Microsedimentological evidence of vertical fluctuations in subglacial stress from the northwest sector of the Laurentide Ice Sheet, Northwest Territories, Canada.

• Main Authors: Rice, Jessey, Menzies, John, Paulen, Roger C., McClenaghan , M. Beth
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: NRC Research Press (a division of Canadian Science Publishing) 2018
• Subjects: Canada; Northwest Territories; Pine Point; Ice Sheet
• Online Access: http://hdl.handle.net/1807/94104; http://www.nrcresearchpress.com/doi/abs/10.1139/cjes-2018-0201

The past-producing Pine Point lead-zinc mining district, Northwest Territories, Canada, provides a unique opportunity to study the role of glacial dynamics in a thick, continuous till succession that has not been influenced by the underlying bedrock topography. Parts of the Pine Point mining district are covered by >20 m of subglacial Quaternary sediments (till) associated with the former Laurentide Ice Sheet. Till facies exposed in unreclaimed open-pit K-62 have been classified into four separate units. Micro- and macro-sedimentological analyses were undertaken to identify the change in subglacial stress during sediment deposition and across till unit boundaries. An analysis of high- and low-angle microshears (lineations) in thin sections produced from these till units indicate that there is a noticeable decrease in the abundance of low-angle shear features immediately below till unit boundaries. The deformation of low-angle shears in the underlying tills was likely caused by remobilization of the overlying till unit. This remobilization is consistent with aggradation-constant entrainment decay mechanisms for subglacial till emplacement/accretion and subglacial dispersion models. The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author.