Rice, Jessey M.;
Menzies, John;
Paulen, Roger C.;
McClenaghan, M. Beth
Microsedimentological evidence of vertical fluctuations in subglacial stress from the northwest sector of the Laurentide Ice Sheet, Northwest Territories, Canada
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Media type:
E-Article
Title:
Microsedimentological evidence of vertical fluctuations in subglacial stress from the northwest sector of the Laurentide Ice Sheet, Northwest Territories, Canada
Contributor:
Rice, Jessey M.;
Menzies, John;
Paulen, Roger C.;
McClenaghan, M. Beth
imprint:
Canadian Science Publishing, 2019
Published in:Canadian Journal of Earth Sciences
Language:
English
DOI:
10.1139/cjes-2018-0201
ISSN:
0008-4077;
1480-3313
Origination:
Footnote:
Description:
<jats:p> 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 macrosedimentological 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 and accretion and subglacial dispersion models. </jats:p>