Calendar year age estimates of Allerød–Younger Dryas sea‐level oscillations at Os, western Norway

Abstract

Abstract:A detailed shoreline displacement curve documents the Younger Dryas transgression in western Norway. The relative sea-level rise was more than 9m in an area which subsequently experienced an emergence of almost 60 m. The sea-level curve is based on the stratigraphy of six isolation basins with bedrock thresholds. Effort has been made to establish an accurate chronology using a calendar year time-scale by 14C wiggle matching and the use of time synchronic markers (the Vedde Ash Bed and the postglacial rise in Betula (birch) pollen). The sea-level curve demonstrates that the Younger Dryas transgression started close to the Allerød-Younger Dryas transition and that the high stand was reached only 200 yr before the Younger Dryas-Holocene boundary. The sea level remained at the high stand for about 300 yr and 100 yr into Holocene it started to fall rapidly. The peak of the Younger Dryas transgression occurred simultaneously with the maximum extent of the ice-sheet readvance in the area. Our results support earlier geophysical modelling concluding a causal relationship between the Younger Dryas glacier advance and Younger Dryas transgression in western Norway. We argue that the sea-level curve indicates that the Younger Dryas glacial advance started in the late Allerød or close to the Allerød-Younger Dryas transition.

Neotectonic faulting and the Late Weichselian shoreline gradients in SW Norway

“…South of Bergen, a good fit is obtained using a slightly curved line or a straight line with a constant gradient of ca.1.25 m/km (see also Lohne et al, in press). However, since Grindavoll, which is an isolation basin that precisely records the YD maximum highstand sea level (Lohne et al, 2004), sits as an outlier below the lines, this suggests that the highstand levels are not adequately represented by a single, straight or curved line. The shore levels along the first ca.…”

“…However, again Grindavoll sits as an outlier below the line. Since this isolation basin precisely records the YD maximum highstand sea level (Lohne et al, 2004), this indicates that the highstand levels along the transect are not adequately represented by a single, curved or straight line. The data from Grindavoll are satisfied if a hinge point in the YD maximum highstand shoreline is introduced between Ulven (no.…”

“…32 and 65) suggest that these ridges, which are attributed to the maximum highstand, were formed very late in the YD. The Betula rise, which is a pollen stratigraphic event dated close to the YD-Holocene boundary (e.g., Paus, 1988;Lohne et al, 2004), is found to immediately postdate the YD maximum highstand (see nos. 3, 7, 38, 50, 55).…”

“…e Braaten and Hermansen (1985). f A regionally-recorded pollen stratigraphical event dated to close to the YD-Holocene boundary (see e.g., Paus, 1988;Lohne et al, 2004). g Mangerud et al (1984).…”

Middle Pleistocene to Holocene geochronology of the River Aguas terrace sequence (Iberian Peninsula): Fluvial response to Mediterranean environmental change

“…However, the river incision of 6 m during the Younger Dryas corresponds to a minor sealevel fall. Dias et al (2000) postulate a Younger Dryas regression of 20 m for the Portuguese shelf, whereas Lohne et al (2004) determined a sea-level fall of 9 m at the western Norwegian Atlantic coast.…”