The Halland Coastal Moraines: Are they end moraines or glaciotectonic ridges?

The “Halland Coastal Moraines” refer to the numerous NW—SE trending ice-transverse ridges in the Varberg—Falkenberg area along the west coast of Sweden. Previously all of the ridges have been interpreted as end moraines, formed during the Late Weichselian deglaciation, circa. 13,000 to 13,500 14C years B.P. ( Fig. 1 ). Stratigraphical studies have revealed that not all of the ridges are end moraines. Some are glaciotectonic ridges formed by a readvance of the ice after 12,600 14C years B.P. ( Fig. 10 ). This readvance along the west coast followed an icefree period of at least 500 years. The readvance is suggested to have originated east of the Gőteborg End Moraine and have extended west of the Tofta Ridge and probably severals km off the present Swedish west coast. The ridges associated with drumlins are inferred to have formed during this readvance ( Fig. 1 ). In such case the lateral extent of the readvance must at least have been from Falkenberg to Onsala. The advancing glacier was possibly a warm based ice stream or surge which protruded out from the main ice sheet.