David A. Fisher, Roy M. Koerner, Jocelyne C. Bourgeois, Greg Zielinski, Cameron Wake, Claus U. Hammer, H. B. Clausen, N. Gundestrup, Sigfus Johnsen, Kumiko Goto-Azuma, Takeo Hondoh, Erik Blake, Mike Gerasimoff

Ice cores from Penny Ice Cap, Baffin Island, Canada, provide continuous Holocene records of oxygen isotopic composition (¹⁸O, proxy for temperature) and atmospheric impurities. A time scale was established with the use of altered seasonal variations, some volcanic horizons, and the age for the end of the Wisconsin ice age determined from the GRIP and GISP2 ice cores. There is pre-Holocene ice near the bed. The change in ¹⁸O since the last glacial maximum (LGM) is at least 12.5 per mil, compared with an expected value of 7 per mil, suggesting that LGM ice originated at the much higher elevations of the then existing Foxe Dome and Foxe Ridge of the Laurentide Ice Sheet. The LGM ¹⁸O values suggest thick ice frozen to the bed of Hudson Bay.

D. A. Fisher, R. M. Koerner, J. C. Bourgeois, Terrain Sciences Division, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, Canada.
G. Zielinski and C. Wake, Glacier Research Group, Morse Hall, University of New Hampshire, Durham, NH 03824-3525, USA.
C. U. Hammer, H. B. Clausen, N. Gundestrup, S. Johnsen, Niels Bohr Institute, Department of Geophysics, University of Copenhagen, Rockefeller Complex, Juliane Maries Vej 30, Copenhagen , Denmark DK-2100.
K. Goto-Azuma, Nagaoka Institute of Snow and Ice Studies, 187-16 Suyoshi-machi, Nagaoka-shi, Niigata-ken 940, Japan.
T. Hondoh, Institute of Low Temperature Science, Hokkaido University, Sapporo 060, Japan.
E. Blake and M. Gerasimoff, Icefield Instruments, 3 Glacier Drive, Unit 2, Whitehorse, Yukon Y1A 5H4, Canada.