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Author : Campbell, J.E.
Date : 2001.
Title : Phelps Lake Project: Highlights of the Quaternary Investigations in the Bonokoski Lake Area (NTS 64M-11, -12, -13, and -14).
Publication : Summary of Investigations 2001, Volume 2, Saskatchewan Geological Survey, Saskatchewan Energy Mines, Miscellaneous Report
Issue : 2001-4.2.
Page(s) :
Abstract
Quaternary geological investigations were initiated in the Bonokoski Lake area (64M/11, /12, /13, and /14) as part of the multidisciplinary, multi-year Phelps Lake Project. The Quaternary component of the project involves surficial geological mapping at the 1:100,000 scale, studying the glacial history, and conducting regional till sampling surveys. Drift cover is extensive in this region. Till, boulder fields and organic terrain the dominant surface materials. Sand and gravel deposits are also prevalent, and are primarily associated with the large esker-kame complexes. No evidence of glacial lake sediments was encountered in the map area. Enormous erratics were encountered in a number of locations. The dominant glacial landforms are ground moraine, hummocky ground moraine, stagnant-ice moraine, recessional moraines, ridged moraine, and minor Rogen moraine. Six large esker systems cross the map area, several of which are located within subglacial channels. The largest system is a tunnel valley that begins in the NWT and is occupied by Mackenzie Creek, and the Gebhard, Bonokoski and Pikwuche lakes. Boulder or block fields are prominent features in the Bonokoski Lake area. Boulder lags derived from till, slightly transported boulders and felsenmeer all create level concentrations of boulders on the surface. The felsenmeer and the short-travelled boulder fields are characterised by predominantly monolithologic, angular boulders that are similar in size. Change in the rock type of the boulders generally corresponds to change in the underlying or nearby bedrock. The greatest abundance of these block fields occurs in granitic terrain. Although the multiple glaciations have advanced and retreated over northern Saskatchewan, the dramatic landscape of Bonokoski Lake area is primarily a product of deglaciation during the retreat of the late Wisconsin an ice sheet. Recessional moraines, stagnant -ice moraine and well-developed esker systems are evidence of a slow retreating to stagnant ice margin. Deglaciation of the area appears to have been dominated by periods of stagnation and downwasting interspersed with seasonal pulses of the ice margin. Downwasting would have produced abundant meltwater, which drained subglacially towards the ice margin as high volume, turbulent sheet floods, and through subglacial channels and tunnel valleys.
Bibliography of Canadian Geomorphology