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Fine tuning the radiometrically derived geomagnetic polarity time scale (GPTS) for 0–10 Ma
Author(s) -
Baksi Ajoy K.
Publication year - 1995
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 - 10.1029/94gl03214
Subject(s) - earth's magnetic field , geology , polarity (international relations) , geomagnetic reversal , scale (ratio) , geodesy , geophysics , magnetic field , physics , geography , chemistry , cartography , biochemistry , quantum mechanics , cell
New 40 Ar/ 39 Ar step‐heating ages for geomagnetic field reversals at 3.2 and 4.5 Ma, along with previous data at ∼1, 2, 10 and 16 Ma, are used to derive a geomagnetic polarity time scale for 0–10 Ma. These ages for chron boundaries are fitted to the relative widths of the polarity intervals on the ocean floor, using a cubic spline technique. The interpolated ages of chrons for 0–6 Ma are in good agreement with the astronomical time scale and differ considerably from earlier attempts, based, in part, on K‐Ar dates. Significant differences between the interpolated ages and the astronomical time scale are noted for the onset of the Olduvai and Reunion (sub)chrons; there is better agreement if 40 Ar/ 39 Ar data obtained from direct dating of these chrons is utilized. This time scale is estimated to be accurate to ±1% for 0–6 Ma; for 6–10 Ma, the lack of a tie‐point limits the accuracy to about ±2%.