This dataset contains potential ex-situ microbial methanogenesis and sulfate reduction rates determined with radiotracer techniques (¹⁴C-bicarbonate and ³⁵S-sulfate incubations, respectively) in sediment slurries (sediment mixed with artificial seawater). Minimum biological quantification limit was 0.09 pmol CH₄ cm⁻³ d⁻¹ and 0.13 pmol SO₄²⁻ cm⁻³ d⁻¹, respectively. Ex-situ incubation temperatures were 40°C for samples from depths ≤360 mbsf, 60°C for for samples from 405–585 mbsf, 80°C for for samples from 604–775 mbsf and 95 °C for for samples from ≥816 mbsf. Methanogenesis samples where amended with hydrogen (130 nmol L⁻¹). Sulfate Reduction samples where amended with hydrogen (130 nmol L⁻¹), acetate (5 mmol L⁻¹), or methane (100% headspace). Incubation times were up to 10 days. For more details on incubation and analytical procedures see related publications.