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Paleomagnetic results from Early Eocene intrusions, north‐central Montana: Implications for North American apparent polar‐wandering
Author(s) -
Diehl J. F.,
BeskeDiehl S.,
Beck M. E.,
Hearn B. C.
Publication year - 1980
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/gl007i007p00541
Subject(s) - paleomagnetism , geology , geomagnetic pole , cretaceous , apparent polar wander , polar wander , earth's magnetic field , paleontology , ecological succession , north pole , igneous rock , polar , magnetostratigraphy , paleogene , physical geography , geography , ecology , physics , quantum mechanics , astronomy , magnetic field , biology
Paleomagnetic poles have been determined from two Early Eocene igneous centers located in the north‐central Montana alkalic province. The mean paleomagnetic pole for the Highwood Mountains lies at 81.2°N, 167.3°E (N = 29; α 95 = 7.1; k = 15.4) while the corresponding pole for the Bearpaw Mountains is located at 80.5°N, 198.4°E (N = 18; α 95 = 5.8; k = 37.0). Combining these results with studies on Eocene rocks from Wyoming, gives a reference pole located at 81.7°N, 171.2°E with a circle of 95% confidence of 4.4°. This data, when compared to other early Tertiary results, the Cretaceous stillstand poles and the well grouped mid‐Tertiary poles from the continental interior, suggest that for the period 120 to 15 m.y.B.P. apparent polar‐wandering for North America occurred as a succession of rapid shifts of the geomagnetic pole separated by periods of stillstand.