Figure F21. Selected time series records from Sites 1123 (water depth = 3290 m; North Chatham Drift) and 1124 (water depth = 3967 m; Rekohu Drift). A. Middle Miocene (12.5-15.5 Ma) sortable silt (SS) record from Site 1123 and its filtered 41-k.y. orbital obliquity component plotted against the geomagnetic polarity and Site 1123 timescales. The filter has a central frequency of 0.04065 cycles/k.y. and a bandwidth of 0.01046 cycles/k.y. (after Hall et al., 2003). Note the way that these two records vary in close sympathy with each other, with enhanced Deep Western Boundary Current flow (increased mean grain size of sortable silt) corresponding to obliquity maxima. B. Post-Pliocene (0-3.0 Ma) records of benthic

Figure F21. Selected time series records from Sites 1123 (water depth = 3290 m; North Chatham Drift) and 1124 (water depth = 3967 m; Rekohu Drift). A. Middle Miocene (12.5-15.5 Ma) sortable silt (SS) record from Site 1123 and its filtered 41-k.y. orbital obliquity component plotted against the geomagnetic polarity and Site 1123 timescales. The filter has a central frequency of 0.04065 cycles/k.y. and a bandwidth of 0.01046 cycles/k.y. (after Hall et al., 2003). Note the way that these two records vary in close sympathy with each other, with enhanced Deep Western Boundary Current flow (increased mean grain size of sortable silt) corresponding to obliquity maxima. B. Post-Pliocene (0-3.0 Ma) records of benthic

¹⁸O for Site 1123 (above) and carbonate:terrigenous ratio for Sites 1123 (middle) and 1124 (below). Thick lines indicate a 50-point moving average, to better show the general similarity between the profiles through time (after Hall et al., 2002). Note the presence of enhanced terrigenous ratios and wider fluctuations in ratios from about 1.4 Ma onward, in correspondence with the enhanced amplitude then of the benthic oxygen isotope signal. C. Pleistocene (0-1.2 Ma) records from Site 1123 for benthic

¹⁸O (above), benthic

¹³C (middle), and mean grain size of sortable silt (SS) below (after Hall et al., 2001). Note the correspondence between glacial climates and enhanced Deep Western Boundary Current flow (DWBC). MIS = marine isotope stage.