GSA Annual Meeting in Phoenix, Arizona, USA - 2019

Paper No. 237-6
Presentation Time: 9:25 AM


LIAN, Olav B., Department of Geography and the Environment, University of the Fraser Valley, 33844 King Road, Abbotsford, BC V2S 7M8, WOLFE, Stephen A., Natural Resources Canada, Geological Survey of Canada, 601 Booth St., Ottawa, ON K1A 0E8, Canada, NEUDORF, Christina M., Desert Research Institute, Division of Earth and Ecosystem Sciences, 2215 Raggio Parkway, Reno, NV 89512, HICKIN, Adrian S., British Columbia Geological Survey, PO Box 9333 Stn Prov Govt, Victoria, BC V8W 9N3, Canada and GINGERICH, Travis B., Geography, Simon Fraser University, 8888 University Dr., Burnaby, BC V5A 1S6, Canada; Department of Geography and the Environment, University of the Fraser Valley, 33844 King Road, Abbotsford, BC V2S 7M8

The timing and character of post-glacial climate-driven landscape change in western Canada is largely understood by observing changes in eolian landforms. In many cases a paucity of material suitable for radiocarbon dating has required the use of optical dating (often referred to as optically stimulated luminescence (OSL) dating) to put the nature of landscape change in a secure temporal context. In general, the two most common minerals used for optical dating are quartz and feldspar. Quartz is preferred because of its abundance in sedimentary landforms, and because its luminescence signal (‘clock’) is reset much more easily by sunlight than that for feldspar. Moreover, the appropriate luminescence signal from quartz is stable over the required time period, whereas that from feldspar fades. This so-called anomalous fading requires, where possible, additional experiments to correct or circumvent it, which adds uncertainty to calculated ages. However, the usefulness of quartz as a chronometer in recently eroded landscapes is complicated because young sedimentary quartz often has not developed the luminescence sensitivity required to make it useful for dating. This is problematic in recently-glaciated regions dominated by igneous rock, such as much of British Columbia. There is, nevertheless, hope in regions where bedrock includes sedimentary rock that has undergone little diagenesis. In this presentation we will review some of the luminescence signals observed in sedimentary quartz from British Columbia and western Alberta and discuss their utility in dating the eolian landforms in which they are found