Magnetic and pebble fabrics and origin of the Sunnybrook Till, Scarborough, Ontario, Canada
The early Wisconsinan Sunnybrook Till is a mud-rich, pebble-poor, dark gray to gray–brown massive diamicton that is exposed in the Scarborough Bluffs, Ontario. It is interpreted here to be till.Previous separate, magnetic, and pebble fabric studies made on the till suggest a westward ice movement ra...
| Published in: | Canadian Journal of Earth Sciences |
|---|---|
| Main Authors: | , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1987
|
| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/e87-193 http://www.nrcresearchpress.com/doi/pdf/10.1139/e87-193 |
| Summary: | The early Wisconsinan Sunnybrook Till is a mud-rich, pebble-poor, dark gray to gray–brown massive diamicton that is exposed in the Scarborough Bluffs, Ontario. It is interpreted here to be till.Previous separate, magnetic, and pebble fabric studies made on the till suggest a westward ice movement ranging from west of south to northwest. In this study, two dominant directions are found, northwest by west and northeast by north. Of these two directions, the northwest by west direction is the most common and this combined with the direction of shear in the underlying sediments and lithology of the till suggests that the glacier moved in a westerly direction.However, the fabrics are not typical of a lodgement till and to some extent resemble fabrics found in subaquatic debris-flow deposits. It is suggested that the glacier that deposited the Sunnybrook Till was buoyed up by high pore water pressure in the accumulating sediment at the sole of the glacier. Under these conditions, the till either flowed away from the zone of release at the base of the glacier and (or) was being lightly smeared by a partially grounded glacier. |
|---|