The first Holocene relative sea‐level curve from the middle part of Hardangerfjorden, western Norway

Abstract

Romundset, A., Lohne, Ø. S., Mangerud, J. & Svendsen, J. I. 2009: The first Holocene relative sea‐level curve from the middle part of Hardangerfjorden, western Norway. Boreas, 10.1111/j.1502‐3885.2009.00108.x. ISSN 0300‐9483.The first relative sea‐level (RSL) curve from the mid‐Hardangerfjorden area covering the entire Holocene is presented. The curve is based on a series of AMS 14C dates on terrestrial plant macrofossils across the isolation level in each of five lakes located between 3.5 and 74.5 m a.s.l. During the first 1200 years, the RSL fell very rapidly from the marine limit at 98 m a.s.l. to 33 m a.s.l., i.e. at a rate of 5.4 cm yr−1. The emergence rate then slowed considerably and was close to standstill 8000–6500 cal. yr BP. However, an emergence of 16.5 m has taken place during the past 6000 years. Radiocarbon dates of terrestrial plant macrofossils from the basal strata in a lake above the marine limit and mollusc shells from glaciomarine silt in the isolation basins yielded a mean age for the local ice‐margin retreat of 11 300 cal. yr BP. This verifies that Hardangerfjorden was glaciated during the Younger Dryas – an interpretation that has recently been disputed. The ice margin retreated at a rate of about 300 m yr−1 from the position of the Younger Dryas moraine to this site some 60 km further into the fjord.