A palaeomagnetic survey of the Jotnian dolerites of central--east Sweden

• Published in: Geophysical Journal International
• Main Author: Piper, J. D. A.
• Format: Text
• Language: English
• Published: Oxford University Press 1979
• Subjects: Research note; Greenland
• Online Access: http://gji.oxfordjournals.org/cgi/content/short/56/3/461; https://doi.org/10.1111/j.1365-246X.1979.tb00178.x

The Jotnian igneous episode of central—east Sweden is represented by dolerite sills distributed over an area of 5000 km2. After detailed af and thermal cleaning of 265 samples from 46 sites in these dolerites, 43 of the sites yield a mean direction of magnetization D = 47.8°, I =-45.5° (α 95 = 2.6°) and a palaeomagnetic pole at 156.5° E, 7.5° S. The results are combined with other data from the same region to derive an overall mean palaeomagnetic pole for the Jotnian igneous episode. All samples have the same polarity and directions of magnetization agree closely with dolerites attributed to the Jotnian episode from elsewhere in the Baltic Shield. The Jotnian igneous intrusions of Sweden are dated 1247-1213 Ma and are broadly contemporaneous with the Mackenzie magmatic episode in North America (1205-1189 Ma) and dyke intrusions within the Gardar Province of South Greenland (1250-1212 Ma). These igneous events all have the same polarity on the continental reconstruction derived from 2000-1200 Ma palaeomagnetic data with the Laurentian and Baltic Shields in juxtaposition.