Late Quaternary Glacial and Environmental History of the Burstall Pass Area, Kananaskis Country, Alberta, Canada
Brandon D. Beierle, Derald G. Smith, Leonard V. Hills
We used integrated multiproxy analysis of a lake sediment core and glacial geomorphology to reconstruct the late Pleistocene and Holocene climate and geomorphic evolution of the Burstall Pass area, Kananaskis Country, Alberta, Canada. Analysis of macrofossils, pollen, sedimentology, and sediment geochemistry from a lake sediment core and geomorphology and tephrochronology of glacial moraines provide evidence for multiple modes of climate during the last ca. 11,000 yr. An advance of the Robertson Glacier prior to ca. 9200 14C BP is correlated to the Crowfoot advance and was the largest of the postglacial period. Immediately following this event, increased lake productivity and the deposition of marl as well as increased arboreal/nonarboreal pollen (AP/NAP) ratios suggest that the climate warmed, possibly accompanied by increased aridity. Decreased turbidity and clastic sediment flux in Lower Burstall Lake during the early Holocene suggest reduced glacial runoff and may indicate the complete ablation of the Robertson Glacier shortly after 10,000 14C BP. Clastic sediment flux to Lower Burstall Lake remained minimal until after ca. 3500 14C BP, when decreasing LOI (loss-on-ignition) organic carbon levels in lake sediments signaled the return of glacial runoff to the lake system. The largest Neoglacial advance in the Burstall Pass area appears to have been the most recent and was followed by rapid recession during the 20th century.