International Geologiical Congress - Oslo 2008


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HPS-05 Recent developments in the Geologic Timescale


Magnetic stratigraphy of the early paleocene, Maastrichtian and Campanian in western Canada: Chrons, subchrons and tiny wiggles


John Lerbekmo, University of Alberta (Canada)


Magnetostratigraphic analysis of 15 outcrop sections and 6 long cores in Alberta and Saskatchewan embrace magnetozones 27n through 33r. Sampling at time-stratigraphic intervals of 10 to 30 kyr has led to the identification of some 70 magnetosubzones in 27n, 27r, 28r, 29n, 29r, 31n, 31r, 32n, 32r, 33n, and 33r. The durations of opposite polarity subchrons are relatively short compared to the time spans of the chrons; the shortest ones lasted typically ca. 40 kyr, but a few appear to have been even shorter. The correlations between the subchrons and their representations as 'tiny wiggles' in seafloor magnetic profiles will be illustrated. Most, but not all, 'tiny wiggles' reflect polarity change. It appears that there is a genetic difference between 'tiny' and 'very tiny' wiggles, only the latter representing intensity variations of the geomagnetic field.


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