Paleomagnetic Polarity Research of Paleobiology Boundary (Bed 27) of Meishan, Changxing, Zhejiang Province

The magnetostratigraphic sampling was carried out respectively in the inside part (14 cm away from the section surface along the bed) and outside part (5 cm away from the section surface along the bed) with no interval at the same bed (Bed 27) which the paleobiology boundary (PBB) of A and D sections lies in of Meishan, Changxing. This research shows that the deep samples suffered slighter secondary magnetization than the shallow ones did and in comparison with D section's samples, the samples of A section sustained slighter secondary magnetization. On the bases of the data, the secondary magnetization influence of which is relatively weak, this paper obtains the conclusion that the bed, in which the paleobiology boundary lies, lies within the reverse polarity subzone.