DIFFERENTIAL DISSOLUTION: MODIFICATION OF LATE PLEISTOCENE OXYGEN ISOTOPE RECORDS IN THE WESTERN EQUATORIAL PACIFIC

Deep-sea records of the Pacific Ocean show dramatic variations in the dissolution intensity of calcium carbonate through the late Pleistocene. Extremes are characterized by much depressed dissolution intensity during deglaciation (preservation spikes) and much enhanced dissolution intensity during ice growth (dissolution spikes). Increased dissolution intensity at dissolution spikes distorts delta O-18 records by preferential removal of O-16-rich shells, resulting in heavier delta O-18 values at theses sections. The delta O-18 values tend to remain unaltered at deglacial preservation spikes. Thus the fluctuations of carbonate dissolution intensity modify the late Pleistocene oxygen isotope records in such a fashion that apparent "climate optima" (as defined by the lightest delta O-18 values) tend to shift toward preservation spikes, while apparent "glacial maxima" (characterized by the heaviest delta O-18 values) shift toward dissolution spikes.