Quaternary stratigraphy and geologic history of the Charlie Lake (NTS 94A) map-area, British Columbia

Two Cordilleran and three Laurentide glacial advances are recorded by Quaternary sediments in the Charlie Lake map-area (NTS 94A). The advances are inferred from the presence of exotic clasts derived from the Canadian Shield, fluvial deposits, glaciolacustrine deposits, and tills within nested paleo-valleys excavated during three interglaciations. The Late Wisconsinan Laurentide glaciation was the most extensive Laurentide glaciation, and the only one recognized in western Alberta south of the study area. Coalescence of Late Wisconsinan Laurentide and Cordilleran Ice Sheets is not recognized within the study area. Advancing Late Wisconsinan Laurentide ice blocked the east-flowing drainage and impounded Glacial Lake Mathews within paleo-Peace River valley and its tributaries. More than 100 m of fine sediment, deposited by suspension settling and density underflows were deposited in the centre of the basin. Weak, plastic clay layers within the glaciolacustrine sequence have developed shear planes on which more than 900 landslides have occurred.