Diagenesis processes

As shown in the discussion accompanying Figure 7.4, sulfate is reduced before methane is generated in the diagenesis process. At the subsediment SMI, sulfate from the seawater above, and methane from the dissolved (or free) gas below, are consumed to produce carbonate and hydrogen sulfide. The anaerobic reaction for... 

Pingitore N.E. (1976) Vadose and phreatic diagenesis Processes, products and their recognition in corals. J. Sediment. Petrol. 46, 985-1006. 

Diagenesis processes that alter the structure, texture, and mineralogy of a sediment, turning it progressively into solid hard rock early diagenesis occurs immediately after deposition or burial of the sediment. 

Cubic close packing arrangement of atoms in a crystal in their closest possible way having cubic symmetry Diagenesis process that affects a sediment while it is at, or near, the Earth s surface (caused by temperature and pressure) Dyke a vertical sheet of igneous rock extruded into an existing rock... 

Petersen W., Wallmann K., Li P. L., Schroeder F., and Knauth H. D. (1995) Exchange of trace-elements at the sediment-water interface during early diagenesis processes. Mar. Freshwater Res. 46, 19-26. 

Diagenesis process leading to changes in a sediment after deposition at low temperatures and pressures less drastic than metamorphism (q.v.)... 

Fig. 3.1 Concentration profiles in the pore water fractions of sediments obtained off the estuary of the River Congo, at a depth of approximately 4000 m. The sediments contain a relatively high amount of TOC. Values ranging from 1 to 3.5 wt. % indicate that this sediment is characterized by the high reaction rates of various early diagenesis processes. These processes are reflected by diffusion fluxes over gradients and by reaction rates determined by gradient changes (after Schulz et al. 1994).

The processes of early diagenesis - irrespective of whether we are dealing with microbiological redox-reactions or predominantly abiotic reactions of dissolution and precipitation - are invariably reflected in the pore water of sediments. The aquatic phase of the sediments is the site where the reactions occur, and where they become visible as time-dependent or spatial distributions of concentrations. Thus, if the early diagenesis processes are to be examined and quantified in the young marine sediment, the foremost step will always consist of measuring the concentration profiles in the pore water fraction. 

P04, namely from overlying water to sediments. The different diffusing directions reflected their different early diagenesis processes in the sediments (Song, 1997b). 

Soetaert, K. Herman, P. M. J. Middelburg, J. J. (1996) A model of early diagenesis processes from the shelf to abyssal depths. Geochim. Cosmochim. Acta 60(6), 1019 1040. 

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