Date of Award
Dr. C.G. Winder
The Adair Marble Quarry is located 14 kilometres North of the Town of Wiarton on the East side of the Bruce Peninsula. This area is on the eastern margin of the Michigan Basin and the Middle Silurian dolostone extracted at the quarry is part of the concentric belts of Paleozoic formations that ring the Basin. The regional structure of the area is related to the Algonquin Arch, a basement feature attributed to progressive compressional and extensional stresses that are also responsible for the joint and fracture systems of the area. The present surface physiography was modified by the Wisconsin glaciation and post-glacial hydrology has produced an extensive karst system. The quarry has been operated at the present location by the Arriscraft Corporation of Cambridge, Ontario since 1979. Dolostone of the Wiarton Member of the Amabel Formation is currently extracted at the quarry. Approximately 6 metres below the present quarry surface the Wiarton Member grades into the Transition Zone between the Wiarton and Colpoy Bay Members. Differences occur between these two units and also within each unit. The Wiarton Member is typically a medium-grained , porous, blue-grey mottled, light grey and white dolostone while the Transition Zone Beds are fine-grained to dense, dark blue-grey mottled, buff to buff-grey dolostone. The mineralogy is essentially constant between the units and consists predominately of dolomite with cal cite, chalcedony, clay minerals, organic material and metallic minerals. An increase in chalcedony, clay minerals and metallic minerals occurs at depth. A change in the type of stylolites occurs with the individual, well defined type in the Wiarton Beds replaced by swarms of microstylolites in the Transition Zone Beds. The variations noted between the units can be attributed to a change in the original carbonate. The Wiarton Member represents a shallow, low energy shelf facies while the Transition Zone Beds are a more basinal facies. Within the units variations in the amount and type of mottling are due to the organic content of the rock and the type of dolomitization. Areas of higher organic content have a darker colour and are comprised of incipient dolomicrite formed through a sulphate reduction process. Lighter coloured and white areas are comprised of a dolomite mosaic formed through freshwater/seawater mixing. The one constant feature of the rock is the presence of sub-horizontal fractures. These fractures can be accurately mapped by ground probing radar to a depth of 10 metres as an aid to quarry planning. All of these features vary in a random fashion and the characteristics of the rock cannot be ascertained before extraction.
Kanarek, Julian V., "The Geology of the Adair Marble Quarry Wiarton, Ontario" (1986). Digitized Theses. 3256.