(Woods Hole Oceanographic Institution, 1976-03)
Peters, Christopher S.
The purpose of this study is to evaluate the effectiveness of oxygen isotopic analysis in establishing a late Pleistocene stratigraphy in two cores (CHN 115-88 and CHN 115-89) from the Verna Channel. Glacial and interglacial stages and stage boundaries in the two cores were identified, based on fluctuations in the 018 curves obtained by analysis of bulk foraminiferal assemblages. The position of the Brunhes/Matuyama boundary near the base of both cores provided an estimate of average accumulation rates of 0.94 cm/103 years in core 88, and 0.86 cm/103 years in core 89.
The δ 018 curve for core 88 indicates a continuous stratigraphic record of glacial and interglacial stages as far back as stage 20; stages in core 89 are identifiable as far as stage 12. Stratigraphic
interpretation within the top portion of the cores is somewhat uncertain, possibly due to disturbed or missing sediment. variability in accumulation rates down-core, and the possibility of missing coretop sediment, contribute to the uncertainty in stage designations. The degree of variability of accumulation rates within cores 88 and 89 may be estimated by assuming a constant sedimentation rate, and then comparing the "time scale" of the stage boundaries with that of Shackleton and Opdyke (1973).
The results indicate that oxygen isotopic analysis of bulk foraminiferal assemblages can provide reliable interpretations in some instances where analysis of monospecific assemblages is not possible. Analysis of monospecific assemblages, however, will be required for more precise and reliable paleoclimatic interpretations.
