Late Wisconsin ice movements and deglaciation: in the N.E. Porcupine Hills area, Alberta

• Main Author: Love, Michael Andrew
• Format: Article in Journal/Newspaper
• Language: English
• Published: University of Calgary 1977
• Subjects: GB 588.15 L67 1977 Microfiche; Glacial landforms - Alberta - Porcupine Hills; Geomorphology - Alberta - Porcupine Hills; Boydell; Marguerite; Ice Sheet
• Online Access: https://dx.doi.org/10.11575/prism/23589; https://prism.ucalgary.ca/handle/1880/15023

Bibliography: p. 101-112. : The study of a 1476 km2 area located in the N.E. Porcupine Hills of Southwest Alberta, has provided most evidence for the movement and retreat of two Late Wisconsinan ice masses; the hybrid Marguerite (western) and Lochend (eastern) ice sheets. Although most evidence is given for the last glaciation, information is cited which relates to the earlier eastern Labuma and Maunsell advances of glacial Events Three and Two age respectively. No deposits from earlier western incursions of ice have been found, though it is known from mapping in an adjacent area to the west (Waters, 1975) that such advances entered that area. _x000D_ Evidence relating to the Labuma advance consists of the high level igneolis and metamorphic erratics. Maunsell deposits are much more coherent and may be found in a small zone in the southwest portion of the area. Hybrid Marguerite till displays mixed characteristics, though on the basis of pebble lithology it can easily be differentiated from the eastern tills in the area. The hybrid Marguerite glacier undoubtedly assimilated foreign eastern material as it flowed southwards over areas previously traversed by Laurentide advances. It was deflected southwards by the Lochend ice sheet which lay to the east of the mountains. Laboratory analyses confirm the eastern origin of the Lochend till. Both ice masses are considered to have been coeval. _x000D_ During deglaciation, which was effected by both ice stagnation and orderly re treat, a large proglacial lake (Lake Eden) was impounded in the area for which two still-stands have been recognized. An efficient system of meltwater channels formed at this time as the lake was drained. From 14c dates given by various researchers (e.g. Harris and Boydell, 1972) the area most probably became free of ice during the very early Holocene.