Dating early Holocene palaeoseismic event(s) in the Gulf of Bothnia, Baltic Sea |
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| Authors: | KAISA-LEENA HUTRI ATKO HEINSALU AARNO T KOTILAINEN ANTTI E K OJALA |
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| Institution: | Kaisa-Leena Hutri (e-mail: ), STUK, Radiation and Nuclear Safety Authority in Finland, Nuclear Waste Management, P.O. Box 14, FIN-00881 Helsinki, Finland;Atko Heinsalu, Institute of Geology, Tallinn University of Technology, Estonia pst. 7, ES-10143 Tallinn, Estonia;Aarno T Kotilainen, Geological Survey of Finland, P.O. Box 96, FIN-02150 Espoo, Finland;Antti E. K. Ojala, Geological Survey of Finland, P.O. Box 96, FIN-02150 Espoo, Finland |
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| Abstract: | Hutri, K.-L., Heinsalu, A., Kotilainen, A. T. & Ojala, A. E. K. 2007 (January): Dating early Holocene palaeoseismic event(s) in the Gulf of Bothnia, Baltic Sea. Boreas , Vol. 36, pp. 56–64. Oslo. ISSN 0030–9483.
Deformation structures in submarine Holocene sediments caused by palaeoseismicity have recently been found in the Olkiluoto area, Gulf of Bothnia, Baltic Sea, within old fracture zones of bedrock. In this study, the palaeoseismic event(s) was dated and the palaeoenvironment was characterized using palaeomagnetic, biostratigraphical and lithostratigraphical methods, thereby enhancing the reliability of the chronology. The variations in the inclination and declination of the Olkiluoto sediment core showed very good correlation with the palaeosecular variations recorded in the annually laminated long lake sediment record from Lake Nautajarvi in central Finland. Combined litho-, bio- and palaeomagnetic stratigraphy revealed an age estimation of 10 650 to 10 200 cal. yr BP for the palaeoseismic event(s), which coincides with postglacial bedrock faulting in northern Fennoscandia. |
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