Ancient microorganisms found in halite may have implications for search for life

The Browne Formation of central Australia contains primary fluid in bedded halite that is documented with transmitted light and UV-vis. These objects are consistent in size, shape, and fluorescent response to cells of prokaryotes and algae. The discovery shows that the organisms from the depositional environments can be detected in situ with optical methods alone. This study has implications for the search for life in both extraterrestrial and terrestrial chemical sedimentary rocks.

As halite crystals grow, they trap parent water in primary fluid inclusions. In addition to trapping parent waters, they can also trap any particles that were in the water near the crystal face. There are tiny crystals of evaporite minerals. The presence of prokaryotic and eukaryotic organisms and organic compounds has been documented in previous studies.

The study used non-destructive, optical techniques to identify and document organic material in primary fluid inclusions. The Geological Survey of Western Australia gave access to core samples from the Neoproterozoic Browne Formation.

The halite was well preserved and allowed them to examine it. They used light transmitted and UV-visible light to identify primary fluid inclusions. Solids trapped in fluid inclusions were consistent with prokaryotic and eukaryotic cells, and with organic compounds, based on their size, shape, and fluorescent response to UV-visible light.

The study reinforces the utility of non-destructive optical methods as a first step. The age of fluid inclusions is dependent on the context of the fluid inclusions, which represent original parent waters. Micro organisms can be preserved in fluid inclusions in halite for millions of years, and this study suggests that similar biosignatures may be able to be detected in the chemical samples from Mars.

More information: Sara I. Schreder-Gomes et al, 830-million-year-old microorganisms in primary fluid inclusions in halite, Geology (2022). DOI: 10.1130/G49957.1 Journal information: Geology Citation: Ancient microorganisms found in halite may have implications for search for life (2022, May 11) retrieved 11 May 2022 from https://phys.org/news/2022-05-ancient-microorganisms-halite-implications-life.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. The content is provided for information purposes only.