Magnetostratigraphy of ODP Leg 105 sites

Intermittent recovery and drilling disturbance, resulting in part from the harsh weather conditions encountered, hampered magnetostratigraphic study. In particular, incomplete recovery of undisturbed sediment and sparse biostratigraphic control make it difficult to correlate the polarity zones observed in sediments recovered at Site 645 in Baffin Bay with the geomagnetic polarity time scale.

However, the undisturbed Pliocene-Pleistocene sediments recovered using the advanced piston corer (APC) at Sites 646 and 647 yield polarity sequences that are readily correlated with the time scale. Deeper sequences cored using the extended core barrel (XCB) corer at Site 646 provide a coarse polarity sequence that, in conjunction with the available biostratigraphic data, may be correlated tentatively with late Miocene reversal sequences.