Figure F1. Pore water CH4, SO42–, alkalinity, Mg2+, and Ca2+ profiles at ODP Site 994, outer Blake Ridge (Paull, Matsumoto, Wallace, et al., 1996). Note the convergence of linear CH4 and SO42– profiles at the sulfate–methane transition (SMT) and the drops in alkalinity, Mg2+, and Mg/Ca beneath the SMT. This zone contains authigenic Mg-rich carbonate, specifically dolomite at Site 994 (Rodriguez et al., 2000).

Figure F1. Pore water CH₄, SO₄^2–, alkalinity, Mg²⁺, and Ca²⁺ profiles at ODP Site 994, outer Blake Ridge (Paull, Matsumoto, Wallace, et al., 1996). Note the convergence of linear CH₄ and SO₄^2– profiles at the sulfate–methane transition (SMT) and the drops in alkalinity, Mg²⁺, and Mg/Ca beneath the SMT. This zone contains authigenic Mg-rich carbonate, specifically dolomite at Site 994 (Rodriguez et al., 2000).