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Neoproterozoic palaeomagnetic directions in rocks from a key section of the Protogine Zone, southern Sweden

1998; Oxford University Press; Volume: 133; Issue: 1 Linguagem: Inglês

10.1046/j.1365-246x.1998.1331497.x

1365-246X

Sergei S. Pisarevsky, Géran G. Bylund,

Geology and Paleoclimatology Research

New palaeomagnetic data from the Protogine Zone (PZ) of southern Sweden are presented together with data from east and west of the zone. They confirm previous palaeomagnetic results from the PZ that indicate a difference in magnetic properties between rocks north and south of a section at 57°N, here called the Alvesta—Ljungby Palaeomagnetic Borderzone (ALPB). The results are divided into four groups: group I [declination (D)=297°, inclination (I)=−78.5°, α95=2.4°, pole position 42.7°S, 220.9°E]; group II (D=129.4°, I=52.2°, α95=4.2°, pole position 9.4°S, 235.5°E); group III (D=155.4°, I=61.3°, α95=4.9°, pole position 11.6°S, 211.2°E); group IV (D=125.5°, I=35.4°, α95=5.4°, pole position 0.8°N, 244.1°E). A fifth, poorly defined, group has a mean direction D=304.5°, I=5.4°, α95=15.1° and pole position 21.3°N, 255.9°E. These palaeopoles fall on the c. 1050–900 Ma Sveconorwegian Loop of the Fennoscandian apparent polar wander path. Together with previously published data from southern Norway, the group I poles define the high-latitude apex of the loop at c. 950–930 Ma. The groups II—V palaeopoles are situated at low latitudes but it is difficult to place them in chronological order owing to a lack of age data and two possible interpretations, that is of an open or a closed loop.