Project Description

Quaternary Glaciomarine Environments west of Committee Bay, central mainland Nunavut (2000-2002)

Martine Giangioppi¹, Edward C. Little*, Travis Ferbey², Carl Ozyer³ & Daniel J. Utting⁴ Canada-Nunavut Geoscience Office, Iqaluit

¹Départment d'histoire et de géographie, Université de Moncton, 165 Massey, Moncton, NB, E1A 3E9.

²School of Earth and Ocean Sciences, University of Victoria, P.O. Box 3055, Victoria B.C., V8W 3P6.

³Department of Earth Sciences, University of Western Ontario, London, ON, N6A 5B7.

⁴Department of Earth Sciences, Simon Fraser University, 8888 University Drive, Burnaby, B.C., V5A 1S6.

Correspondence: elittle@NRCan.gc.ca

Abstract

Maximum marine transgression limits are identified along the eastern and northern peripheries of the Ellice Hills map sheet area (NTS 56P), west-central coast of Committee Bay, Nunavut. An age estimate of 9000 calander (cal.) yrs BP to 8600 cal. yrs BP is tentatively assigned to the absolute maximum marine limit (ca 240-255 m asl) along this coastline, based on marine features at comparable elevations along the northeast coast of Committee Bay. The lowest marine limit, observed 50 km inland at ca 180 m asl, is associated with a later marine highstand. The westward decreasing trend exhibited by the maximum marine limits is the result relative sea-level fall during southwestward retreat of Keewatin ice. Marine fossils commonly form a shell lag atop offshore marine muds or, rarely, are in situ. Relative sea-level fall and progressive ice retreat resulted in a succession of marine communities following the initial colonization by ice-proximal species such as Portlandia arctica.

Ice-flow indicator mapping in the Committee Bay supracrustal belt provides new evidence for a complicated ice-movement chronology during the Late Wisconsinan (NTS 56K, J/8-16, O/1-8 and P). Three main phases of ice movement have been identified at the regional scale. The oldest is northerly and is ubiquitous throughout most of the area. This was followed early in the deglaciation sequence by northeastward flow in the eastern part of the area and northwesterly flow in the west. Finally, there is a north-northwesterly flow south of the Chantrey moraines, associated with ice flow from the Keewatin Ice Divide. Results from drift prospecting studies indicate that till geochemistry reflects a clear northerly direction of glacial transport. Most of the known gold showings are recognized in the gold grain counts and/or the gold values in the till matrix, but at least two previously unknown potentially Au-rich domains have been identified.

Natural Resources Canada, Committee Bay Quaternary Project.