Slave Geological Province: An Archetype of Glaciated Shield Terrain

Abstract

The Slave Geological Province of the Tundra Shield is a Late Archean craton extending from the north shore of Great Slave Lake in the Northwest Territories to the Coronation Gulf in Nunavut. Underlain by metavolcanic and metasedimentary rocks intruded by granitoid plutons, the region is rich in gold, base metals, and diamonds and hosts numerous historic, active, and prospective mines. Most recently glaciated in the Late Wisconsinan, till and glacifluvial sediments form the most prevalent surficial materials. Glacial landscape features reflect complex ice flow patterns recording several different events. Raised post-glacial marine sediments are significant in the north along the Coronation Gulf at elevations below 200 masl, whereas glacilacustrine sediments related to glacial Lake McConnell are abundant in the south. Ground ice in glacigenic sediments has been preserved since deglaciation as much of the region also lies well within the zone of continuous permafrost. Segregated ice occurs separately within glacimarine and glacilacustrine sediments, and polygonal terrain is abundant on outwash sediments. Glacially derived ground ice includes buried glacial ice within glacifluvial outwash deposits and buried glacial and meltwater ice within eskers. Sediment-rich ice has also been encountered within hummocky till terrain during mine development operations. Surficial features attributed to partial thawing, and creep of massive ground ice, are regionally apparent. Although massive ice has been encountered in only a few locations to date, ground ice may be common within this glaciated region of the Tundra Shield.