Preboreal deglaciation chronology and marine limits of the Lyngen‐Storfjord area, Troms, North Norway

Abstract

Scattered marginal moraines in the Lyngen‐Storfjord area proximally to the Tromsø‐Lyngen moraine were formed by the Scandinavian ice‐sheet during its retreat in the Preboreal. They correspond to ice‐front positions in the main fjords and fjord‐valleys where between three and four major and, in places, some minor ice‐front accumulations occur. These have been correlated using the marine limits related to synchronous shorelines. Dates for the shorelines and moraines have been derived from a shoreline emergence curve based on 14 C dated shore levels from North Norway. Two major, and probably at least one minor, climatically induced, glacial events are indicated: the Ørnes event c. 9800–9900±150 B.P., the Skibotn event 95–9600±150 B. P., and a younger event c. 9400±250 B. P. The inner fjord‐valleys were probably deglaciated by c. 9100 B. P. Final deglaciation of the innerplateau during late Preboreal or early Boreal was characterized by downwasting.