Magnetostratigraphy

Magnetostratigraphic studies in the Pit were undertaken by V. A. Schmidt, University of Pittsburgh Paleomagnetics Laboratory, just prior to his untimely death. Samples from levels

14-8 recorded predominantly reversed polarities, although there is an admixture of intermediate and to a much lesser extent normal components as well. The data suggested to Schmidt (pers. comm., 1993) that levels 14-8 are older than 780 Ka, which marks the Brunhes-Matuyama boundary. They would fall in Chron 1r of Berggren et al. (1995). Samples from the base of level 5 provided equivocal magnetic signatures. Bell and Barnosky (2000) suggested that the presence of predominantly reversed samples with intermediate and normal components in levels 14-8 was consistent with sampling a time near the Brunhes-Matuyama transition from reversed to normal polarity. Viable magnetostratigraphic samples were impossible to obtain above level 8 because of the friable sediments.

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