Warm- vs. cool-water carbonate factories and adjacent slopes: Pennsylvanian–Early Permian Sverdrup Basin, arctic Canada
Benoit Beauchamp, Candice V. Shultz, and Kaylee D. Anderson
Department of Geoscience, University of Calgary, 2500 University Drive, NW Calgary, Alberta, Canada, T2N 1N4
ABSTRACT: Pennsylvanian–Early Permian carbonate factories of the Sverdrup Basin, Arctic Canada, and their adjoining slopes were under warm-tropical conditions in the Bashkirian–Asselian and cool-water warm-temperate conditions in the Artinskian–Kungurian. All other factors being the same, the Sverdrup Basin is a unique laboratory where these two types of slope development can be compared and contrasted. Key differences include high carbonate production, widespread boundstone margin development, shelf-margin storm protection, and early lithification for warm margins, and the lack thereof for cool margins. In addition, slope sedimentation below a shallow lysocline during the cool interval led to extensive carbonate dissolution. As a result, Artinskian–Kungurian middle and lower slopes are dominated by spiculitic chert. The Pennsylvanian–Early Permian succession consists of four third-order unconformity-bounded transgressive–regressive (T–R) sequences driven by episodic tectonics. The regressive systems tracts of each sequence recorded progradation of an accretionary margin at a time of tectonic quiescence. The warm-water accretionary margins had slopes that were either planar or exponential. Steep upper slopes formed the downward extension of a lithified boundstone margin. Strike-discontinuous erosion of that margin led to the shedding of channelized debris in the proximal middle slopes. Grainflows and proximal turbidites accumulated between areas of debris deposition. Distal turbidites forming large strike-continuous aprons were deposited in the distal part of the middle slope. This part of the slope also contains high-amplitude truncation surfaces and slump folds. The lower slope was composed of distal turbidites interstratified with hemipelagic material. The cool-water accretionary margins had sigmoidal slopes. Upper slopes formed the downward extension of a high-energy open shelf. Gravity-aided grain-dominated tempestites were deposited in the upper slope, locally associated with mud mounds. The steeper part of the sigmoidal slope was the middle slope, where key processes included slope failure and extensive sponge spicule production. Grainflow and proximal turbidites accumulated in the proximal portion of the middle slope. Mud-dominated siliceous distal turbidites associated with large-scale truncation surfaces accumulated in the distal part of the middle slope. Distal turbidites interfinger with hemipelagic siliceous shale and fine siltstone in the lower slope.
KEY WORDS: carbonate, slope, heterozoan, photozoan, Arctic
How to cite this article
Beauchamp B, Shultz CV, Anderson KD. 2013. Warm- vs. cool-water carbonate factories and adjacent slopes: Pennsylvanian–Early Permian Sverdrup Basin, arctic Canada. In Verwer K, Playton TE, Harris PM (Editors). Deposits, Architecture, and Controls of Carbonate Margin, Slope, and Basinal Settings, Special Publication 105: SEPM (Society for Sedimentary Geology), Tulsa, OK. doi: 10.2110/sepmsp.105.06.