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Late Paleozoic remagnetization of the Trenton Limestone
Author(s) -
McCabe Chad,
Van der Voo Rob,
Ballard Martha M.
Publication year - 1984
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl011i010p00979
Subject(s) - paleozoic , geology , paleomagnetism , natural remanent magnetization , remanence , ordovician , permian , rock magnetism , paleontology , diagenesis , demagnetizing field , magnetite , polar wander , magnetic mineralogy , magnetization , geochemistry , magnetic field , physics , quantum mechanics , structural basin
Samples of the Middle Ordovician Trenton Limestone were collected from 8 sites in Quebec, Ontario, and New York State for paleomagnetic study. Stepwise thermal demagnetization reveals a very well defined characteristic magnetization that has a corresponding paleomagnetic pole at 53.0° N, 126.9° E (K=97.7, A‐95=2.7°). This pole is not at all close to other Ordovician poles from cratonic North America but is near Late Carboniferous and Early Permian ones, indicating that the Trenton was remagnetized in the Late Paleozoic. An earlier paleomagnetic investigation of the Trenton gave a pole that did not appear to be Late Paleozoic in age. However, we demonstrate that this earlier study failed to isolate the ancient characteristic magnetization. Rock magnetic experiments and analyses of magnetic extracts show that the carrier of magnetization is Fe 3 O 4 that does not contain Ti or other elements in solid solution that would indicate a detrital source. The magnetite and its associated remanence appear to have a diagenetic origin.