Holocene relative sea-level changes in the inner Bredefjord area, southern Greenland

Charlotte J. Sparrenbom, Ole Bennike, Daniel Fredh, Linda Randsalu-Wendrup, Dan Zwartz, Karl Ljung, Svante Björck, Kurt Lambeck

Publikation: Bidrag til tidsskriftArtikelForskningpeer review

13 Citationer (Scopus)

Abstrakt

In this paper we present new relative sea-level data from southern Greenland, a key area for understanding the Greenland Ice Sheet (GIS) response to climate change. Within fourteen lakes and marine lagoons from the inner part of Bredefjord (Nordre Sermilik) in southern Greenland, isolations revealed by stratigraphic and palaeoecological analyses are dated and relative sea levels reconstructed. Due to coastal emergence caused by the GIS retreat within the area, the relative sea-level fell rapidly in the early Holocene between at least c. 9600 and c. 7300 cal yrs BP attaining a rate of 2cm per year between 9600 and 8000 cal yrs BP. Spatial variability in relative sea-level changes is show for southern Greenland from a comparison with the Nanortalik and the Qaqortoq areas. The regression occurred about 2000 years later in the inner Bredefjord area, compared to the Nanortalik area, and about 1000 years later compared to the Qaqortoq area. This is a consequence of earlier deglaciation in areas located at the outer coast. Between c. 8000 cal yrs BP and the present day, relative sea level was lower than today. The lowest relative sea level in the Inner Bredefjord area of between-5.4 and-15m a.h.a.t. (above highest astronomical tide) was reached between 7000 and 1000 cal yrs BP. The neoglacial readvance together with the collapse of the Laurentide peripheral bulge is probably responsible for the transgression in the Inner Bredefjord area, as has been indicated from the nearby sites Qaqortoq and Nanortalik. Our relative sea-level reconstructions showing spatial variability within southern Greenland have implications for Glacial Isostatic Adjustment (GIA) modelling and the understanding of the GIS ice sheet dynamics. The early Holocene regression is consistent with the recession of the southern sector of the GIS from the shelf edge at c. 22000 cal yrs BP, reaching inland of the present day outer coast by c. 12000 cal yrs BP, and its present margin by c. 10500 cal yrs BP.

OriginalsprogEngelsk
Sider (fra-til)107-124
Antal sider18
TidsskriftQuaternary Science Reviews
Vol/bind69
DOI
StatusUdgivet - 1 jun. 2013

Programområde

  • Programområde 5: Natur og klima

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