Pore water studies enable (1) the detection of diagenetic reactions actively occurring in the sediment atthe time of sampling,(2) the distinction between principal modes of solute transport, i.e., between advection(convection) and diffusion, and (3) the assessment of mineral-solution equilibria, Pore waters are, therefore,preferred diagnostic objects in the study of diagenesis, particularly early diagenesis. The single most important factor for pore-fluid evolution in modern offshore basins is sedimentationrate which is closely correlated with organtic matter content of the sediment. Organic matter represents themost reactive sediment constituent which, through bacterial decomposition, provides some of the mainsolutes involved in early diagenetic mineralization reactions. On the basis of sedimentation rate and organicmatter content, it is convenient to distinguish two end-members of basins (environments) with respect toearly diagenesis: Ⅰ. Low to in termediate-sedimentation rate basins with convection or diffusion-controlledpore-water profiles and Ⅱ. high-sedimentation rate basins with reaction-controlled pore-water profiles. The first group of basins or environments, which is the subject of this paper, is typically represented bypelagic sediments. Three principally different trends of pore-water evolution occur: 1. convection-controlledprofiles with no pronounced vertical gradients for the dissolved species; 2. diffusion-controlled profiles withvertical gradients but linear correlations between major ions, especially Ca and Mg, and 3. profiles withgradients but no linear correlation between the major ions. The later are transitional to the trends seen inhigh-sedimentation rate basins. With respect to redox-potentials, the diagenetic environments of low-sedimentation rate basins are generally oxic to suboxic. Pore ​​water studies enable (1) the detection of diagenetic reactions actively occurring in the sediment atthe time of sampling, (2) the distinction between principal modes of solute transport, ie, between advection (convection) and diffusion, and (3) the assessment of mineral-solution equilibria, Pore waters are, therefore, preferred diagnostic objects in the study of diagenesis, particularly early diagenesis. The single most important factor for pore-fluid evolution in modern offshore basins is sedimentationrate which is closely correlated with organtic matter content the sediment. Organic matter represents themost reactive sediment constituent which, through bacterial decomposition, provides some of the mainsolutes involved in early diagenetic mineralization reactions. On the basis of sedimentation rate and organicmatter content, it is convenient to distinguish two end-members of basins ( environments) with respect toearly diagenesis: I. Low to in termediate-sedimentation rate basi ns with convection or diffusion-controlledpore-water profiles and II. high-sedimentation rate basins with reaction-controlled pore-water profiles. The first group of basins or environments, which is the subject of this paper, is preferably represented bypelagic sediments. Three principally different trends of pore-water evolution occur: 1. convection-controlledprofiles with no pronounced vertical gradients for the dissolved species; 2. diffusion-controlled profiles withvertical gradients but linear correlations between major ions, especially Ca and Mg, and 3. profiles withgradients but no linear correlation between the major ions. The later are transitional to the trends seen in high-sedimentation rate basins. With respect to redox-potentials, the diagenetic environments of low-sedimentation rate basins are generally oxic to suboxic.