Leg 76 sampled 31.5 m of basaltic basement at Deep Sea Drilling Project Hole 534A in the Blake-Bahama Basin. The basalts represent a short section of mineralogically uniform, sparsely plagioclase-phyric pillow flows, composed mainly of plagioclase, augitic clinopyroxene, iron-titanium oxides with variable amounts of alteration products (smectite ± carbonate ± quartz). Their major element chemistry is typical of mid-ocean ridge tholeiites and has normative compositions of olivine tholeiites. Mg/(Mg + Fe**2+) ratios range from 0.58 to 0.60, which suggests that these basalts are evolved compared to primitive mantle melts.

Supplement to: Logothetis, John (1983): Petrography, mineralogy, and geochemistry of basalts from Hole 534A, Leg 76. In: Sheridan, RE; Gradstein, FM; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 76, 713-717