Estimates of the Age of the Existing Relief within the Southern Rocky Mountains of Canada

Abstract

U-series ages and palaeomagnetic data for Minima are >0.04 to 0.07 m 1000 yr-1. calcite speleothems collected from seven relict These results are extended to estimate ages for phreatic caves preserved in valley walls in the the mean relief of 1340 m that exists between Crowsnest Pass and Columbia Icefield areas valley floors and adjacent crestlines in these of the Canadian Rocky Mountains are used to mountains. The age estimates range 0.65 to derive local mean maximum, or mean maxi- 33.5 Ma; it is argued that the true age is most mum and minimum, rates of valley deepening likely to fall between 1.2 and 12 Ma, and 6 to for the timespan 180 to >350 Ka BP. Maxi- 12 Ma is the preferred time range suggested mum rates range 0.13 to 2.07 m 1000 yr-1. by the results.