| Title | The Last Glacial Maximum |
| |
| Author | Clark, P U; Dyke, A S; Shakun, J D; Carlson, A E; Clark, J; Wohlfarth, B; Mitrovica, J X; Hostetler, S W; McCabe, A M |
| Source | Science vol. 325, no. 5941, 2009 p. 710-714, https://doi.org/10.1126/science.1172873 |
| Links | Supplementary Data
|
| Year | 2009 |
| Alt Series | Earth Sciences Sector, Contribution Series 20080591 |
| Publisher | American Association for the Advancement of Science (AAAS) |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | html; pdf (Adobe® Reader®) |
| Area | Arctic; Antarctic; North America; Europe; Tibet; Tropics; Sub-Tropics; Southern Hemisphere |
| Lat/Long WENS | -180.0000 180.0000 90.0000 -90.0000 |
| Subjects | surficial geology/geomorphology; environmental geology; Pleistocene; Holocene; geological history; glacial history; glaciation; deglaciation; climate; climatic fluctuations; climatology; radiometric
dating; helium isotopes; carbon isotopes; glaciers; ice sheets; sea level changes; Cordilleran Ice Sheet; Innuitian Ice Sheet; Laurentide Ice Sheet; West Antarctic Ice Sheet; East Antarctic Ice Sheet; Antarctic Peninsula Ice Sheet; Barents-Kara Ice
Sheet; Greenland Ice Sheet; British-Irish Ice Sheet; Scandinavian Ice Sheet; Phanerozoic; Cenozoic; Quaternary |
| Illustrations | location maps; time series |
| Program | Enhancing resilience in a changing climate |
| Released | 2009 08 06 |
| Abstract | The Last Glacial Maximum (LGM) is conventionally defined as the most recent interval in Earth history when global ice sheets reached their maximum integrated volume (1) (Fig. 1). More than 30 years
ago, CLIMAP used then-existing stratigraphic information to infer that the LGM occurred 18,000 14C years ago (now known to be 21,000 calendar years ago), an age that remains in wide use today (2). This singular age implies that the LGM was a
transient feature in Earth history, and that ice sheets never reached an equilibrium state with the climate system. More recent reconstructions of global sea level, however, suggest that the LGM persisted for several thousand years (3-5),
corresponding to an extended interval of relatively stable climate (1). Because sea level is an integrated signal, however, it does not distinguish between globally synchronous ice-sheet maxima that may have been in equilibrium throughout this
interval from temporally variable regional ice-sheet maxima that combined to produce a millennia-long sea-level lowstand.
Here we use existing relative sea level (RSL) data from far-field sites to constrain the timing of the LGM as occurring
from 26,000 to 19,000 years ago (26-19 ka). We then draw upon ~4200 14C ages and ~500 cosmogenic surface exposure ages (CSEAs) that span the interval from 10-50 ka to constrain the timing of maxima in global ice-sheet extent (Fig. 1). For all but
the Barents-Kara Ice Sheet, the spatial distribution of ages is sufficient to evaluate regional variability in the timing of maxima for different sectors of individual ice sheets. Because ice-sheet extent scales with ice volume (6), our constraints
on regional variability in ice-sheet maxima allow us to directly evaluate the temporal evolution of individual ice-sheet contributions to global sea-level change. |
| GEOSCAN ID | 226276 |
|
|