In Snake Pit massive sulfide fragments and friable, unconsolidated material recovered during ODP Leg 106, isocubanite and pyrite are generally the predominant phases, followed by marcasite, chalcopyrite, sphalerite, and pyrrhotite. Detailed analyses of paragenetic relations of minerals indicate that isocubanite first precipitated together with pyrrhotite. With decreasing temperature, chalcopyrite and sphalerite precipitated, and at the latest stage colloform sphalerite-pyrite (or colloform marcasite) formed. Isocubanite usually has exsolution lamellae of chalcopyrite and less commonly of pyrrhotite.The average bulk chemical composition of the friable, unconsolidated material indicates that it is rich in copper, reflecting the dominance of isocubanite in the specimens, and is characterized by high Co, low Pb, and Ag contents. Sulfur isotope ratios are very uniform, ranging in d34S from +1.2 to +2.8 per mil. The obtained values are apparently low, compared to those for the eastern Pacific sulfide samples, reflecting a smaller contribution of seawater sulfate in the Snake Pit sulfide deposit.

Supplement to: Kase, Katsuo; Yamamoto, Masahiro; Shibata, Tsugio (1990): Copper-rich sulfide deposit near 23°N, Mid-Atlantic ridge: chemical composition, mineral chemistry, and sulfur isotopes. In: Detrick, R; Honnorez, J; Bryan, WB; Juteau, T; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 106/109, 163-177