ASTROBIOLOGY INVESTIGATIONS IN AND AROUND THE HAUGHTON IMPACT STRUCTURE

Impact cratering is one of the most ubiquitous processes affecting planetary surfaces in the Solar System. On Mars, a rich record of impacts is preserved and impact craters have been highlighted for recent and future missions as important astrobiological targets. The Haughton Impact Structure, located on Devon Island, an uninhabited and largely non-vegetated island in the Canadian High Arctic, is one of the best-preserved impact craters on Earth. The geological (e.g., extensive outcropping, excellent preservation) and geographical (e.g. cold, dry, dusty) characteristics of the crater and its surroundings make the area an ideal analog field site for testing astrobiological concepts and hypotheses of relevance to Mars. As a result, a number of questions of direct relevance to astrobiology, and Mars in particular, have been or are currently being investigated in and around the Haughton impact structure:

- Can impact-induced hydrothermal systems support chemosynthetic microbial communities?

- How do impacts affect the fate of organic biomarkers in target rocks?

- What is the nature of post-impact lacustrine sediments and what geobiological record do they contain?

- How do impacts affect geological properties of target rocks, in turn influencing microhabitats for endolithic microorganisms?

- What biomarkers are preserved in carbonate-rich, cold-climate alteration (biomineralization?) crusts?

- What is the geochemical and microbiological relevance of iron- and sulfate-rich (including jarosite) Mars-like cold-climate alteration minerals?

- Can the molar ratios (O₂/Ar, N₂/Ar, O₂/N₂) of gases entrapped in segregated ground-ice be used to identify microbial processes operating in the subsurface?

Results from these investigations will help to plan and design future missions and instruments, as well as to select target sites for future exploration of Mars. The Haughton Impact Structure and its surroundings offer a wealth of scientific opportunities relevant to Mars exploration and astrobiology. In light of these opportunities, a long-term, multi-disciplinary, and collaborative research program is warranted.