Abstract

Thermal demagnetization of red bed samples from the Cumberland Group (Pennsylvanian) of Nova Scotia indicates that the fossil magnetization is composed mainly of a thermally distributed (up to 650 °C) magnetization. The direction changes between heatings are small, indicating that this magnetization was acquired in a field of constant polarity. A fold test (10 sites) shows that the magnetization predates the folding, which according to geological evidence occurred shortly after deposition. The results (direction 172°, + 16°; k = 85; pole 36 °N, 125° E) are compared with other results obtained from Paleozoic formations. Comparison between continents indicate that a 30° apparent polar change during the Paleozoic is probable. From the Dominion Observatory results, it is suggested that at least half of the change took place during late Paleozoic times and probably during the Pennsylvanian Period.

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