Ribbed moraines and subglacial geomorphological signatures of interior-sector palaeo-ice sheet dynamics

Transverse, subglacial bedforms (ribbed moraines) occur frequently in southern Keewatin, Nunavut, Canada, where they record a complex glacial history, including shifting centers of ice dispersal and fluctuating basal thermal regimes. Comprehensive mapping and quantitative morphometric analysis of the subglacial bedform archive in this sector reveals that ribbed moraines are spatially clustered by size and assume a broad range of visually distinct forms. Results suggest that end-member morphologies are consistent with a dichotomous polygenetic origin, and that a continuum of forms emerged through subsequent reshaping processes of variable intensity and duration. Translocation of mobile, immobile and quasi-mobile beds throughout the last glacial cycle conditioned the development of a subglacial deforming bed mosaic, and is likely responsible for the patchy zonation of palimpsest and inherited landscape signatures within this former core region of the Laurentide Ice Sheet. Comparison against field evidence collected from central Norway suggests that bedforming processes can be locally mediated by pre-existing topography.

Handwritten sheet of paper detailing the cost of transporting boxes containing the Gravatt’s level

Handwritten sheet of paper detailing the cost of transporting boxes containing the Gravatt’s level from London to St. Catharines, April 1847.

Handwritten sheet of paper detailing the cost of transporting boxes containing the Gravatt’s level

Handwritten sheet of paper detailing the cost of transporting boxes containing the Gravatt’s level from London to St. Catharines. This sheet is signed by S.D. Woodruff, Jan. 11, 1847.

Pay roll voucher from the Engineer Department of Port Dalhousie and Thorold Railway Extension for repairs to fences and cattle guards etc. in the months of April and May. This document is attached to a time sheet, May 11, 1857

Pay roll voucher from the Engineer Department of Port Dalhousie and Thorold Railway Extension for repairs to fences and cattle guards etc. in the months of April and May. This document is attached to a time sheet, May 11, 1857.

Annual meeting of the Long Point Company attached to a copy of the May 31, 1882 balance sheet

Annual meeting of the Long Point Company (1 page, printed) attached to a copy of the May 31, 1882 balance sheet (1 page, printed). The meeting has the name J.I. Mackenzie, assistant secretary-treasurer on the bottom and the balance sheet has the names J.I. Mackenzie, secretary treasurer and Geo. H. Gillespie, auditor on the bottom of the page, June 6, 1882.

Balance sheet for 14 months ending May 31, 1879

Balance sheet (1 page, printed) for 14 months ending May 31, 1879.

Balance sheet including copy of the cash book and auditor’s report for 12 months ending May 31, 1880

Balance sheet including copy of the cash book and auditor’s report (1 page, printed) for 12 months ending May 31, 1880.

Balance sheet including copy of the cash book and auditor’s report for 12 months ending May 31, 1881

Balance sheet including copy of the cash book and auditor’s report (1 page, printed) for 12 months ending May 31, 1881.

Rough copy of the balance sheet to May 31, 1882

Rough copy of the balance sheet (3 pages, handwritten) to May 31, 1882.

Balance sheet including copy of the cash book and auditor’s report for 12 months ending May 31, 1882

Balance sheet including copy of the cash book and auditor’s report (1 page, printed) for 12 months ending May 31, 1882.

Receipt from W. H. Eckhardt, Pianos, Organs, Sheet Music and Musical Merchandise for piano

Receipt from W. H. Eckhardt, Pianos, Organs, Sheet Music and Musical Merchandise for piano, May 9, 1887.