830 Million Year Old Microorganisms In Primary Fluid Inclusions In Halit

Figure 3. Microorganisms in individual primary fluid inclusions in Browne For- mation (central Australia) halite from the Empress 1A core, at 1520.1 m core depth. (A) Brown algal cell, viewed in plane- transmitted light. (B) Clear prokaryotic cocci (p), orange algal cell (a), and organic compound halo (oc) around air bubble; plane transmitted light. (C) Plane transmitted light (C1) and UV-vis light (C2) images of a chain of yellow algal cells, clear cocci, and an air bubble with a halo of clear organic compound that fluoresce blue. (D) Plane transmitted light (D1) and UV-vis light (D2) images of clear prokaryotes, yellow algae, suspect organic compound halo, air bubble, and clear acci- dental daughter crystals; organics fluoresce white and gold.

Primary fluid inclusions in bedded halite from the 830-m.y.-old Browne Formation of
central Australia contain organic solids and liquids, as documented with transmitted light and ultraviolet-visible (UV-vis) petrography.

These objects are consistent in size, shape, and fluorescent response with cells of prokaryotes and eukaryotes and with organic compounds. This discovery shows that microorganisms from saline depositional environments can remain well preserved in halite for hundreds of millions of years and can be detected in situ with optical methods alone.

This study has implications for the search for life in both terrestrial and extraterrestrial chemical sedimentary rocks.

Full Paper: 830-million-year-old microorganisms in primary fluid inclusions in halite, Geology


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