Late Pleistocene, Holocene and present sea-levels: constraints on future change
Late Pleistocene and Holocene sea-levels exhibit considerable t mporal and spatial variation around the globe when compared with present-day sea-levels. This is the result of volumetric changes of the ocean produced by the melting of the Pleistocene ice sheets, the response of the crust o these redi...
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| Format: | Text |
| Language: | English |
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1990
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.458.437 http://people.rses.anu.edu.au/lambeck_k/pdf/132.pdf |
| Summary: | Late Pleistocene and Holocene sea-levels exhibit considerable t mporal and spatial variation around the globe when compared with present-day sea-levels. This is the result of volumetric changes of the ocean produced by the melting of the Pleistocene ice sheets, the response of the crust o these redistributed surface loads, and to tectonic movements of the shore lines of other than glacio-hydro-isostatic origin. By examining the sea-level records from geographically well-distrib-uted areas over time spans covering the past 10,000 years, and by avoiding records from tectonically unstable regions, it becomes possible to effect a separation of the major parameters contributing to the sea-level change. Geomorphological observations ofsea-level change at sites far from the former ice sheet margins provide constraints on the total volume of Late Pleistocene meltwater and on the rate at which this meltwater has been added into the oceans. The Laurentide and Fennoecandian icesheets appear to have been inadequate o explain the observed sea-level rise of about 130 m from 18,000 to 6000 years ago. Some contribution (--10-15 m) from the Barents-Kara seas may have occurred as well. Antarctic ontributions to the rise in sea-level appear to have been important and occurred at about he same time as or slightly after the Arctic ice sheet decay. The Antarctic melting continued, at slow rates, up to the present. Tide gauge records over the past few decades also exhibit spatial variations inthe rates of increase. The global average is about 1.2 nun/year but a pronounced zonal variation also occurs. About 50 % of the global average rise may be the result of on-going melting of mountain and Antarctic glaciers and part of the spatial variation is the result of the ongoing |
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