Paper No. 7
Presentation Time: 10:30 AM
PALEOMAGNETIC STUDIES OF THE MESOPROTEROZOIC UNITS IN SW FINLAND WITH IMPLICATIONS FOR A NORTHERN EUROPE – NORTH AMERICA (NENA) CONNECTION WITHIN NUNA SUPERCONTINENT
SALMINEN, Johanna1, MERTANEN, Satu
2, EVANS, David A.D.
3 and KLEIN, Robert
1, (1)Physical Sciences, Division of Geophysics, University of Helsinki, PO Box 64, 00014 University of Helsinki, Helsinki, 00014, Finland, (2)Geological Survey of Finland, P.O. Box 96, Espoo, FI-02151, Finland, (3)Department of Geology and Geophysics, Yale University, New Haven CT 06520-8109, USA, New Haven, CT 06520, johanna.m.salminen@helsinki.fi
Paleoproterozoic supercontinent Nuna (Columbia, Hudsonland) has been proposed by several authors [e.g. 1, 2, 3]. Many recent reconstructions of this supercontinent support, within the analytical uncertainties, that the core of Nuna was formed by a single NENA (Northern Europe – North America) juxtaposition between Baltica and Laurentia between ca. 1.75 Ga and ca. 1.27 Ga [4, 5, 6]. However, recent paleomagnetic data from ca. 1.63 Ga Melville Bugt dykes in Greenland does not support that fit [7]. To address these concerns, we present new paleomagnetic data from Late Mesoproterozoic diabase dyke swarms (Satakunta: 1565 Ma and Åland: 1577-1540 Ma) and from Mesoproterozoic Satakunta sandstone located in SW Finland. A dual-polarity, high-stability remanence component from the dated 1565 Ma Satakunta dyke swarm with the paleopole of Plat=29.3°N, Plon=188.1°E (A95 = 6.6°), is confirmed to be primary by positive baked-contact tests, and suggests that NENA was valid also at 1.63-1.54 Ga [8, 9]. Comparable paleopole (Plat=26.8°N, Plon=173.5°E; A95 = 5.7°) from the ca. 1.6 Ga Satakunta sandstone gives support to this result.
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