A palaeomagnetic and 40Ar/39Ar study of mafic dykes in southern Sweden: A new Early Neoproterozoic key-pole for the Baltic Shield and implications for Sveconorwegian and Grenville loops
MetadataShow full item record
We present the results of palaeomagnetic and40Ar/39Ar studies of the Proterozoic mafic dykes in the Norrköping and Falun areas of the southern Sweden. The primary remanence of two 939 ± 3 Ma dykes is supported by the rigorous baked contact test. The remanence direction of two other dykes, one of which was previously U–Pb dated at 946 ± 1 Ma is close to the reverse direction of 939 Ma dykes. Using these results together with previously published 935 ± 5 Ma palaeomagnetic data from the Göteborg-Slussen mafic dykes and some dykes from the Falun area we calculated the mean 946–935 Ma palaeopole for Baltica (0.9° S, 240.7° E, A95= 6.7), which can be qualified as the key pole. Using this pole together with other date we conclude that the Grenville and Sveconorwegian loops of Laurentian and Baltican Apparent Polar Wander Paths are temporary displaced by 100–150 m.y. We propose new palaeogeographic reconstructions of Baltica and Laurentia at ca. 940 Ma and ca. 850 Ma. We also present two new Mesoproterozoic non-key poles from 1410 Ma and 1595 Ma dykes.
Showing items related by title, author, creator and subject.
Palaeomagnetism and geochronology of mid-neoproterozoic yanbian dykes, South China: Implications for a c. 820-800 Ma true polar wander event and the reconstruction of RodiniaNiu, J.; Li, Zheng-Xiang; Zhu, W. (2016)We present new palaeomagnetic data from two generations of mafic dykes in the Yanbian region of the western South China Block, dated by the zircon U-Pb method at 824±6 and 806±8 Ma, respectively. The primary origin for ...
Fennoscandia before Nuna/Columbia: Paleomagnetism of 1.98–1.96 Ga mafic rocks of the Karelian craton and paleogeographic implicationsLubnina, N.; Pisarevskiy, Sergei; Stepanova, A.; Bogdanova, S.; Sokolov, S. (2017)Numerous mafic dykes, sills and intrusions with ages between 1985 Ma and 1960 Ma are exposed near the Onega Lake in southern Karelia, Russia. The paleomagnetic analysis of these rocks has revealed a stable remanence with ...
Palaeomagnetism of palaeozoic glacial sediments of northern ethiopia: A contribution towards african permian palaeogeographyKidane, T.; Bachtadse, V.; Alene, M.; Kirscher, Uwe (2013)One hundred fourteen oriented palaeomagnetic core samples were collected from 13 palaeomagnetic sites on subhorizontal to tilted glacial sediments at five localities of Northern Ethiopia. Combined alternating field (AF) ...