Figure F6. A. Smear slide of the solid residue remaining after a 9-hr 2-M Na2CO3 extraction of a 46-Ma sample from DSDP Site 162 (14-4: 80-81 cm). Dissolved SiO2 = 19.2 wt% (#1576, slide 50). B. Residue remaining after a 9-hr 2-M KOH digestion of a 46-Ma sample from DSDP Site 162 (14-4: 80-81 cm). Note the dissolution-resistant opal fragments. Dissolved SiO2 = 37.1 wt% (#1578, slide 51R).

Figure F6. A. Smear slide of the solid residue remaining after a 9-hr 2-M Na₂CO₃ extraction of a 46-Ma sample from DSDP Site 162 (14-4: 80-81 cm). Dissolved SiO₂ = 19.2 wt% (#1576, slide 50). B. Residue remaining after a 9-hr 2-M KOH digestion of a 46-Ma sample from DSDP Site 162 (14-4: 80-81 cm). Note the dissolution-resistant opal fragments. Dissolved SiO₂ = 37.1 wt% (#1578, slide 51R).