Mineralogy and Chemistry of Secondary Phases in Some Basaltic Rocks from DSDP Leg 37

Mineralogy and Chemistry of Secondary Phases in Low Temperature Altered Basalts from Deep Sea Drilling Project Legs 51, 52, and 53

“…In Hole 418A, it is about 15 per cent, while in Hole 417D it is less than 10 per cent. The former could be a more evolved type of palagonite, having undergone a severe leaching of Siθ2 and MgO, similar to those described in other altered pillow basalts (Melson, 1973;Scarfe and Smith, 1977).…”

Secondary Minerals in Some Basaltic Rocks from Deep Sea Drilling Project Legs 52 and 53, Hole 418A

“…These secondary minerals provide evidence for the mechanism and conditions of basalt-sea water interaction, and they may exert important controls on geochemical budgets and the composition of sea water through time (e.g., Scarfe and Smith, 1977b).…”

Secondary Minerals of Basalts from the Nauru Basin, Deep Sea Drilling Project Leg 61

“…Saponite of the first association contains 26.14% MgO, 1.64% Fe 2 O 3 , 0.57% FeO, 4.97% A1 2 O ? , and 0.08% K 2 O. Saponites rich in MgO were found in Leg 37 basalts (Scarfe and Smith, 1977b). The MgO content attributed to saponite is overestimated because of impurities of high-magnesium minerals, e.g., talc in Leg 61 basalts.…”

“…Secondary minerals of the basalt groundmass were formed during the final stages of sill cooling, after their complete solidification, mainly by interaction of interstitial water and primary glass. The possibility of seawater penetration into basement to a depth of 600 meters is shown by Leg 37 basalts (Scarfe and Smith, 1977b;Robinson et al, 1977). Alteration of basalts is possible at low temperatures, about 4°C (Muehlenbachs, 1976;Sey fried et al, 1976).…”

“…Regional alteration of basalt by sea water probably took place at a higher temperature. Scarfe and Smith (1977a) who studied secondary minerals from Leg 37 basalts, also suggested two phases of basalt alteration: one at high temperature, during the solidification of a lava flow, and the other resulting from low-temperature basalt-sea-water interaction.…”