The major early Proterozoic sedimentary iron and manganese deposits and their tectonic setting

Abstract

The recognition of Wilson cycle plate subduction in the early Proterozoic and the proposed amalgamation of a Proterozoic supercontinent from 2000 to 1800 Ma offers new insight into the tectonic setting of the large sedimentary basins of this age, which host the vast bulk of the world9s resources of iron and manganese in the very large Superior-type banded iron-formations. A reconstruction of the early Proterozoic microplates before amalgamation of Piper9s Proterozoic supercontinent shows that most of the major basins with Superior-type iron-manganese-formations have formed in a trailing margin tectonic setting. This tectonic setting is consistent with the favored geologic model in which the large iron and manganese deposits form on shallow continental margin shelves. The laterally continuous banding of these deposits also supports a stable tectonic setting.