The Drift des Demoiselles on the Magdalen Islands (Quebec, Canada): sedimentological and micromorphological evidence of a Late Wisconsinan glacial diamict

作者：Remillard Audrey M^*; Hetu Bernard; Bernatchez Pascal; Bertran Pascal

来源：Canadian Journal of Earth Sciences, 2013, 50(5): 545-563.

DOI：10.1139/cjes-2011-0115

The deposits identified as being the Drift des Demoiselles, which is the upper unit of the southern Magdalen Islands (Quebec, Canada), belong to two units of different origin, glacial and glaciomarine. At Anse a la Cabane, the glacial deposit comprises two subunits: a glacitectonite at the base and a subglacial traction till at the top. Numerous glaciotectonic deformation structures suggest ice flow towards the southeast. The till is above an organic horizon dated to similar to 47-50 ka BP. New data presented here show that the southern part of the Magdalen archipelago was glaciated during the Late Wisconsinan. We relate this ice flow to the Escuminac ice cap, whose centre of dispersion was located in the Gulf of St. Lawrence, northwest of the islands. At Anse au Platre, the top of the Drift des Demoiselles is a glaciomarine deposit. At Anse a la Cabane, the till is covered by a stratified subtidal unit located at similar to 20m above sea level. Both were deposited during the marine transgression that followed deglaciation. At Anse a la Cabane, three ice-wedge casts truncate the till and the subtidal unit, providing evidence that periglacial conditions occurred on the archipelago after deglaciation.

• 出版日期2013-5