DISCUSSION AND CONCLUSIONS

Our ¹⁸O, inorganic carbon, and nannofossil data suggest that the oldest sediments in core GC-10 are from MIS 6 (130–140 ka; Fig. F4), whereas all other cored sediments are within the E. huxleyi acme Zone and are thus younger than 85 ka. The proposed age model based on nannofossil and isotope data correlates well with carbonate content and sediment color, which fits into a depositional model reflecting glacial–interglacial cycles. All glacial stages (2, 4, and 6) in core GC-10 (Fig. F4) coincide with low carbonate contents and darker sediment color. This matches other studies in periplatform slope settings (e.g., Betzler et al., 1999; Isern and Anselmetti, 2001), where sea level lowstands resulted in a relative increase in siliciclastic input because carbonate production was reduced.

The sedimentation rate for core GC-10 is 3 m per 85 k.y. or 3.5 cm/k.y. The other gravity cores have average rates as low as 2.6 cm/k.y. Because the longest core (GC-10) was taken at a location that was not drilled during Leg 194, no direct comparison can be made with the sedimentation rates of the underlying Neogene section. However, these values approximately match the youngest sedimentation rate values obtained from nearby Sites 1192 (~20 m/m.y.) and 1198 (~50 m/m.y.) (Isern, Anselmetti, Blum, et al., 2002). This indicates that the overall sedimentation pattern has not changed as a result of infilled morphology and/or modern current patterns.