THE JAEREN AREA, A BORDER ZONE OF THE NORWEGIAN CHANNEL ICE STREAM

The coastal lowlands of Jaeren, southwestern Norway, have an extensive cover of Quaternary sediments. Lithological, biostratigraphical and g eochronological investigations of a series of boreholes across Jaeren have allowed us to combine earlier and new information on these deposi ts into a temporal model of Quaternary sedimentation. The cores show e vidence of at least four ice free episodes with marine deposition, dur ing mainly arctic conditions. The oldest of these is considered to be ca. 200 ka old and the youngest one is the Sandnes interstadial which is C-14 AMS dated to 32 ka BP. Interbedded between these units are 10- 40 m thick units of till with components of marine material. These fin dings, together with a re-evaluation of distinct morphological feature s on Jaeren, as well as earlier provenance studies, strongly suggest t hat Jaeren has been a boundary zone between an ice stream following th e Norwegian Channel draining a substantial part of the southern region of the Fennoscandian ice sheet, and local ice from south-western Norw ay. Through multiple periods of glaciation starting ca. 1.1 myr (milli on years) ago, the Norwegian Channel ice stream has been the main cond uit of erosion products from southern Scandinavia to the deep Norwegia n Sea. Comparison with ice stream profiles from Antarctica suggests th at the deposition of relatively young marine sediments as high as ca. 200 m a.s.l. on Jaeren is a result of glacial isostasy, rather than re gional tectonic movements. (C) 1998 Elsevier Science Ltd. All rights r eserved.