Holocene Climatic Records From Antarctic Ice

Abstract

The climate of the Holocene is, for continental regions from middle and low latitudes, relatively well documented from pollen studies and other sources. To obtain a global picture, these data must be supplemented by climatic series from polar regions. Such information may be extracted from δD or δ18O ice-core profiles but the interpretation of these isotopic records suffers some limitations, (1) because, expected temperature changes being small, they can be obscured by noise effects in the isotope-temperature relationship, and (2) because they can be influenced, especially in coastal regions, by changes in origin of the ice.With this in mind, we focus our presentation on Dome C and Vostok cores drilled on the East Antarctica Plateau and essentially undisturbed by ice-flow conditions. The detailed comparison between these continuous isotopic records makes it possible to know which part of the isotopic signal is climatically significant. Spectral properties of these two records are also examined over the Holocene period. In addition, we present isotopic results obtained on a 950 m ice core drilled at Komsomolskaia (also on the East Antarctica Plateau) by the Soviet Antarctic Expedition. This core fully covers the Holocene and, although discontinuous, the new data help us to document the East Antarctica isotopic record.From these data, an average climatic record is constructed which shows that the East Antarctica climate was fairly stable during the Holocene, marginally warmest around 10 kyear B.P. and coldest in periods around 1.5 and 6 kyear B P. These features are discussed in relation with other Antarctic data (Byrd, Law Dome, Ross Ice Shelf) and with climate records from both southern and northern hemispheres

A Comparison of Deep Antarctic Ice Cores and Their Implications for Climate Between 65,000 and 15,000 Years Ago

“…The Dome C and Vostok temperature records compare quite well over all of the last 40,000 yr, in terms of glacialinterglacial changes (-9"C), the nature of last deglaciation, and as discussed above and directly relevant to this work, for the last glacial period. However, a slight difference exists in the timing of the cold reversal within the last transition which occurs a few hundred years earlier at the Dome C than at Vostok; this point together with a detailed comparison of the Antarctic Holocene ice records, will be fully discussed elsewhere (Petit et al,, 1987b;J. R. Petit et al, unpublished data).…”

Terrigenous Sediment Supply in the Polar to Temperate South Atlantic: Land-Ocean Links of Environmental Changes during the Late Quaternary

“…However, this suggestion is not well supported by provenance analyses taking into account the mineralogical and geochemical composition (major and trace elements, neodymium and strontium isotopes) of marine muds (Bareille et al 1994;Diekmann et al 2000;Walter et al 2000). Clues for stronger atmospheric dust fluxes during glacial times actually arise from increased dust concentrations ofPatagonian origin in the ice cores from the East Antarctic ice sheet (Petit et al 1990;Grousset et al 1992). The Vostok dust record for example suggests greater dust fluxes by a factor between 15 and 25 for the last glacial maximum (petit et al 1990;Mahowald et al 1999).…”

“…Clues for stronger atmospheric dust fluxes during glacial times actually arise from increased dust concentrations ofPatagonian origin in the ice cores from the East Antarctic ice sheet (Petit et al 1990;Grousset et al 1992). The Vostok dust record for example suggests greater dust fluxes by a factor between 15 and 25 for the last glacial maximum (petit et al 1990;Mahowald et al 1999). However, in relation to the low present-day dust fluxes over the Southern Ocean (Duce et al 1991;Husar et al 1997), dust fluxes were too low even during glacial times to strongly affect the observed MARTs in the Southern Ocean (Bareille et al 1994;Maher and Dennis 2001).…”