The Sequential development of a rock glacier-like landform, Mount Assiniboine Provincial Park, British Columbia
LccGB 588 A8 Y35 1979 Microfiche
LcshRock glaciers - Mount Assiniboine Provincial Park
Frozen ground - Research
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AbstractThe identification and use of rock glaciers and related deposits as paleoclimatic indicators have been problematic to date because of an over-dependence on surface morphology as the basis for discrimination among forms. Accordingly, the objectives of this research are threefold: firstly, to distinguish between rock glaciers and similar alpine deposits by their sedimentological properties; secondly, to demonstrate the sequential development of a rock glacier-like feature through the Holocene; and, finally, to synthesize the above objectives in order to develop a model for the complex genesis of one such feature over time. Mount Assiniboine Provincial Park was chosen for study on the basis of the presence of a range of contrasting glacial and peri g lacial landforms within a relatively small area. Of these landforms, a rock glacierlike feature was investigated because pre-field and early field investigation suggested the possible complex manner in which it had evolved. Methods for the analysis of the surface morphology, relative degree of plant cover, sorting, and chemical and mechanical weathering were employed to establish the relative ages of the different areas of the landforrn. Mechanical, statistical and graphical techniques were used to analyze the nature and distribution of the sediments and, therefore, to infer the processes involved in the formation of the feature. The surface sediments of a talus slope, a complex ablation feature with certain rock glacier characteristi c s and an ice-cored mora ine were also sampled to provide basic sedimentological information for contrast with the rock glacier-like landform during the multiple discriminant analysis. The following are the primary conclusions of the study: four periods of Holocene glacial/periglacial activity apparently led to the present configuration of the rock glacier-like feature. The events appear to correspond with the three Neoglacial advances recognized in the Rocky Mountains of the United States (e.g., the Gannet Peak, the Audubon and the Triple Lakes) and the early Holocene Chateau Lake Louise Event of the Canadian Rockies. The two oldest zones of the feature seem to have been affected by rock glacier transport and deposition, whereas the younger areas were probably the scene of glacial erosion and deposition. It appears that rock glacier transport affects the nature and distribution of sediments differently than does the ablation of debris on ice-cored moraines, the former display ing crude sorting and orientation, while the latter apparently has more random distribution and orientation patterns.
Bibliography: p. 135-141.