Dating the Asulkan s East Spill Over Zone. Cali Bingham, Kara Piman, Blair Underhill, Martin Demidow, Sam Ward, Derek Heathfield and Ahmed Mumeni

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1 Dating the Asulkan s East Spill Over Zone Cali Bingham, Kara Piman, Blair Underhill, Martin Demidow, Sam Ward, Derek Heathfield and Ahmed Mumeni

2 Purpose and Objectives Establish approximate dates of terminal and recessional moraines of the Asulkan Glacier, using: Lichenometry Dendrochronology Air Photo Interpretation Determine dates of avalanche occurrence and subalpine fir germination episodes on the upper two terminal moraines, using: Dendrogeomorphology Dendroclimatology

3 Site Description Approximately 75km from Golden, British Columbia, within the Columbia Mountain range in Glacier National Park. Accessible via the Asulkan Valley Trail.

4 The 2 Groups Blair, Derek, Sam, Ahmed, and Martin conducted their research on the lowest two moraines as well as the top most recent moraine. Cali and Kara conducted their research on the top two most recent moraines.

5 Lichenometry Relatively new technique for dating wood, soil and rock. Technique in Canada developed by the late Roland Beschel We We will attempt to date the Asulkan Glacier and its recession using lichenometry on 4 separate moraines

6 Lichenometry Methodology Field measurements Take measurement of lichen thalli in x and y directions with digital caliper Only yellow-green Rh. Geographicum were sampled Only chose largest lichens at each moraine Thalli had to be ellipsoidal or circular Measurements were not taken where one thalli had overtaken another one Did not measure lichen on top of rock 30 thalli samples taken at each moraine Sampling attempted to span entire moraine

7 Results - The Boys Based Based on McCarthy s s growth curve, our 3 moraines dated as follows: Terminal: 270 years (1738) Lower recessional: 153 years (1855) Upper recessional: 102 years (1906)

8 Lichen Growth Curve

9 Lichenometry Methods Upper 2 Moraines Lichen diameters were measured on the entire ridge of the lower moraine and the terminal portion of the upper moraine. Samples were divided into lower, mid and upper sections. The mean lichen diameter was calculated for each of these sections.

10 Results The Girls Ecesis: Ecesis: 35 years (McCarthy, 2003) Lower: Lower: 180 years (1828) Mid: Mid: 140 years (1868) Upper: Upper: 90 years (1918)

11 Lichen growth curve Lower moraine at 180 years old Upper moraine at 90 years old

12 Potential error Underestimates could be due to: Using mean values rather than max thalli size Non-uniform snow cover Overestimates due to: Lichen adjacent to streams Using Using a pre-existing existing growth curve developed for the Illecillewaet Glacier

13 Dendrochronology Dendrochronology has proved to be an invaluable tool for dating events & for providing robust annually resolved paleoenvironmental insights Daniel J(uniper?) Smith, Dendroglaciology Dendrogeomorphology Dendroclimatology

14 Dendroglaciology Reconstructing past glacial activities & maximum glacial extent (Smith & Lewis, 2007)

15 Dendroglaciology The Boys Methods: Initially slight downward angle core root crown interface & minimize age errors Rotten pith cores = corer handle height & standard breast height Tree whorl count for smaller trees Analysis conducted at UVTRL Closest and most relevant data to study area used to extrapolate ecesis intervals: 45 years for sub alpine fir 41 years for mountain hemlock

16 Dendroglaciology Results Terminal Terminal Moraine years (1813) Upper Upper Recessional Moraine years (1903) Lateral Lateral Moraine 97 years (1910)

17 Methods: Dendrochronology The Girls Cored all trees large enough to core Counted whorls of smaller trees Cut down two trees to determine whorl counting accuracy Cut down two scarred treed Used an oblique photo from 1897 to determine ecesis interval

18 Oblique photo showing glacial extent in 1897

19 Dendroglaciology Results The The oldest tree on the lower moraine was 112 years old and the oldest tree on the upper moraine was 31 years old. Ecesis: Ecesis: years Lower Moraine Age: years old ( ) Upper Moraine Age: years old ( ) 1907)

20 Dendrogeomorphology Results There There were two visible scars on both cut trees. They revealed that disturbances (probably avalanches) occurred 12 and 26 years ago.

21 Dendroclimatology Results Three Three distinct germination periods were found by counting seedling whorls: years ago (1973) years ago (1981) years ago (1992)

22 Revelstoke Climate Data and seedling germination

23 Final Cumulative Results Final Final East Asulkan Map.

24 Final Cumulative Results

25 How do we stack up to 2007??? Anastasiades et al. (2007). Terminal Moraine Mid-Recessional Moraine Upper-Recessional Moraine Demidow et al. (2008). Terminal Moraine Lower Recessional Moraine Upper Recessional Moraine

26 Visual Comparison

27 Sources of Error Data Data Collection Height of trees and lichen Aspect of trees and lichen Too many cooks in the kitchen!

28 Sources of Error Ecesis Ecesis and Growth Curves Anastasiades et al. (2007) based their ecesis on a lichen growth curve from Luckman (1977), based in Jasper National Park. This study is based on McCarthy (2003) s s lichen growth curve based on the Illecillewaet glacier. Same Date, Smaller Lichen. Difference?? Moisture Regime. Jasper, Alta. (Mt. Edith Cavell) 394 mm/year Precipitation Golden, BC. (Illecillewaet) 950 mm/year Precipitation

29 Potential Environmental Proximity to streams Natural disturbances Topography Rock type Differences

30 Conclusion Lichenometry and Dendrochronology are effective methods of dating moraine ridges in glacial environments. Growth Growth curves and ecesis rates are spatially variable and regionally independent.

31 Thank-You! Thanks Thanks to Dan, Jim, Bethany, Sarah, Kate, and Lynn for sharing your knowledge and passion of the alpine.