Putative fossil life in a hydrothermal system of the Dellen impact structure, Sweden
2010 (English)In: International Journal of Astrobiology, ISSN 1473-5504, E-ISSN 1475-3006, Vol. 9, no 3, 137-146 p.Article in journal (Refereed) Published
Impact-generated hydrothermal systems are commonly proposed as good candidates for hosting primitive life on early Earth and Mars. However, evidence of fossil microbial colonization in impact-generated hydrothermal systems is rarely reported in the literature. Here we present the occurrence of putative fossil microorganisms in a hydrothermal system of the 89 Ma Dellen impact structure, Sweden. We found the putative fossilized microorganisms hosted in a fine-grained matrix of hydrothermal alteration minerals set in interlinked fractures of an impact breccia. The putative fossils appear as semi-straight to twirled filaments, with a thickness of 1-21 mu m, and a length between 10 and 100 mu m. They have an internal structure with segmentation, and branching of filaments occurs frequently. Their composition varies between an outer and an inner layer of a filament, where the inner layer is more iron rich. Our results indicate that hydrothermal systems in impact craters could potentially be capable of supporting microbial life. This could have played an important role for the evolution of life on early Earth and Mars.
Place, publisher, year, edition, pages
2010. Vol. 9, no 3, 137-146 p.
early Earth, early Mars, hydrothermal system, impact structure, microfossils
IdentifiersURN: urn:nbn:se:kth:diva-46638DOI: 10.1017/S147355041000011XISI: 000278918700001ScopusID: 2-s2.0-77954564047OAI: oai:DiVA.org:kth-46638DiVA: diva2:454896
QC 201111082011-11-082011-11-042011-11-08Bibliographically approved