Crustal evolution of Fennoscandia—palaeomagnetic constraints

摘要: Abstract Palaeomagnetic poles from Fennoscandia, ranging in age Archaean to Tertiary, are compiled and graded using a modified Briden-Duff classification scale. An new “filtering” technique is applied select only the most reliable for analysis. The filtering takes into account following information: 1. (1) source block of rock unit, 2. (2) rock, 3. (3) magnetization component, 4. (4) scatter palaeomagnetic directions, 5. (5) information multicomponent analysis natural remanent (NRM), 6. (6) whether pole considered belongs cluster or subcluster poles, 7. (7) magnetic polarity 8. (8) author's original assignment results. Data still insufficient drawing separate Apparent Polar Wander Paths (APWP) different blocks cratons Fennoscandia. Treating Fennoscandia as single plate, APWP Permian constructed. From five previously drawn loops (or “hairpins”), one, Jatulian loop (2200-2000 Ma), disappears filtering. during 1925-1700 Ma 1100-800 ago linked Svecofennian Sveconorwegian orogenies, respectively. data support concept that these orogenies took place episodically; three distinct orogenic pulses (early, middle late) can be distinguished plots palaeopoles. drift history presented. During geological history, has occupied low moderate latitudes undergone considerable latitudinal shifts rotations. have kinematic characteristics. orogeny, drifted slowly while rotating large amount an anticlockwise sense. it rapidly rotated first clockwise then anticlockwise. striking feature velocity curves is, however, pronounced maxima rotation rates (~ 9 cm/yr ~ 0.8°/Ma, respectively) late Subjotnian-Jotnian anorogenic magmatism rifting phase (~1450-1250 ago), possibly reflecting passage across thermal upwelling (hotspot) at equatorial latitudes. use palaeomagnetism delineating dating movements between demonstrated with examples POLAR Profile area, northernmost section European Geotraverse.