Fractures and Fracture Filling in the Guelph Formation, Steetley Quarry Flamborough, Ontario

Abstract

<p> The North Quarry (north of Ontario Highway 4) is located in Flamborough Ontario. In it, rocks of the Guelph formation are well exposed. The Guelph formation consists of dolomite and at the North Quarry has an average thickness of 30m. These rocks are cut by three predominant joint sets which have no indication of shear motion. The 030° set was formed as a result of compaction and loading; It appears to represent an upward joint propagation mirroring the Algonquin Arch trend. Joint sets 120° and 160° are a north western analogue to the conjugate pair described by Nickelson and Hough (1967) in the north eastern United States.</p> <p> Vein data and sampled minerals, using techniques such as cathodoluminescence, photoluminescence, and isotope analysis enable paragenesis of joint propagation and crystallization relationships to be inferred. Possible stress field configurations have been deduced from these data. The joint set 030° was the first to open. Next, a minor east-west trending set opened. Joint sets 120° and 160° are the last to open. The joints were infilled by cement in the order of Organics > Calcite > Sulphides > Iron Oxides. Buckle heaves in the quarry were unreliable indicators of neotectonic stress.</p>