Abstract

Huronian feldspathic sandstones 30 km north of Thessalon (the Morin Township area) rest noncomformably upon Archean rocks and are overlain by the Huronian Gowganda Formation. They contain uraniferous pyritic quartz-pebble orthoconglomerate, similar to the uraniferous conglomerate ore of the Elliot Lake – Blind River area. The sandstones also contain paraconglomerate units at several stratigraphic levels which are lithologically similar to the Ramsay Lake and Bruce Formations.Trends in Huronian stratigraphy on the North Shore of Lake Huron suggest that in the Morin Township area the Quirke Lake Group is absent and the McKim and Pecors Formations, which contain much argillite, are likely to be very thin or absent. Thus the feldspathic sandstones of the Morin Township area are assigned to the Matinenda and the Mississagi Formations. The most continuous paraconglomerate unit might be correlated with the Ramsay Lake Formation.Huronian feldspathic sandstones lying nonconformably upon Archean rocks 16 km northeast of Sault Ste Marie (the 'Soo Series') and 50 km north of Sudbury, have many features in common with the sequence of the Morin Township area. Stratigraphic subdivision of these two sequences and finer delimitation of potential uraniferous units may be aided by using paraconglomerates such as the Ramsay Lake Formation as marker units. Such subdivision however will be uncertain until the number, exact stratigraphic position and the areal continuity of these paraconglomerates can be assessed better.

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