Microbial Trace Fossils in Impact Glass

Enigmatic tubular features in impact glass

Authors:

Sapers et al

Abstract:

We describe the first putative microbial trace fossils hosted in meteorite impact glass. We conducted optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, and Fourier transform infrared spectroscopy on postimpact tubular features hosted in impact glasses from the Ries impact structure (Germany). The morphologies of the tubules are inconsistent with known mineralogical crystallization mechanisms, and combined with evidence of organic molecules suggest that these tubules cannot be formed through purely abiotic processes. The simplest and most consistent explanation of the data is that biological activity played a role in the formation of the tubular textures in the Ries glasses, likely during postimpact hydrothermal activity. As impact glass is a ubiquitous substrate on rocky bodies throughout the Solar System and likely common on the early Earth, the preservation of biological activity in impact glass has significant astrobiological implications for life on early Earth as well as for the search for life on other planets.