Laverne, Christine (1983): Geochemistry and minerals at DSDP Hole 70-504B. PANGAEA, https://doi.org/10.1594/PANGAEA.816486, Supplement to: Laverne, C (1983): Occurrence of melanite and aegirine-augite in Deep Sea Drilling Project Hole 504B. In: Cann, JR; Langseth, MG; Honnorez, J; Von Herzen, RP; White, SM; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 69, 593-605, https://doi.org/10.2973/dsdp.proc.69.133.1983
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In three veins from the lower part of Deep Sea Drilling Project Hole 504B, 298 meters below the top of basement, primary augite is replaced by aegirine-augite. This transformation occurs only in subophitic basalts, at the contact with veins which always include a dark-olive, Mg-rich clay mineral.
Talc occurs in one of these veins; it can be regarded either as a vein constituent or as a product of augite alteration.
Melanite (Ca,Fe,Ti-rich garnet) appears in only one of these three veins, where a Ca-carbonate is associated with a Mg-rich clay mineral. The occurrence of melanite in Hole 504B could be due to the conjunction of particular conditions: (1) basalt with a subophitic texture, (2) presence of hydrothermal fluids carrying Ca, Fe, Si, Ti, Al, Mg, and Na, (3) rather high temperatures. Possibly the melanite and aegirine-augite formed by deuteric alteration.
Median Latitude: 0.613500 * Median Longitude: -41.865000 * South-bound Latitude: 0.000000 * West-bound Longitude: -83.730000 * North-bound Latitude: 1.227000 * East-bound Longitude: 0.000000