As many as 44 shell samples from deposits within end moraines and from glaciomarine deposits related to end moraines were used to radiocarbon date 5 morainal zones in Nordland. Zone A, Vega-Skarpnes Event, 12,300?200 years B.P. Zone B, Tj0tta-Troms0-Lyngen Event, 10,700?300 years B.P. Zone C, Nordli-Skjerstad Event, 10,100+200 years B.P. Zone D, Misvaer-Finneid Event, 9550?200 years B.P. Zone E, Rombak-0lfjell Event, 9300+200 years B.P. Introduction Altogether 46 shell samples collected by the writers from deposits related to marginal moraines in Nordland and southernmost Troms have been radiocarbon dated at Trondheim Radiological Dating Laboratory. The dates of as many as 39 of the samples correspond approximately with the expected ages. Seven samples must have been contaminated since their radiocarbon ages are obviously much too high or too low. On the basis of the 39 "correct" dates and 5 dates of samples collected by other scientists the excact radiocarbon ages of the moraines were determined. They were grouped into 5 major marginal moraine zones, A to E, which will be described in the following (cf. Figs. 1 and 3). The dated moraines were deposited in the sea and raised above sea level in post glacial time. Located above sea level the interior structure of the moraines and the corresponding sediments adjacent to the moraines can more easily be studied. Fig. 2 shows a generalized cross-section of a marinely deposited terminal moraine. The presented stratigraphical units vary in thickness in the different moraines, but the lithology of each unit is much the same in all moraines. Units Y1-Y3 are younger than the moraine, Mi-M6 correspond with the moraine and units 0,-02 are 1 Department of Geology, University of Bergen 2 Oljedirektoratet, Stavanger 3 Radiological Dating Laboratory, Trondheim older than the moraine. In situ marine shells in the beds correspond in age with the host sediment and can be used to date the different depositional phases. Transported shells, in general fragments, are usually older than the host sediment, and their radiocarbon dates represent maximum ages of the beds. Of particular interest are the M units which represent the end moraine and corresponding deposits. Most of the dated shells were found within the M units, and many within the glaciomarine beds M6 on the distal side of the moraine. The M6 unit is very thick at the moraine, and the thickness decreases quickly in distal direction. The lithology varies from gravelly clay with dropstones to bouldery gravel. Gravelly clay is most usual and the gravel/boulder content is highest near the moraines. Units Ml, M2 and M5 frequently contain transported shell fragments which are older than the moraine. High-arctic molluscan faunas which thrived in the cold, muddy and often brackish water near the ice fronts are usually found in unit M6. Due to the rapid sedimentation of clay near the ice fronts the shells lie scattered in the clay, and it is usually very time-consuming to collect enough shells for radiocarbon dating. Different faunas seem to be related to the different glacier events. A very distinctive Main-Arctic shore line was formed during the B-event. Shore lines which correspond with the younger events lie below the Main-Arctic shore line, and higher lying shore lines correspond with older events. The oldest moraines Several moraines on the Lofoten Islands (M0ller & Sollid 1972) are older than the A-event. They are not precisely dated. However, radiocarbon dates at about 18,000 years B.P. of lacustrine sediments at And0y Island (K. D. Vorren, 1978) together with radiocarbon dated marine beds on the shelf near And0y (T. Vorren, 1981) suggest that the age of the oldest moraines could be 18,000 to 20,000 years B.P. Geografiska Annaler ? 63 A (1981 ) 3-4 155 This content downloaded from 157.55.39.111 on Wed, 03 Aug 2016 05:40:11 UTC All use subject to http://about.jstor.org/terms BJ0RN G. ANDERSEN, FREDE B0EN, REIDAR NYDAL, ARNE RASMUSSEN AND PAL VALLEVIK