Geomorphology and sedimentology of the Holocene Slave River delta, Northwest Territories

• Main Author: Vanderburgh, Sandy
• Other Authors: Smith, Derald G.
• Format: Master Thesis
• Language: English
• Published: University of Calgary 1987
• Subjects: GB 428.5 C2 V36 1987a; Geomorphology - Slave River (Alta. and N.W.T.); Sedimentation and deposition - Slave River (Alta. and N.W.T.); Deltas - Northwest Territories; Geology - Slave River (Alta. and N.W.T.); Geology; Stratigraphic - Holocene; Alta; Northwest Territories; Great Slave Lake; Barrier Islands; Fort Smith; Buffalo River; Little Buffalo; Little Buffalo River; Tethul River; Slave River
• Online Access: http://hdl.handle.net/1880/23891; https://doi.org/10.11575/PRISM/20454

Bibliography: p. 65-68. The Slave River Delta (8,300 km2) is a long (170 km), narrow ( 42 km) alluvial plain which extends north from the Slave River Rapids at Fort Smith to the Great Slave Lake. The delta plain is flanked by the Talston River, Tethul River and Canadian Shield to the east and Little Buffalo River to the west. Analysis of 36 litho-stratigraphic logs from river cutbanks indicate a sandy wave-influenced delta inferred from the dominance of wave-associated sedimentary structures in the middle, upper shoreface and beach deposits. The cutbank exposures terminate approximately 235 km downriver from Fort Smith where mud dominates much of the surficial sediment. Receiving basin morphology, water depth and termination of rebound in the region appears to be accountable for the transition. Radiocarbon analysis of 11 wood samples from river cutbanks and a paleoshoreline reconstruction indicate that the delta prograded at an average rate of 20.76 metres per year from 8,070 to the present. A tilt rate of 21.2 cm/km due to isostatic rebound, normal to the retreating ice margin, has been calculated for the Slave Delta region. The subaqueous delta front exhibits several unique morphologic features including barrier islands, offshore bars, tensional cracks, subaqueous slumps and pressure ridges at 59 m lake depth. The barriers and off shore bars consist of medium sand while the slumps and pressure ridges are interpreted to be of mud.