Statistical analysis of till geochemistry in the Nelson River area, northeastern Manitoba: implications for Quaternary glacial stratigraphy

• Main Author: Wang, Ying
• Format: Master Thesis
• Language: English
• Published: University of Waterloo 2018
• Subjects: Hudson Bay; Hudson; Amery; Gillam; Long Spruce; Keewatin; Nelson River
• Online Access: http://hdl.handle.net/10012/12948

The Hudson Bay Lowland (HBL) contains a unique sedimentary record extending beyond the penultimate glaciation of the Quaternary. The complex interplay between two major ice dispersal centres (the Keewatin in the north and the Quebec-Labrador centre in the east) produced multiple till sheets in northeastern Manitoba containing Canadian Shield and carbonate rock detritus in variable proportions. In the Gillam area, the existing till stratigraphic framework consists of four tills: the Sundance Till, the Amery Till, the Long Spruce Till, and the Sky Pilot Till. This till classification is based on clast lithology, matrix color, matrix carbonate content, and clast fabric. One important aspect of this classification is that it has been established at sites where rare interstadial or interglacial organic beds separate certain tills, which facilitated their identification. The main problems are A- these organic beds seldom occur away from type sections and B- the tills show considerable overlap in their sedimentary characteristics. In addition, descriptive inconsistencies exist in the literature and different criteria have been used by various researchers over time. Altogether, these problems make it challenging to use the existing till stratigraphic framework to describe new till sections, understand the regional glacial sedimentary record, and help drift exploration. New approaches need to be tested to verify the stratigraphic framework, determine provenance of the tills and help with regional interpretations. Till matrix geochemistry contains information which can be used to discriminate till units and determine their provenance, but it has not been used widely in the HBL region in previous till studies. The aim of this thesis is to assess whether tills can be discriminated on the basis of their matrix geochemistry. To this end, multivariate statistical analysis is applied to a till geochemistry dataset. The methods used include k-means clustering and principal component analysis (PCA) to gain insights into spatial ...