CGRG Bibliography of Canadian Geomorphology
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Author : Demchuk, T.E.; and Levson, V.M.
Date : 2007.
Title : Geomorphology of a glaciofluvial delta using aerial photograph and LiDAR mapping, ground penetrating radar, and capacitively coupled resistivity surveys, Northeast British Columbia, Canada.
Publication : CANQUA Ottawa 2007. Canadian Quaternary Association Conference, June 4-8, 2007. Carleton University, Ottawa, Ontario, Canada.
Issue :
Page(s) :
Abstract
The plains region of northeast British Columbia is characterized by low relief, and subtle glacial landforms commonly masked by forest cover. The dominant surficial materials in the region are morainal and organic, while glaciofluvial (or fluvial) sands and gravels are rare. Aggregate resources are in high demand by the oil and gas industry for infrastructure development, and to date numerous methods for locating such resources have been employed with variable success. Most recently, a combination of feature identification from LiDAR imagery and shallow ground geophysics have been successfully employed to find aggregate deposits and interpret the genesis of glaciofluvial features. This study investigates a large glaciofluvial feature, interpreted as a glaciofluvial delta, deposited during retreat of the Laurentide Ice Sheet. Recently it has been studied in detail using aerial photograph and LiDAR-image mapping, test pitting, drilling, ground penetrating radar (GPR), and capacitively coupled resistivity (CCR) surveys. The feature covers an area of approximately seven square-kilometres, including interlobe and Holocene channel-cut areas, and is composed of six lobes. The sedimentology of individual lobes is variable. Material occurring in them can range from pebbly fine to coarse sands to cobble-sized gravel with occasional pebble-sized diamicton intraclasts and rare, 3 cm thick, silt interbeds. The delta is the only accessible aggregate source for the area, making it a valuable resource, and the compositional variability of this feature presents a challenge to those mining the feature for its aggregate resources. Capacitively coupled resistivity surveys can be used to investigate the configuration and morphology of resistive (or conductive) bodies and also predict sediment texture based on resistivity values. To this end a combination of GPR and CCR surveys have been used to establish a model of the subsurface architecture including an approximation of sediment type. These investigations, together with test pitting and mapping, have helped establish a history for the formation of this feature and been used to refine the aggregate potential of the area by constraining the location of sand versus gravel bodies within it.
Bibliography of Canadian Geomorphology