Naakenavaara Interglacial - a till-covered peat deposit in western Finnish Lapland

Abstract

More than 100 till-covered organic deposits are currently known in the Finnish Lapland. All others, except Naakenavaara, are interpreted as having deposited during either the Early-Weichselian Peräpohjola/Maaselkä interstadial or the Eemian interglacial stage. At Naakenavaara, Kittilä, a 0.5–1.5 m peat deposit under till bed IV, was submitted to pollen and macrofossil studies. Pollen analysis of the Naakenavaara peat deposit indicates a flora dominated by conifers: Pinns, Picea, possibly Picea Sect, omorica and, in the upper part of the deposit, Larix. Bruckenthalia type pollen and spores of Osmunda also occur. The pollen flora reflects the temperate climatic conditions of an interglacial stage. Macrofossil analysis revealed four exotic taxa not found in Finland's present natural flora: Aracites interglacialis, Larix sp., Abies sp., and Picea omorica. The site was a wet mire with a sparse growth of Pinus silvestris and Larix sp., where the climate was more temperate than it is today. The main peat-forming plant was the extinct herb species Aracites interglacialis, whose inferred age is Holsteinian interglacial. From the stratigraphic position and macrofossil content of the peat deposit, the Naakenavaara interglacial has been correlated with the Holsteinian interglacial, although it might be even older.

Keywords

• peat
• till
• stratigraphy
• pollen diagrams
• macrofossils
• Aracites interglacialis
• interglacial environment
• Pleistocene Holsteinian
• Naakenavaara
• Kittilä
• Finland