1. Tracking the Laurentide – On the trail of the last great ice sheet

2. Deglaciation – a lot of melt water
Deglaciation – a lot of melt water. The terrestrial record of glacial meltwater

3. Con Mine, Yellowknife, Canada:
Glacial meltwater
in the
Canadian Shield
Con Mine, Yellowknife, Canada:
Clark, I.D., Douglas, M., Raven, K. and Bottomley, D.J., Recharge and preservation of glacial meltwater in the Canadian Shield. Ground Water, 38:

4. Con Mine,
Yellowknife

9. Geochemistry of groundwaters

10. Groundwaters Cl– (mg/L) d18O ‰ VSMOW -30 -25 -20 -15 -10 1 10 100 1000
10,000
100,000
1,000,000
-30
-25
-20
-15
-10
d18O ‰ VSMOW

11. Modern Glacial Cl– (mg/L) meltwater ? Brine d18O ‰ VSMOW10
Modern
100
Glacial
meltwater ?
Cl– (mg/L)
1000
Modern – Brine
binary mixing line
10,000
Brine
100,000
-30
-25
-20
-15
-10
d18O ‰ VSMOW

12. How to recharge glacial meltwater . . .
Late Pleistocene time:
Laurentide Ice Sheet
Shield brine in bedrock

13. Early Holocene deglaciation:

14. Mid to late Holocene:

15. Mining activities:

16. Finite difference modelling with SWIFT II
Stationary margin of
Laurentide ice sheet
Proglacial Lake McConnell
2000
1000
Salinity gradients after 50 yrs
Depth (m)
50% brine
60% brine
70% brine
80% brine
90% brine
Distance (km)

17. Con Mine,
Yellowknife
East Bull
Lake

18. d2H d2H d18O d18O d2H d2H d18O d18O East Bull Lake Ottawa Chalk River
-120
-100
-80
-60
-130
-110
-90
-70
-120
-100
-80
-60
d2H
d2H
East Bull Lake
Ottawa
d18O
d18O
-17
-15
-13
-11 -9
d2H
d2H
Chalk River
Trois Rivières
d18O
d18O
-17
-15
-13
-11 -9

19. Source: GSC

20. Deep Geologic Repository for Nuclear Waste

22. d18O in formation pore waters
glacial
meltwater
basin
brine

25. Glacial Meltwater

26. The Younger Dryas Cold Period