Figure 5. Stratigraphic variation in the ratio of the red (650 nm) to blue (450 nm) wavelengths at Holes 1076A, 1076C, and 1076D, displaying a pronounced periodicity possibly corresponding to the 23-k.y. precession cycle. Data have been smoothed over nine points for Hole 1076A and over five points for Holes 1076C and 1076D.

Figure 5. Stratigraphic variation in the ratio of the red (650 nm) to blue (450 nm) wavelengths at Holes 1076A, 1076C, and 1076D, displaying a pronounced periodicity possibly corresponding to the 23-k.y. precession cycle. Data have been smoothed over nine points for Hole 1076A and over five points for Holes 1076C and 1076D.