NJG78-1-03
1998
The Norwegian strandflat - a geomorphological puzzle
78
1
pp. 47-66

The strandflat between Karmøy and Bodø has been geomorphologically analysed, primarily on the basis of constructed hypsographical curves. By this method, height conditions and the maturity of the strandflat have been estimated. The general level of the strandflat is to a great extent related to the Late Weichselian marine limits along the coast from Karmøy to Frøya/Hitra, indicating a formation, closely connected to glacial isostasy, but with increasing maturity, reaching a maximum in the Smøla island area. Along the Helgeland coast, there is great discrepancy in height between the high Late Weichselian marine limits and the level of the low, and very mature, partly submerged strandflat. The horizontality of the Helgeland strandflat, and the peripheral parts of the strandflat farther south, must be due to denudation during stages of crustal stability, i.e. during interglacials or interstadials. The strandflat is polycyclic, and remnants of higher levels are present dose to the backwall in many areas, and also at some distance inside the fjords. The strandflat was most likely formed in Late Pliocene/Pleistocene times, i.e. during the last 2.57 Ma. It is thought to be a product of glacial erosion, marine erosion and subaerial weathering, where frost processes have played an important part. Conditions similar to the Late Weichselian must have been particularly favourable for the strandflat-forming processes. The pre-strandflat palaeo-surface has been reconstructed, and in some coastal areas where it nearly coincides with the present strandflat surface, the strandflat may represent an exhumed pre-Jurassic surface.

H. Holtedahl, Department of Geology, University of Bergen, N-5007, Bergen, Norway.

0029-196X