The Early Carboniferous Mageroy dykes, northern Norway: palaeomagnetism and palaeogeography
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Palaeomagnetic data from the 337 Ma Mageroy dykes (northern Norway) are of exceptionally high quality, and a positive contact test along with an existing regional result from the Silurian Honningsvag Igneous Suite attests to a primary Early Carboniferous magnetic signature. The palaeomagnetic pole (S 14.8degrees, E320.1degrees, dp/dm = 4.4/8.6degrees) is the first Early Carboniferous pole from Baltica, and implies that northernmost Norway-Greenland, the Barents Sea and Svalbard were located at tropical to low northerly latitudes at this time. Northward drift during Carboniferous times (5-6 cm/yr) as demonstrated from palaeomagnetic data is also reflected in the sedimentary facies in the Barents Sea realm, that is, a change from tropical (Early Carboniferous) to subtropical (20-30degrees N) carbonates and evaporites in the Late Carboniferous. The Mageroy dykes are continental tholeiites which intruded into a set of NW-SE-trending normal faults parallel to the Trollfjorden-Komagelva Fault Zone and the Mageroysundet Fault immediately to the north and south of Mageroya, respectively. These, and many other NW-SE-trending faults (onshore and offshore), were active during Late Palaeozoic extension, and the dykes were probably contemporaneous with the earliest syn-rift sedimentation in the Barents Sea (for example, the Nordkapp Basin).