Astrobiology Update
Dr. Richard Léveillé, Visiting Fellow in astrobiology at the Canadian Space Agency.
It's a pleasure to be back for my second year at HMP - the landscapes, geology and biology in and around the Haughton Crater are truly amazing. I am currently focusing on two main projects of importance to astrobiology. Astrobiology is the science of the origin, the evolution, the distribution and the future of life in the Universe. By understanding life on Earth, especially in places like the Haughton Crater and Devon Island, we can learn about the diversity and resilience of life, which in turn helps us to explore for signs of life elsewhere (either past or present), such as on Mars.
The first question I am investigating is did impact-induced hydrothermal systems (i.e. hot springs created by the force of the impact) at Haughton support chemosynthetic microbial ecosystems? At places like Yellowstone, hot springs are inhabited by a diverse community of microbes that live off of the chemicals and gases in the hot water. Could have the hot springs at Haughton also supported such a community of chemistry-loving microbes? Since these hot springs have been inactive for many millions of years, the answer to this question lies in some unique rocks found in and around the crater. Back when these springs were active, the hot waters (groundwater heated by the force of the impact) deposited distinct minerals in cracks and voids in the host rocks (those that were impacted). These minerals include calcite, quartz, gypsum, pyrite ("fool's gold') and marcasite, as well as Fe-oxides. I have collected numerous samples of these hydrothermal deposits for further study back in the laboratory (see below). Of course, we know that many impacts have occurred on Mars – could these impacts have supported life there? This work will hopefully help answer this question.
The second question I am trying to answer is what is the nature and origin of Mars-like minerals in ancient lake sediments found in the Haughton Crater? After the impact, a lake was eventually formed within the crater and sediments were deposited. The lake is now long gone and only the sediments are left. Within these sediments are distinct reddish-orange crusts and nodules. These contain the minerals gypsum, Fe-oxides and Fe-sulphate, among others. These minerals are similar to those found at Meridiani Planum by the Mars Exploration Rover Opportunity. By understanding these minerals formed at Haughton, we may better understand those at Meridiani and other places on Mars. In particular, it is possible that chemistry-loving microbes may have helped to form the minerals at Haughton. Again, I have collected many samples to be studied back in the laboratory at CSA.
In general, evidence of chemistry-based microbes may include microfossils of the microbes, biominerals (e.g. minerals formed by microbes), isotopic signatures (e.g. distinct ratios of sulfur and iron isotopes), or organic biomolecules (e.g. distinct organic compounds used by chemistry-loving microbes). To investigate these biomarkers, I will be using electron microscopes, mass spectrometers, x-ray based instruments and other laboratory techniques. Hopefully, I will be able to answer the two questions posed above and contribute to better understanding on life on Earth, and possibly helping to search for evidence of life found in rocks on Mars.
A hydrothermal vug within the Haughton crater. The yellow mineral is Fe-sulphate (fibroferrite or jarosite). The shinny mineral behind the hammer head is Fe-sulfide (marcasite). The orange mineral is Fe-oxide (the rusted remains of Fe-bearing minerals). Photo HMP-2006 / R. Léveillé
Crusts of gypsum and Fe-oxides (reddish orange minerals below the pen) found in intra-crater lake sediments of the Haughton crater. The brownish gray sediment is part of the Haughton Formation. Photo HMP-2006 / R. Léveillé
