6:15 PM - 7:30 PM
[BCG28-P15] Mineralogical and geochemical study of marine sedimentary rocks of Gunflint Formation(1.9 Ga), Ontario, Canada
Concentration patterns of Fe are different from lowermost to upper sections. Such change is corresponded to disappearance of BIF, thus decrease of Fe flux in shallow sediments. Compositions of kerogen were similar through the entire sections. However, a section which recorded Sudbury impact shows variable N/C ratios of kerogen. This may suggest that nitrogen cycle through atmosphere, hydrosphere and biosphere changed temporarily right after meteorite impact.