Figure 26. Hypothesis of silicate expansion in subsurface waters during the Matuyama Opal Maximum (MOM). A. Present-day distribution patterns of silicate at 100 m (simplified from Herzfeld and Berger, 1993). Gray = silicate content >4 µM/kg; black = >8 µM/kg. B. Hypothetical conditions during MOM time, near 2.2 Ma. Currents: SAC = South Atlantic Current, BC = Benguela Current, PUC = Poleward Undercurrent, AgR = Agulhas Retroflection, and AAE = Antarctic water excursions.

Figure 26. Hypothesis of silicate expansion in subsurface waters during the Matuyama Opal Maximum (MOM). A. Present-day distribution patterns of silicate at 100 m (simplified from Herzfeld and Berger, 1993). Gray = silicate content >4 µM/kg; black = >8 µM/kg. B. Hypothetical conditions during MOM time, near 2.2 Ma. Currents: SAC = South Atlantic Current, BC = Benguela Current, PUC = Poleward Undercurrent, AgR = Agulhas Retroflection, and AAE = Antarctic water excursions.