Penny Ice Cap cores, Baffin Island, Canada, and the Wisconsinan Foxe Dome connection: Two states of Hudson Bay ice cover

Science

Volumn 279, Issue 5351, 1998, Pages 692-696

  Fisher, David A ^a   Koerner, Roy M ^a   Bourgeois, Jocelyne C ^a   Zielinski, Greg ^b   Wake, Cameron ^b   Hammer, Claus U ^c   Clausen, H B ^c   Gundestrup, N ^c   Johnsen, Sigfus ^c   Goto Azuma, Kumiko ^d   Hondoh, Takeo ^e   Blake, Erik ^f   Gerasimoff, Mike ^f  

^a GEOLOGICAL SURVEY OF CANADA   (Canada)

^b UNIVERSITY OF NEW HAMPSHIRE   (United States)

^c UNIVERSITY OF COPENHAGEN   (Denmark)

^d Nagaoka Inst of Snow and Ice Studs   (Japan)

^e HOKKAIDO UNIVERSITY   (Japan)

^f Unit 2   (Canada)

Author keywords

[No Author keywords available]

Indexed keywords

ICE;

HOLOCENE; ICE CORE; ISOTOPIC COMPOSITION; OXYGEN;

ARTICLE; GEOGRAPHY; PRIORITY JOURNAL; SEASONAL VARIATION; TIME;

CANADA, HUDSON BAY; CANADA, NORTHWEST TERRITORIES, BAFFIN ISLAND;

EID: 6844255205     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.279.5351.692     Document Type: Article

References (42)

