HG 268.40-268.55 Thin Section

This is a coarse grained sample with some very fine grained domains throughout the sample. The clast shape and size range from small to large, as well as angular to sub-rounded. Grain crushing is the most prevalent in this sample. It also contains some rotation structures and minor necking structures. Lineations and grain stacking can also be seen.

HG 384.60-384.70

Dark brown sediment with scattered amounts of small clasts and medium clasts as well. Clast shape ranges from sub-angular to sub-rounded. Lineations and water escape structures are abundant in this sample.

HG 37.15-37.25

Brown sediment with clasts ranging from small to large in size. Clast shape ranges from sub-angular to rounded. Rotation structures were abundant throughout the sample, along with necking structures. Lineations and edge-to-edge grain crushing were also present in minor amounts.

J-2C-A

Brown sediment with clasts ranging from small to large in size. The clast shape ranges from angular to sub-rounded. Water escape structures can be seen in this sample among the more clay rich areas. Lineations and a few rotation structures can also be seen in this sample. There were minor amounts of grain stacking/crushing present.

Determining rotational direction of rotation structures using prolate shaped grains within till

Micromorphology is used to analyze a wide range of sediments. Many microstructures have, as yet, not been analyzed. Rotation structures are the least understood of microstructures: their origin and development forms the basis of this thesis. Direction of rotational movement helps understand formative deformational and depositional processes. Twenty-eight rotation structures were analyzed through two methods of data extraction: (a) angle of grain rotation measured from Nikon NIS software, and (b) visual analyses of grain orientation, neighbouring grainstacks, lineations, and obstructions. Data indicates antithetic rotation is promoted by lubrication, accounting for 79% of counter-clockwise rotation structures while 21 % had clockwise rotation. Rotation structures are formed due to velocity gradients in sediment. Subglacial sediments are sheared due to overlying ice mass stresses. The grains in the sediment are differentially deformed. Research suggests rotation structures are formed under ductile conditions under low shear, low water content, and grain numbers inducing grain-to-grain interaction.

HG 114.40-114.50

Brown sediment with clasts ranging from small to medium in size. Clast shape ranges from angular to sub-rounded. Lineations are the most abundant microstructure, but this sample also includes some comet and rotation structures as well.

WB-6a

Brown sediment with clasts ranging from small to large in size. Clast shape ranges from angular to sub-rounded. Necking structures are abundant within this sample, mainly between larger aggregates. Some rotation structures and lineations can also be seen. Comet structure and grain stacking can be seen in minor amounts.