Late Quaternary history around Nioghalvfjerdsfjorden and Jokelbugten, North-East Greenland

Nioghalyfjerdsfiorden in North-East Greenland is at present covered by a fl oating glacier. Raised marine deposits in the surrounding area contain shel ls of marine molluscs, bones of marine mammals and piece, of driftwood. A f airly systematic sampling of such material has been conducted, followed by extensive radiocarbon dating. We suggest that the Greenland ice sheet exten ded onto the shelf offshore North-East Greenland during isotope stage 2, pe rhaps even reaching the shelf break. During the subsequent recession of the ice sheets the entrance of Nioghalvfjerdsfjorden had become ice-free by 9. 7 cal. ka FIR The recession culminated between 7.7 and 4.5 cal, ka BP. duri ng A which time the fjord was glacier-free along its entire 80 km length. N o dates younger than 4.5 cal. ka BP are available on marine material from t he fjord, and it seems probable that the fjord has been continuously cohere d by the floating glacier since this time. The maximum glaciation was attai ned around AD 1900. after which thinning and recession took place. The mari ne limit increases front c. 40 m above sea level near the present margin of the Inland Ice to c. 65 m above sea level at the outer coast. These figure s fit into the regional pattern of the marine limit for areas both to the s outh and north, The marine fauna comprise two bivalves, Macoma (calcarea an d Serripes groenlandicus. that may represent a Southern element present dur ing the Holocene temperature optimum. Remains of three taxa of southern ext ralimital terrestrial and limnic plants were dated to 5.1 cal. kit BP, and remains of another extralimital plant were dated to 8.8 and 8.5 cal. ka BP. The known Holocene time ranges of the willow Salix arctica and the lemming Dicrostonyx torquatus ha c been extended back to 8.8 and 6.4 cal. ka BP. r espectively, providing minimum date, for their immigration to Greenland.