1. A. S. Dyke and V. K. Prest, "Paleogeography of Northern North America 18000-5000 Years Ago," Geol. Surv. Can. Map 1703A (1987)
2. D. A. Fisher, N. Reeh, K. Langley, Geogr. Phys. Quat. 39, 229 (1985).
3. A. S. Dyke, Arct. Alp. Res. 11, 179 (1979).
4. The melt percent is that of the bubble-free ice after correction is made for density differences. Bubble-free ice is formed by summer melt that subsequently refreezes in the firn (31), which contains more air bubbles.
5. 16O], the square brackets denoting number concentration, and SMOW being standard mean ocean water.
6. W. Dansgaard, S. J. Johnsen, H. B. Clausen, N. Gundestrup, Meddelelse Grønland 197 (no. 2), 53 (1973).
7. D. A. Fisher, Cold Reg. Sci. Technol. 21, 61 (1992).
8. H. B. Clausen et al., in Ice Core Studies of Global Biogeochemical Cycles, R. J. Delmas, Ed. (NATO ASI Ser. I 30, Springer-Verlag, Berlin, 1995), pp. 175-194.
9. C. Wake, G. A. Zielinski, N. Grumet, in preparation.
10. S. R. O'Brien, Science 270, 1962 (1995).
11. 18O value. From automatic weather station (AWS) (Fig. 1B) data, the present mean air temperature is -16.6°C.
12. G. Robin de Q, J. Glaciol. 2, 523 (1955).
13. 18O are removed until the remaining accumulation at P95 is equal to P96.
14. D. A. Fisher, R. M. Koerner, N. Reeh, Holocene 5, 19 (1995).
15. G. A. Zielinski et al., Science 264, 948 (1994); ibid. 267, 257 (1995).
16. G. A. Zielinski et al., Science 264, 948 (1994); ibid. 267, 257 (1995).
17. J. Zheng et al., Holocene, in press.
18. C. U. Hammer et al., J. Glaciol. 20, 3 (1978).
19. S. Jonsson and M. E. Hansson, Geogr. Ann. Ser. A 72, 41 (1990).
20. R. B. Alley et al., Nature 362, 527 (1993); S. J. Johnsen et al., ibid. 359, 311 (1992). Even though the sampling interval for ECM data is 1 mm, the effect of electrode spacing tends to produce a moving average of the conductivity, thus reducing the true resolution. This effect is partly offset by the electrons preferring the highest conductive layers. There is thus a tendency for such an approach to overestimate layer thickness near the limits of resolution. This is in fact what we find.
21. R. B. Alley et al., Nature 362, 527 (1993); S. J. Johnsen et al., ibid. 359, 311 (1992). Even though the sampling interval for ECM data is 1 mm, the effect of electrode spacing tends to produce a moving average of the conductivity, thus reducing the true resolution. This effect is partly offset by the electrons preferring the highest conductive layers. There is thus a tendency for such an approach to overestimate layer thickness near the limits of resolution. This is in fact what we find.
22. J. F. Nye, J. Glaciol. 3, 493 (1959); D. A. Fisher, thesis, University of Copenhagen (1977).
23. J. F. Nye, J. Glaciol. 3, 493 (1959); D. A. Fisher, thesis, University of Copenhagen (1977).
24. D. A. Fisher, N. Reeh, H. B. Clausen, Ann. Glaciol. 7, 76 (1985).
25. D. A. Fisher and R. M. Koerner, J. Glaciol. 32, 501 (1986).
26. D. A. Fisher, in The Physical Basis of Ice Sheet Modelling, E. D. Waddington and J. S. Walder, Eds. (Int. Assoc. Hydrol. Sci. Publ. 170, IAHS Press, Wallingford, Oxfordshire, UK, 1987), pp. 45-50.
27. W. S. B. Paterson et al., Nature 266, 508 (1977).
28. D. A. Fisher and B. T. Alt, Ann. Glaciol. 7, 117 (1985).
29. S. J. Johnsen, in Isotopes and Impurities in Snow and Ice (Int. Assoc. Hydrol. Sci. Publ. 118, IAHS Press, Wallingford, Oxfordshire, UK, 1977), pp. 388-392.
30. R. LeB Hooke and H. B. Clausen, Geol. Soc. Am. Bull. 93, 784 (1982).
31. S. J. Johnsen et al., J. Geophys. Res., in press; R. B. Alley et al., Nature 373, 393 (1995).
32. S. J. Johnsen et al., J. Geophys. Res., in press; R. B. Alley et al., Nature 373, 393 (1995).
33. M. E. Hansson, Tellus B 46, 390 (1994).
34. A. Neftel et al., in Greenland Ice Core: Geophysics, Geochemistry, and the Environment, C. C. Langway Jr., H. Oeschger, W. Dansgaard, Eds. (Geophys. Monogr. 33, American Geophysical Union, Washington, DC, 1985), pp. 32-38.
35. R. M. Koerner and D. A. Fisher, Nature 343, 630 (1990).
36. D. A. Fisher, in The Last Deglaciation: Absolute and Radiocarbon Chronologies, E. Bard and W. S. Broecker, Eds. (NATO ASI Ser. 12, Springer-Verlag, Berlin, 1992), pp. 267-293.
37. 18O records in this interval are too negative (that is, isotopically cold), which may be due to early Holocene ice that formed from very negative source ocean water "spiked" by melt water from the melting Laurentide Ice Sheet (32).
38. 18O changes into elevation changes. Also, the elevation changes implied by the value of -0.2 per mil per 100 m are unrealistic.
39. J. J. Johnsen, D. Dahl-Jensen, W. Dansgaard, W. N. Gundestrup, Tellus B 47, 624 (1995); K. M. Cuffey et al., Science 270, 455 (1995).
40. J. J. Johnsen, D. Dahl-Jensen, W. Dansgaard, W. N. Gundestrup, Tellus B 47, 624 (1995); K. M. Cuffey et al., Science 270, 455 (1995).
41. M. Ters, in Climate History, Periodicity and Predictability, M. R. Rampiro, J. E. Sanders, W. S. Newman, L. K. Königsson, Eds. (Van Nostrand Reinhold, New York, 1987), pp. 205-237.
42. We thank N. Grummet, J. Sekerka, and M. Parnandi for their work in the field and lab preparing and measuring samples and L. Peplinski for infrastructure and radio support in Iqaluit. The Polar Continental Shelf Project of the Ministry of Natural Resources Canada provided aircraft and logistic support to the Penny work. Y. Bossé of Parks Canada made our work in Auyuittuq National Park possible through his help and cooperation. Finally, the mayors and people of the towns of Iqaluit, Pangnirtung, and Broughton were most helpful, supportive, and interested in our work.