence for extraterrestrial life-detection missions in the future. However, evaluating the origin of morphological features in the rock record can be problematic because naturally occurring abiotic structures can resemble biological morphologies, which may lead to false-positive detections of fossilised life. Iron-mineralised chemical gardens have been highlighted as potentially confounding abiotic structures because of their morphological and chemical resemblance to biomineralised filaments. Despite this, the potential for chemical garden structures to be preserved in the fossil record has not been thoroughly investigated. Here, we subjected abiotic iron-mineralised chemical garden structures to artificial maturation using hydrous pyrolysis, in order to evaluate their preservation potential. We found that these abiotic filaments were relatively resistant to degradation caused by maturation when compared with analogous biological material. Additionally, the transformation of ferrihydrite to crystalline iron oxides was found to be relatively inhibited, likely because of the influence of silica. These findings highlight the need for fossilised filamentous material to be distinguished from chemical garden structures before a biological origin can be confidently attributed, particularly when observed in significantly altered rocks.
Date Issued
2026-03-01
Date Acceptance
2026-04-06
Citation
Geobiology, 2026, 24 (2)
ISSN
1472-4677
Publisher
Wiley
Journal / Book Title
Geobiology
Volume
24
Issue
2
Copyright Statement
© 2026 The Author(s). Geobiology published by John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
License URL
Identifier
https://www.ncbi.nlm.nih.gov/pubmed/42014783
Subjects
Fossils
Mars
Earth, Planet
Exobiology
Ferric Compounds
Publication Status
Published
Coverage Spatial
England
Article Number
e70045
Date Publish Online
2026-04-21