Rock magnetic evidence for inclination shallowing in the early Carboniferous Deer Lake Group red beds of western Newfoundland
A paleomagnetic and rock magnetic study of the Carboniferous Deer Lake Group red beds of Newfoundland was performed to detect and correct for inclination shallowing. Results indicate a primary remanence carried by magnetite, with a mean direction of D = 179.7°, I = 33.7°, α 95 = 7.2° which correspon...
| Published in: | Geophysical Journal International |
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| Main Authors: | , |
| Format: | Text |
| Language: | English |
| Published: |
Oxford University Press
2010
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| Subjects: | |
| Online Access: | http://gji.oxfordjournals.org/cgi/content/short/181/1/275 https://doi.org/10.1111/j.1365-246X.2010.04537.x |
| Summary: | A paleomagnetic and rock magnetic study of the Carboniferous Deer Lake Group red beds of Newfoundland was performed to detect and correct for inclination shallowing. Results indicate a primary remanence carried by magnetite, with a mean direction of D = 179.7°, I = 33.7°, α 95 = 7.2° which corresponds to a paleopole position of 22.2°N, 122.3°E, A 95 = 7.6°. Correcting the inclination using anisotropy of anhysteretic remanence and the measured individual particle anisotropy gives a corrected direction of D = 178.8°, I = 50.9°, α 95 = 6.3° corresponding to a paleopole position at 8.4°N, 122.7°E, A 95 = 7.2°. This correction is larger than that of other red beds from the Maritime Provinces of Canada, but is consistent with paleoenvironmental reconstructions, placing North America in a more arid climate zone. Our inclination-corrected results have important implications for this portion of North America's apparent polar wander path and suggest a correction is needed for other red bed-derived APWPs. We have determined the range of flattening factors f , defined as the proportionality constant between the tangents of the measured ( I m ) and field ( I o ) inclinations, tan( I m ) = f tan( I 0 ), from this study and previous inclination correction studies to estimate inclination corrections. Using the range of haematite f factors observed in this study to correct the Neogene red bed inclinations from the Vallès-Penedès Basin (NE Spain) yields inclinations consistent with the known geomagnetic field inclination in the Neogene, thus indicating that the range of f factors reported here may be used to estimate the magnitude of inclination shallowing in red beds. |
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