The Uranium-Lead Geochemistry of the Mount McRae Shale Formation, Hamersley Basin, Western Australia
Date of Award
Master of Science (MS)
W. Crawford Elliott
Gerald D. Pollack
Daniel M. Deocampo
The late Archean Mount McRae Shale of the Hamersley Basin in Western Australia may record the presence of oxygen in the atmosphere before the Great Oxidation Event (2.4-2.3 Ga). Several prior studies (Anbar et al., 2007; Blum and Anbar, 2010; Duan et al., 2010; Kakegawa et al., 1998; McManus et al., 2006) have used isotopic systems to analyze the Mount McRae Shale and conclude that there was a presence of oxygen before the Great Oxidation Event. The purpose of this study is to determine if the U-Pb system can be used to see through later events to the initial conditions. The uranium-lead values of the Mt McRae Shale provide evidence of the mobilization of U and Pb gain. The geochemical disturbances have been linked to the tectonic activity (460 Ma) in the neighboring Canning basin, which could have possibly opened the geochemical system. In terms of the depositional environment the U-Pb data gathered here do not point to oxygenation of the atmosphere.
Fisher, Jennifer G., "The Uranium-Lead Geochemistry of the Mount McRae Shale Formation, Hamersley Basin, Western Australia." Thesis, Georgia State University, 2012.