Early Proterozoic microfossils and penecontemporaneous quartz cementation in the Sokoman Iron Formation, Canada

Abstract

Early Proterozoic microfossils from the Sokoman Iron Formation, northeastern Canada, are indistinguishable from those of the Gunflint Formation in both morphology and inferred community structure. The contemporaneity of the Sokoman assemblage with the Bitter Springs-like cyanobacteria of the Belcher Supergroup indicates that differences between the two major types of early Proterozoic microbiotas are primarily ecological and not temporal (evolutionary) in nature. In arenaceous iron formations, microfossils are restricted to peloids and are absent from pore-filling silica interpreted as cement. Cemented arenaceous intraclasts indicate that some of the silica was penecontemporaneous, and the abundance of minus-cement porosity in arenaceous iron formations demonstrates that early (pre-compaction) cementation was common.

Publisher

American Association for the Advancement of Science

Publication Date

1-1-1981

Publication Title

Science

Department

Geology

Document Type

Article

DOI

https://dx.doi.org/10.1126/science.211.4481.478

Language

English

Format

text

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