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Accueil > Publications > Recherche par années > Années 2000 > 2004

Schelble, RT ; Westall, F ; Allen, CC

Similar to 1.8 Ga iron-mineralized microblota from the Gunflint Iron Formation, Ontcario, Canada : implications for Mars

Advances in Space Research 33, 1268-1273

par Administrateur - publié le , mis à jour le

Abstract :

A similar to1.8 Ga banded-iron stromatolite from the Mink Mountain locality (PPRG 336) of the Gunflint Iron Formation, Ontario, Canada was investigated as an analogue to Martian hematite deposits which have the potential to contain fossilized Martian life. The stromatolitic sample was primarily composed of quartz (SiO2) with fractional amounts of hematite (Fe2O3), greenalite ((Fe,Mg)(3)Si2O5(OH)(2)), and minor amounts of stilpnomelane (K(Fe2+,Mg,Fe3+, Al)(8)(Si,Al)(12)(O,OH)(27) . 2H(2)O). Iron-bearing minerals were present within thin, discontinuous bands aligned roughly parallel. Octahedral pseudomorphs of hematite after magnetite occurred as localized elongate clusters, as well as on the outer rims of detrital oncolitic structures. Microcrystalline greenalite was present as a clay occurring in layers subparallel to the stromatolitic layering. Greenalite was observed in both the silica- and iron-rich layers, as well as within oncolitic structures. Irregular aggregates of radiating stilpnomelane needles extended into the silica matrix.