CGRG Bibliography of Canadian Geomorphology
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Author : Beaudoin, A.
Date : 2010.
Title : A postglacial macrofossil record from the Grande Prairie area, Alberta.
Publication : Prairie Summit - Le sommet des Prairies. Joint Conference of Canadian Association of Geographers, Canadian Cartographic Association, Canadian Geomorphology Research Group, Canadian Remote Sensing Society / Conférence conjointe de l’Association canadienne des géographes, l’Association canadienne de cartographie, le Groupe canadien de recherche en géomorphologie, la Société canadienne de télédétection. June 1 to 5, 2010. Regina, Saskatchewan.
Issue : Program and Abstract Volume.
Page(s) : 78.
Abstract
The Wood Bog (informal name) site is located east of Grande Prairie in the Boreal Mixedwood Ecoregion of northwest Alberta. Fifty samples from a 3 m sediment section, exposed in the walls of a dugout, have been processed to extract macrofossils. The record’s base dates to about 9600 radiocarbon years ago; it provides a continuous sequence through the Holocene. A taxonomically rich and varied assemblage has been recovered and includes plant fragments, insect parts, mollusc shells, seeds (s.l.), Charophyte oogonia, and ostracodes. Blue-grey clay exposed at the base likely represents Glacial Lake Peace. Above this is a 65 cm thick wood-rich layer. Much of this wood exhibits clear signs of beaver-gnawing. This is overlain by organic-rich mud, then a layer containing abundant mollusc shells. Samples from this lower sequence are dominated by seeds from aquatic and emergent plants, including Potamogeton spp., Zannichellia palustris, Utricularia, and Ranunculus sceleratus, and aquatic molluscs, such as Gyraulus spp., Promenetus, and Pisidium. The upper sequence (about 2 m) consists of peat, and shows a marked transition between seed assemblages dominated by Typha latifolia to ones dominated by Carex spp., with spruce (Picea) needles appearing towards the top. Climate signals throughout the record are weak. The lower part is a terrestrialization sequence, recording a beaver dam and an in-filling beaver pond, and indicating that lowland terrain was rapidly re-occupied by plants and animals following drainage of Glacial Lake Peace. The record also provides evidence for the geomorphic activity of beavers during the early Holocene.
Bibliography of Canadian Geomorphology