Quaternary ice transport in the Canadian Arctic and extent of Late Wisconsinan Glaciation in the Queen Elizabeth Islands

摘要

Most of the ice-rafted debris in channels off theQueen Elizabeth Islands, Nunavut, is of local origin, particularlyin the inner part of the archipelago, but samples from the Arcticshelf contain as much as 40 percent grains from sources as faraway as 2000 km, including the Siberian shelves. Particletransport by drifting sea ice from distant shelves is an importantprocess on the Arctic continental shelf of the Queen ElizabethIslands. In the interior of the Queen Elizabeth Islands and in theViscount Melville and Lancaster sounds, particle transport islimited to distances of approximately 200 km. Mixing is morecommon among grains of coarse silt to fine sand than in the>250 #mu#m fraction, but even the latter contains debris fromsources far apart. During the Late Wisconsinan, the northern,southern, and eastern Queen Elizabeth Islands were covered byglaciers flowing radially from ice centers on the islands into theinter-island channels. Queens Channel was completely filled byice, and a glacier lobe moved north from an ice divide northwestof Devon Island to Peary Channel. This lobe redistributedcrystalline and carbonate erratics that are derived in part from astrongly weathered and degraded till that was deposited by apre-Late Wisconsinan glaciation, and in part from glacialerratics that were deposited below the marine limit by icebergsduring the Late Wisconsin deglaciation. Tills from easternBathurst Island are locally derived and devoid of erratics, butsubmarine tills west of Bathurst Island contain crystallineerratics that could be from either the Canadian Shield or Victoria Island.