The timing of deglaciation and sequence of pioneer vegetation at Ringsaker, eastern Norway – and an earthquake-triggered landslide

Jan Mangerud,Ole Nashoug,Rolf Sørensen,Lene S Halvorsen,John Inge Svendsen,Anna L.C Hughes,Hilary H Birks,Johan Petter Nystuen,Aage Paus

doi:10.17850/njg98-3-03

Abstract

The timing of deglaciation and sequence of pioneer vegetation at Ringsaker, eastern Norway – and an earthquake-triggered landslide

Highlights

The age of the deglaciation of the last Scandinavian Ice Sheet in the interior of Norway is poorly constrained (Hughes et al, 2016)
After looking at the exposed strata in the ditches and considering the surrounding terrain, we proposed two alternative hypotheses; first, that the peat is of Holocene age and overlying strata are landslide deposits, and second, that the peat is of interglacial age and the overlying strata are glacial deposits
The lower diamicton is succeeded by thin silt and sand beds that we collectively label the silt-sand member and interpret as lacustrine sediments

Summary

Introduction

The age of the deglaciation of the last Scandinavian Ice Sheet in the interior of Norway is poorly constrained (Hughes et al, 2016). For the entire area from the southern end of Lake Mjøsa (Fig. 1) to the location of the ice divide, a stretch of some 200 km, only a single radiocarbon age related to the deglaciation is published, and this date, from Saug (Fig. 1), has a large uncertainty; 10,247–10,646 cal years BP (68.3% confidence interval; Sørensen, 1982). A series of ice-front deposits are mapped, from the Ra Moraine dated to the Younger Dryas and crossing Oslofjorden between Moss and Horten, to Minnesund at the southern end of Lake Mjøsa (Fig. 1). The northernmost of these that is radiocarbon-dated is the Hauerseter. We present plant macrofossil data representing the pioneer vegetation at Hemma

Methods

Results and discussion

Hemma-46-4 Poz-93349

HippophaëArtemisiaPoaceae

Conclusions