Compaction of sediments

As a result of particle settlement to the sediment-water interface, there is a mass accumulation of sediments which results in compaction of sediments and the physical upward transport or advection of solutes in porewaters to the overlying water. Similarly, solutes in porewaters can also move by diffusion as a result of concentration gradients. Thus, porewaters can be transported by advection from burials, molecular diffusion, and biological pumping or irrigation (Aller, 2001 Jprgensen and Boudreau, 2001). Diffusion in aqueous environments occurs according to Fick s laws of diffusion (Berner, 1980). Fick s first law, used for steady-state conditions, is as follows ... 

Asa result of particle settlement to the sediment-water interface there is a mass accumulation of sediments which results in compaction of sediments and the physical upward transport or advection of solutes in porewaters to the overlying water. Similarly, solutes in porewaters can also move by diffusion as a result of concentration gradients. 

Sedimentary rock a rock formed by compaction of sediment, generally in stratified form. 

Mechanical compaction of sediments includes the rearrangement and breakage of grains which is a function of the overburden stress. Sediment compaction and fluid flow are coupled because the reduction in porosity requires a removal of fluids. 

Experimental compaction of sediments and modelling of chemical compaction may help to predict the physical properties of different lithologies as function of the burial history. This will provide a better basis for the interpretation of the seismic data (Fig 8). 

Traps Resulting from Differential Compaction of Sediments... 

A number of various coring techniques are used to collect lake-sediments (Glew et al., volume 1). The choice of coring technique has to be made with respect to a number of factors like water depth, sediment thickness, type of material, compaction of sediment, etc. With respect to palaeomagnetic measurements (i.e. measurements of the natural remanent... 

Apart from the dimensions of the corer and cutter, it is essential to have well-designed nonreturn valves and sample retainers to minimize the resistance to penetration and prevent the loss of any sediment on recovery. In addition to the disturbance created inside the core barrel, the soil ahead of the advancing corer is subjected to stresses that influence the final core (Kallstenius, 1958). In marine sediments, there is very little scope for compaction of sediments inside the core tube because only a negligible amount of water can be forced out of the material during the short period of time required for penetration (Piggot, 1941 ... 

Meade, R. H. (1966). Factors influencing the early stages of the compaction of clays and sands -review. /. Sediment. Petrol. 36,1085-1101. 

Stability may be inherent or induced. In the latter case, the original system is in a condition of metastable or neutral eouilibrium. External influences which induce instability in a dispersion on standing are changes in temperature, volume, concentration, chemical composition, and sediment volume. Applied external influences consist of shear, introduction of a third component, and compaction of the sediment. Interfacial energy between solid and liquid must be minimized, if a dispersion is to be truly stable. Two complementary stabilizing techniques are ionic and steric protection of the dispersed phase. The most fruitful approach to the prediction of physical stability is by electrical methods. Sediment volumes bear a close relation to repulsion of particles for each other. 

It is recommended to use a borer of diameter greater than 5 cm to avoid column compaction. The sediment columns are mixed and homogenized and a subsample is taken for laboratory analysis. To investigate the vertical distribution of a chemical for... 

Once interpenetration occurs the resistance to deformation increases markedly, so for example we would expect compaction of a sediment to become limited, as would further concentration in a filter press. It is worth emphasising the point that this is a simplistic approach, as prior to interpenetration the clusters undergo structural rearrangements changing their fractal index at a critical volume fraction. A typical data set for yield stress is shown in Figure 6.16.19... 

Studies of the properties of the isolated fragments emphasized the question, Can F2 and F2 acquire their native conformations independently A combination of sedimentation velocity and sedimentation equilibrium studies showed frictional ratios f/f0 of 1.3 and 1.4 for F, and F2, respectively, implying compact globular structures in... 

When sediment settles onto the seafloor, a considerable amount of sediment is trapped between the grains. As discussed in Chapter 12.2.2, pelagic sediments can initially have equal parts of pore water mixed with the solids. As burial progresses, compaction causes the upward vertical advection of pore water, thereby reducing the water content of the... 

Cleanup of sediment samples. The extracted sediment samples were cleaned up using a multilayer column. The multilayer glass column consisted of the following materials (from top to bottom) 1 cm water-free sodium sulfate, 1 g silica, 7 g 44% sulfuric acid on silica, 1 g silica, 2 g 33% sodium hydroxide on silica, 1 g silica, 1.5 g 10% silver nitrate on silica, and a small piece of silanized glass wool. After addition of each layer, the column was compacted by tapping... 

H.H. RIEKE III and G. V. CHILINGA RIAN COMPACTION OF ARGILLACEOUS SEDIMENTS... 

G.V. CHILINGARIAN and K.H. WOLF COMPACTION OF COARSE-GRAINED SEDIMENTS... 

The use of Kollidon CL-M as a suspension stabilizer has nothing whatever to do with the principle of increasing the viscosity. The addition of 5-9% has practically no effect in changing the viscosity, but strongly reduces the rate of sedimentation and facilitates the redis-persability, in particular, an effect that is consistent with the low viscosity. One of the reasons for this Kollidon CL-M effect is its low (bulk) density, which is only half of that of conventional crospovidone, e.g. Kollidon CL. It can clearly be seen from Fig. 5 that a relative volume of sediment of normal micronized crospovidone of high bulk density (= Crospovidone M) is less and more compact that of Kollidon CL-M, which undergoes hardly any sedimentation. 

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