Impacts are usually described as catastrophic events with global effects and mass extinctions, as with the K/T boundary event. Life has been punctuated by impacts at several times during Earth's history, not least on the early Earth, when devastating impacts are believed to have sterilized the entire surface of the Earth.
In an astrobiological context, however, impacts have been suggested as events with substantial influence on the sustainability of a biosphere on a planetary body. This is due to the effects an impact may result in, such as extensive fracturing of the targeted bedrock and hydrothermal activity driven by heat from the impact melt which can potentially support a deep biosphere. These effects may be crucial for life on a planetary body that is otherwise uninhabitable.
In this project I investigate impact craters in Sweden, mainly at Lockne and Siljan, and study fossilized microorganisms preserved in paleo-hydrothermal mineralizations.
Sjöqvist, A.S.L., Lindgren, P., Sturkell, E.F.F., Hogmalm, K.J., Broman, C., Ivarsson, M., Lee, M.R. 2016. Shock metamorphism and hydrothermal alteration of mafic impact ejecta from the Lockne impact structure, Sweden. GFF, DOI: 10.1080/11035897.2016.1227361
Ivarsson, M., Broman, C., Sturkell, E., Ormö, J., Siljeström, S., van Zuilen, M., Bengtson, S. 2013. Fungal colonization of an Ordovician impact-induced hydrothermal system. Scientific Reports 3: 3487, DOI:10.1038/srep03487
Lindgren, P., Ivarsson, M., Neubeck, A., Broman, C., Henkel, H. and Holm, N.G. 2010. Putative fossil life in a hydrothermal system of the Dellen impact structure, Sweden. International Journal of Astrobiology 9: 137-146