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Two deep ice cores from central Greenland, drilled in the 1990s, have played a key role in climate reconstructions of the Northern Hemisphere, but the oldest sections of the cores were disturbed in chronology owing to ice folding near the bedrock. Here we present an undisturbed climate record from a North Greenland ice core, which extends back to 123,000 years before the present, within the last interglacial period. The oxygen isotopes in the ice imply that climate was stable during the last interglacial period, with temperatures 5°C warmer than today. We find unexpectedly large temperature differences between our new record from northern Greenland and the undisturbed sections of the cores from central Greenland, suggesting that the extent of ice in the Northern Hemisphere modulated the latitudinal temperature gradients in Greenland. This record shows a slow decline in temperatures that marked the initiation of the last glacial period. Our record reveals a hitherto unrecognized warm period initiated by an abrupt climate warming about 115,000 years ago, before glacial conditions were fully developed. This event does not appear to have an immediate Antarctic counterpart, suggesting that the climate see-saw between the hemispheres (which dominated the last glacial period) was not operating at this time. [ABSTRACT FROM AUTHOR]

Reports on evidence of past volcanism found in the ice core recovered at Byrd Station Antarctica in 1968. Establishment of three major conditions of volcanic chronology; Continuous acidity curves for several representative depth levels; Chronological record of 57 major high-acid volcanic signals measured from the present back to 50 ka BP.

Presents results from a new deep ice core drilled at the summit of the Greenland ice sheet. Depositional environment and flow pattern of the ice that are ideal for core recovery and analysis; Obtaining high-resolution continuous time series of climate-related parameters; Interstadial episode; Ice core data, including ice-sheet thickness, accumulation rate and mean air temperature; More.