Marine sediment properties

The environmental relevance of anaerobic degradability as a property for surfactants is driven by the amount that can accumulate and potentially cause effects in anaerobic environmental compartments such as continental or marine sediments. Due to their hydrophobic... 

Natural carbonate minerals do not form from pure solutions where the only components are water, calcium, and the carbonic acid system species. Because of the general phenomenon known as coprecipitation, at least trace amounts of all components present in the solution from which a carbonate mineral forms can be incorporated into the solid. Natural carbonates contain such coprecipitates in concentrations ranging from trace (e.g., heavy metals), to minor (e.g., Sr), to major (e.g., Mg). When the concentration of the coprecipitate reaches major (>1%) concentrations, it can significantly alter the chemical properties of the carbonate mineral, such as its solubility. The most important example of this mineral property in marine sediments is the magnesian calcites, which commonly contain in excess of 12 mole % Mg. The fact that natural carbonate minerals contain coprecipitates whose concentrations reflect the composition of the solution and conditions, such as temperature, under which their formation took place, means that there is potentially a large amount of information which can be obtained from the study of carbonate mineral composition. This type of information allied with stable isotope ratio data, which are influenced by many of the same environmental factors, has become a major area of study in carbonate geochemistry. 

Figure 8.25. Some chemical and diagenetic properties of organic-rich marine sediments as a function of depth based on DSDP interstitial water profiles. A. Schematic gradients of SO42-, total alkalinity, Ca2+ and Mg2+ in pore waters, and zones of sulfate reduction, methanogenesis and fermentation. Magnesium diffuses into the sediment and organogenic dolomite forms at depth. B. Logarithm of calculated saturation states of interstitial waters with respect to dolomite. Dolomite saturation=0. All these pore waters are oversaturated with respect to dolomite. (After Compton, 1988.)...

Aller, R.C. (1982) The effects of macrobenthos on chemical properties of marine sediment and overlying water. In Animal-Sediment Relations (McCall, P.L., and Tevesz, M.J.S., eds.), pp. 53-102, Plenum Press, New York. 

Weiler, R.R., and Mills, A.A. (1965) Surface properties and pore structure of marine sediments. Deep-Sea Res. 12, 511-529. 

Many rock types have a layered structure, individual rock layers varying in thickness from a few centimeters to tens of meters. Layered rocks include marine sediments, most continental sediments, lava flows and volcanic ejecta, and intrusive sills. The hydraulic properties vary from one rock layer to another, often resulting in abrupt changes along the vertical axis. In terms of the permeability coefficient (k) the lateral coefficient (kx) may significantly differ from the vertical coefficient (kz). The alternation of aquifers and aquicludes results from the layered structure of different rocks, and the occurrence of springs is often controlled by the layering of rocks. Fissures may be restricted to individual rock layers or cross several rock beds, in which case water flow is improved, mainly in the vertical direction. 

Tribble J. S., Mackenzie F. T., Urmos J., O Brien D. K., and Manghnani M. H. (1992) Effects of biogenic silica on acoustic and physical properties of clay-rich marine sediments. Am. Assoc. Petrol. Geol. Bull. 76, 792-804. 

Humic substances in marine sediments originate from both marine and terrestrial sources of organic matter, depending on the nature of sedimentary input. In some cases, a set of criteria based on chemical properties makes it possible to determine their origin. However, these criteria are less clear-cut than those established for kerogens. 

Grim, R.E., 1939. Properties of clays. Recent Marine Sediments. AAPG, Tulsa, pp. 466-495. 

One of the most important anaerobic pathways of decomposition in marine sediments is sulfate reduction (Berner, 1964 Goldhaber and Kaplan, 1974 J0rgenson, 1977). Proof that sulfate reduction is taking place in surface sediments at each station of this study comes from the abundance of fixed sulfur in the solid phase and the presence in the pore waters of dissolved sulfide (Figs. 31-34 Appendix B Goldhaber et ai, 1977). Because sulfate reduction presumably dominates the anaerobic decomposition reactions over most of the sampled sediment regions, reaction 5 of Table IV will be assumed as the major model reaction to aid in the interpretation of pore-water and solid-phase property distributions. Additional decomposition reactions involving sulfide oxidation, specific interaction with Fe and Mn oxides, and fermentation (Presley and Kaplan, 1968) occur, but will not be emphasized here. 

Sepiolite/ Palygorskite Phyllosilicates Marine sediments, arid soils, high Si and Mg levels R Moderately high CEC.15 surface area, and sorptive properties... 

In the shallow regions of the Athabasca deposit, the oil is in a drainage basin that was filled in with sediments as it was alternately flooded by a sea (estuarial environment) and then rivers (fluvial environment), so that a number of distinct depositional environments of estuarine and marine sediment occurred (10—15). As a result, the oil-bearing sands have great variability in their compositions and properties. 

Generally, physical properties of marine sediments are good indicators for the composition, microstructure and environmental conditions during and after the depositional process. Their study is of high interdisciplinary interest and follows various geoscientific objectives. 

Physical properties of marine sediments depend on the properties and arrangement of the solid and flnid constituents. To fully understand the image of geological and paleoceanographical processes in physical property core logs it is helpful to consider the single components in detail (Fig. 2.1). 

Various methods exist to measure the different physical properties of marine sediments. Some parameters can be measured directly, others... 

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