Facies and stratigraphical analyses of glacial and interglacial sediments at Morgan Bluffs, Banks Island, Canadian Arctic Archipelago

Abstract

Stratigraphical exposures of both glacial and non-glacial sediments at Morgan Bluffs, a >6-km long exposure on the east coast of Banks Island, comprise a discontinuous archive of Quaternary environmental change. A detailed facies analysis of the sediments and a new stratigraphical framework is incompatible with the many climatostratigraphical units proposed previously. Instead, three distinct intervals of sedimentation are recognized. The first records the progradation of a delta, followed by fluvial aggradation of a braided river valley perhaps ∼1 Ma. The second documents glacigenic sedimentation, including fluctuations of a tidewater glacier margin, in a marine basin more than 0.78 Ma. The third records till deposition by the NW Laurentide Ice Sheet during the Late Wisconsinan, followed by the progradation of a deglacial, ice-contact delta into an ice-dammed lake ∼12.8 cal. ka BP. The revised stratigraphical framework adds important new terrestrial observations to a sparse and fragmentary data set of Quaternary environmental change in the Canadian Arctic. This study challenges former references and correlations to the previously proposed climatostratigraphical framework and nomenclature.