Geophysical Journal | 2007 volume 29 6

Jurassic paleomagnetic Pole of the Greyama Land (Antarctic Peninsula)

© M.I. Orlova

According to the results of the studies it has been found that in exposures of rocks of Upper Jurassic volcanic group as well as in Pre-Andian dykes of microdiorites from the islands of the Argentinian archipelago and nearby cost of the Antarctic Peninsula stabile component of the primary natural remanent magnetization prevails, which appeared before the beginning of tectonic movements. Within the limits of each of the studied areas different bedding of rocks is connected different direction of shifting. According to the results of t and h-demagnetization average directions of N and R components of the characteristic component have been calculated In the ancient coordinate system are transformed into direct polarity D/I=80/-59; n=21; α95=5,4; K=35,7. Good agreement of paleomagnetic directions reduced to direct polarity has been shown in the rocks of the Oscar series from the northern part of the Antarctic Peninsula (the Greyama Land) in four exposures remote from each other at big distances. By superposition of new Middle Jurassic Pole from the Greyama Land with standard one for Eastern Antarctica the block of the Antarctic Peninsula is replaced to the initial position by clockwork by rotation of about 13°. In such a case of reconstruction the Antarctic Peninsula should rotate counter clockwork as to the block of Eastern Antarctica.

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