PALAEOMAGNETISM OF THE SVECOFENNIAN LOFTAHAMMAR GABBRO AND SOME JOTNIAN DOLERITES IN THE SWEDISH PART OF THE BALTIC SHIELD

Abstract

Poorter, R.P.E., 1976. Palaeomagnetism of the Svecofennian Loftahammar gabbro and someJotnian dolerites in the Swedish part ofthe Baltic Shield. Phys. Earth Planet. Inter., 12: 51—64. The Svecofennian Loftahammar gabbro (Rb—Sr isochron age 1,694 - 106 year) and Jotnian dolerites (K—Ar isochron age 1,245 106 year) in Sweden were found to have palaeomagnetic pole positions in close agreement with poles from other Svecofennian rocks in Sweden and Jotnian dolerites in Finland, respectively. These results support Neuvonen’s apparent polar wandering path during the period from 1,900 lO~to 1,300 106 year. A reconstruction of the position of the Baltic Shield during the (1,900—1,200) 10 6-year interval, based on available pole positions, indicates that the Baltic shield was close to Greenland and the North American Shield and reveals a contiguity of North Atlantic geologic-geochronological zones until 1,200 106 year ago.