Early Weichselian interstadial (MIS 5c) summer temperatures were higher than today in northern Fennoscandia |
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Authors: | Minna Väliranta Hilary H Birks Karin Helmens Stefan Engels Mikko Piirainen |
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Institution: | 1. Department of Vegetation Ecology, Institute of Botany, Academy of Sciences of the Czech Republic, Lidická 25/27, CZ-602 00 Brno, Czech Republic;2. Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlá?ská 2, CZ-61137 Brno, Czech Republic;1. State Key Laboratory for Geomechanics and Deep Underground Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China;2. School of Mechanics and Civil Engineering, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China |
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Abstract: | Only fragmentary biostratigraphical interstadial data exist from northern European high latitudes. The palaeoenvironmental interpretations for the early part of the Last Glaciation in northern Fennoscandia are mainly based on palynological evidence that suggests open birch woodland and a sub-arctic climate. Plant macrofossils from the Sokli sediment sequence in Finnish Lapland provide different evidence of interstadial climate conditions. The assemblage includes several species that currently have considerably more southern distribution ranges. This indicates that ca 100,000 years ago summer temperatures were warmer than today. The mean minimum July temperature may have been as high as 16 °C and the effective temperature sum may have been 1000 in day-degree units (d.d.), the modern values being 13 °C and 650 d.d., respectively. The contemporary astronomical forcing mechanisms may have resulted in a weaker north–south temperature gradient and a longer growing period, creating more favourable climate conditions compared with today. |
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