ODP Leg 174A: Mid-Atlantic Sea-Level Transect

Arrows mark interpreted lithologic cycles seen in the Pleistocene (Plio-Pleistocene boundary at ~520 mbsf). The cycles correspond to abrupt decreases in clay content followed by gradual upward increase in clay, and are interpreted to reflect changes in sealevel. These cycles match closely the changes in grain size seen in the core as well as changes in the pore water chemistry. An abrupt reversal in velocity and resistivity in the condensed sedimentation interval below the Pleistocene suggests underconsolidation and possible overpressure associated with the rapid emplacement of the Pleistocene Hudson Apron sediments