Ice Age Paleotopography

Abstract

A gravitationally self-consistent theory of postglacial relative sea level change is used to infer the variation of surface ice and water cover since the Last Glacial Maximum (LGM). The results show that LGM ice volume was approximately 35 percent lower than suggested by the CLIMAP reconstruction and the maximum heights of the main Laurentian and Fennoscandian ice complexes are inferred to have been commensurately lower with respect to sea level. Use of these Ice Age boundary conditions in atmospheric general circulation models will yield climates that differ significantly from those previously inferred on the basis of the CLIMAP data set.

A paleotemperature record derived from dissolved noble gases in groundwater of the Aquia Aquifer (Maryland, USA)

“…The temperature change of 9.0°C found at our study site is clearly larger than the results from previous noble gas studies in the USA: New Mexico: 5.5°C (Stute et al, 1995a), Colorado: 5°C (Clark et al, 1998), Texas: 5.2°C (Stute et al, 1992a), Georgia: 4°C (Clark et al, 1997). The extension of the ice sheet at 18 kyr BP is shown for comparison (Peltier, 1994).…”

“…The large Holocene -LGM temperature difference at our study site is probably due to the influence of the Laurentide ice sheet, which at its maximum extension reached as close as 250 km to the study site (using the ice-sheet reconstruction of Peltier, 1994). Climate models (Manabe and Broccoli, 1985;COHMAP, 1988;Bartlein et al, 1998) indicate major reorganizations of the circulation over North America in response to the Laurentide ice sheet, in particular a southward displacement or even a split of the jet stream and the development of a glacial anticyclone over the ice sheet.…”

On the reconstruction of palaeo-ice sheets: Recent advances and future challenges

“…The ICE-NG series of deglacial ice load reconstructions (Tushingham and Peltier, 1992 (ICE-3D); Peltier, 1994;1996 (ICE-4G) ;Peltier, 2004 (ICE-5G)) have been the most widely used examples of the GIA-based approach. The most recent model in this series, ICE-6G_C (VM5a), uses the largest set of space geodetic constraints currently available to both constrain and validate the reconstruction (Argus et al, 2014;Kierulf et al, 2014;Peltier et 41 al., 2015).…”

Mangrove pollen of Indonesia and its suitability as a sea-level indicator

“…At the last glacial maximum (LGM), sea-level was reported to be 120m lower in Barbados based on coral terraces (Fairbanks 1989), 135m lower in the Bonaparte Gulf, Australia (Yokoyama et al 2000) thpugh this figure has been challenged by Shennan and Milne (2003 ), 117. 8m lower through modelled predictions (Peltier 2002) and 1 05m lower based on tectonic corrections (Peltier 1994) than at the present day. There is however good agreement between the timings of the sea-level minima with Fairbanks and Yokoyama indicating a sea-level of -120m at 19,000 cal yr. BP in Barbados and the Bonaparte Gulf respectively.…”