Paleomagnetic results from the Upper Triassic of East Greenland

Publisher: John Wiley & Sons Inc

E-ISSN: 2156-2202|79|23|3302-3307

ISSN: 0148-0227

Source: Journal Of Geophysical Research, Vol.79, Iss.23, 1974-08, pp. : 3302-3307

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Abstract

Study of a 12.2‐m inclined core from within the Malmros klint member of the Fleming Fjord formation at 71.73°N, 23.42°W reveals a N‐R‐N‐R‐N polarity sequence within the core, where N is normal and R is reversed. The lower two normal zones are each less than 1 m thick and are separated by the 1‐m‐thick lower reversed zone. The upper transition (R to N) is abrupt. A paleomagnetic pole position at 103°E, 34°N has been calculated from selected reversed samples. This pole is considered well determined in that (1) it is almost exactly 180° opposite a pole calculated from normal polarity samples and (2) samples involved in the determination appear to be well demagnetized when they are plotted on orthogonal vector demagnetization plots. It does not agree, however, with the position calculated by rotating the mean North American Upper Triassic paleomagnetic pole about the Greenland‐North American rotation axis by an amount sufficient to open the Davis Strait in post‐Triassic time. The calculated pole position is approximately 20° ESE of a similar pole predicted from European data, although severe selection of the data would tend to halve the distance to the predicted European pole. The paleomagnetic pole derived from the Fleming Fjord formation in this study supports the suggestion that Greenland was attached to the European plate rather than to the North American plate in the Late Triassic and was located considerably south of its present location at that time.