Har Jæren vært dekket av en Skagerak-bre? Er "Skagerak-morenen" en marin leire?

Abstract

Jæren is a low plain on the coast of southwestern Norway. This plain is covered with relatively thick Quaternary deposits including a very bouldary W\u00CFrm till on top of calcareous clays and stratified sand and gravel. In some areas the calcareous clay contains stones from the Baltic and the Oslofjord regions, and crushed shells. The shells has therefore previously been interpreted as a till deposited by a Skagerak-glacier which moved westwards from the Oslofjord and the Baltic regions during the Riss Glaciation. Information obtained during reconnaisance investigations and through a thorough study of the literature suggests that \"the Skagerak till\" is more likely a marine (glacio-marine) clay deposited during the late part of the Riss Glaciation (or the G\u00CEttweiger Interstadial) when sea level at Jæren was at least 200 m higher than today. The stones in the clay were most likely ice rafted, and the shells were crushed by the overriding W\u00CFrm ice sheet which also included marine clay in its till.