The Schreiber-Marathon archean greenstone belt forms a part of the Shebandowan-Wawa Subprovince of the Superior structural Province of the Canadian shield. This thesis focuses on the eastern portion of the Schreiber-Marathon greenstone belt.
Bedrock in this area can be broadly divided into rocks of the Playter Harbour and Heron Bay supracrustal Groups. The Playter Harbour Group is composed predominantly of high-iron tholeiitic basalts and metasedimentary rocks primarily of volcanogenic origin. The Heron Bay Group includes calc-alkalic pyroclastic rocks of variable composition, high-iron tholeiitic basalts, and metasedimentary rocks of diverse origin.
The supracrustal rocks of both groups form east-west trending sequences which are intruded by a number of archean plutons and proterozoic sills and dykes. Regionally, the supracrustal rocks appear to conform closely to the contacts of extensive gneissic complexes of archean age.
Metamorphic grade is typically greenschist facies, however, amphibolite facies assemblages occur locally.
The regional structure of the rocks is complex and with the data available at present, open to a variety of interpretations. Evidence of widespread, large scale brittle and ductile deformation can be seen throughout the belt. In outcrop, the structures are highly diverse, often complex, and in many cases deformation is of such a magnitude as to obscure the original nature of the rocks.