Depositional, Diagenetic and Structural History of the Devonian Succession beneath the Athabasca Oil Sands of Northern Alberta
Date
2018-08-15
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Abstract
Three lengths of core with a cumulative total of 1038 m from the Devonian succession beneath the Athabasca oil sands in northeastern Alberta were studied in detail to better understand the depositional, diagenetic and structural history of these rocks, and ultimately to provide insights into the origin and timing of karsting in the region. The succession in the study area encompasses ten formations as well as the Precambrian crystalline basement. Facies analysis based on megascopic and microscopic observations was performed to interpret the depositional environment of each formation. Depositional environments of variable settings and bathymetry range from fluvial sandstone to basinal carbonate. Diagenetic features were also recorded for each unit, from the time of deposition to present day. Thirty-one diagenetic features were identified, their origins interpreted and integrated in elaborate paragenetic sequences for the entire succession. Additional geochemical analysis helped reinforce initial interpretations based on thin section petrography. Dissolution and thermochemical sulfate reduction of thick evaporite deposits are interpreted to have caused both karsting in the overlying sediments and extensive recrystallization of the underlying carbonates. A fault in the region, likely rooted in the crystalline basement, may have enhanced certain diagenetic processes as well as the removal of evaporites.
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Devonian
Citation
Garroni, N. D. (2018). Depositional, Diagenetic and Structural History of the Devonian Succession beneath the Athabasca Oil Sands of Northern Alberta (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/32818