Neoglacial activity in Finland: dating the evidence from glaciolacustrine sediment sequences in the Halti-Ridnitšohkka region

Palaeomagnetic dating of sediment sequences from lakes Pihtsusjärvi and Haltijärvi in Enontekiö, northwestern Finnish Lapland, provided a chronology for a study of the palaeohydrological and glacier history of the Halti-Ridnitšohkka fells area. Both sequences exhibited a stable primary component of the NRM direction, allowing a comparison of the secular variation records with the chronology of Lake Nautajärvi reference curves (NRM) to provide a chronological framework for the present study. The basins of Lakes Pihtsusjärvi and Haltijärvi were formed 10 500 and 5500 cal. BP, respectively. Minerogenic layers found from studied Lake Pihtsusjärvi sequences provided evidence of postglacial activity of the Halti fell valley glacier. The results indicated that the Halti glacier was active soon after the continental ice sheet had retreated from the area at around 10 000 9000 cal. BP, during which time the Kovdajohka valley terminal and recessional moraines were formed. This was followed by a Holocene thermal maximum (HTM) in northern Fennoscandia, which was interrupted by climate cooling at around 6000 cal. BP. The basal age of the Lake Haltijärvi sediment core and Lake Pihtsusjärvi sediment stratigraphy indicated minor, short-term neoglacial activity in the Halti fell vicinity between c. 6000 and 5500 cal. BP.