An Examination of the Geomorphology and Sediment Texture of the Exeter Lake Esker

Presenter:

 

Grayson Bilak – grayson.bilak@carleton.ca

 

Authors:

 
G. Bilak – Carleton University, Ottawa, ON, Canada
D.I. Cummings – DCGeo Consulting, Aylmer, QC; Carleton University, Ottawa, ON, Canada
 

Summary:

 

The Exeter Lake Esker (ELE) extends across the Northwest Territories from Dubawnt Lake to Exmouth Lake and, sampling led to the discovery of the Lac de Gras kimberlite field. dataset incorporates the ArcticDEM, aerial photos, esker and till samples, low-level fly-over footage, and sediment texture photos. As a build up to the interpretation of the integrated dataset, the ArcticDEM and selected field photos are analyzed here.

Variations in morphology are observed across the ELE, with repeated transitions between confined ridges and wider, less confined bodies. Ridge elements are on average 212 m wide and 1007 m long. They exhibit a variety of shapes, including sharp-crested, multi-crested, flat-topped, and irregular morphologies. The wider sediment bodies are on average 777 m wide and 1891 m long. They present as either fans at breaks in the esker or as ridge-cored complexes. The esker is highly segmented. Breaks make up 31% of the total length of the esker and consist of lakes, zones of exposed bedrock or thin till cover, and areas which resemble braided-fluvial channels. These observations indicate the ELE is more complex than traditional chevron mapping symbols and further examination of the ELE geomorphology may provide greater insight into Laurentide deglaciation.

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