NJG72-4-02
1992
Sedimentology and stratigraphy of two glacial-deglacial sequences at Skorgenes,western Norway
72
4
pp. 357-368

Two complex sequences of diamictons and associated waterlain deposits were investigated with respect to processes of formation. The Jowest unit, a highly variable deposit ranging from clay to diamicton and with an overall upward coarserung trend, is interpreted as a series of subaqueous ftows from a glacial source. Based on a number of characteristics, such as rip-up clasts and deformed sand lenses, the overlying diamicton is interpreted as a result of a combination of processes between melt-out and lodgement till. Ice-flow directions change from regional to local up the unit. Between this till and the next diamicton unit, lie bottomset and foreset beds of a delta, most likely glaciomarine, and deposited when sea level was minimum 84 m. The upper diamicton is also interpreted as a combination of melt-out and lodgement, but is probably doser to the melt-out end member than the lower diamicton. Only local ice flow directions are recorded in till fabrics, but thrust faults and strong overconsolidation of underlying sediments evidence thick ice independent of topography overriding the site. The entire section is capped by a glaciomarine delta deposited up to the marine limit (90 m) during the last deglaciation. Thermoluminescence and optical stimulated dates were obtained from the waterlain sediments. The results from parallel dating are highly variable. However, based on these┬ádates and correlations with a welldated sequence in the cave Skjonghelleren, it is proposed that the upper diamicton was deposited during the Weichselian maximum, the underlying delta during the ├ůlesund interstadial (ca. 30 ka BP), and the lower diamicton during a glacial advance some 40 ka to 50 ka BP. The lowermost interstadial sediments may be some 50 ka to 70 ka old. In addition, the deposition of these marine sediments up to 50 m above present sea level may indicate a preceding glaciation note recorded by deposits at the site.

E. Larsen, Geologica/ Survey of Norway, PO Box 3006 Lade, N-7002 Trondheim, Norway.
B. Ward, Department of Geology,University of Alberta, Edmonton, Alberta T6G 2E3, Canada.

029-196X
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