Questions of correlation across the Grenville Front east of Sudbury, Ontario

Intensely deformed and highly metamorphosed sedimentary and mafic igneous rocks southeast of the Grenville Front in the Sudbury area contrast strongly with the relatively simply folded, low-grade Huronian Supergroup and associated mafic intrusions in the adjacent Southern Province. Relict stratigraphy on the Grenville side of the front does not appear to correlate with any part of the well-known Huronian succession. It seems likely, however, that the mafic meta-igneous rocks are equivalent to anorthositic gabbro intrusions which occur at the base of the Huronian, and to Nipissing gabbro which intrudes it. If so, the metasedimentary rocks may represent distal facies of the Huronian Supergroup that have been tectonically transported northwestward during Grenvillian or earlier orogeny, or both.