O.B.Lian, D.J.Huntley and S.A.Wolfe.

Optical dating of eolian dune sand from the Canadian prairies. Géographie Physique et Quaternaire 56, 191-202, 2002. Accepted June 19, 2003 and published May 2004.

Optical dating is a well-established method that is used to determine the

time elapsed since quartz or feldspar grains were last exposed to sunlight,

which usually dates the time elapsed since their burial in a sedimentary

deposit. Only a few seconds of direct sunlight are needed to reset the

"mineral clock", making the method ideal for dating the formation of eolian

landforms. In this paper we describe how we use violet luminescence that is

emitted in response to near-infrared excitation of sand-sized K-feldspar

grains to date the time of formation of eolian dunes on the Canadian prairies.

Using the multiple-aliquot with thermal transfer correction method, together

with a test for sufficient sunlight exposure, and a correction for anomalous

fading, we are able to produce accurate optical ages ranging from 150 years

to more than 11 ka with precision usually better than 10% at 2. Ages are

given for dunes in the Dundurn and Elbow sand Hills of south-central

Saskatchewan, the climatic significance of which is provided in a paper

also in the present volume. Knowledge of when the dunes were

stable, and when they were not, is used to help understand the nature and

timing of Holocene climate change in the area.