Stress differential

Protein swelling Differential stress due to rapid dehydration Changes in lipid fluidity... 

The differential stress also correlates with the subgrain size d and with the size D of the grains generated by dynamic recrystallization. The empirical relations... 

Kohlstedt, D. L., Weathers, M. S. (1980). Deformation induced microstructures, paleopiezometers and differential stress in deeply eroded fault zones. J. Geophys. Res., 85, 6269-85. 

Xenoliths most commonly show coarse or porphyroclastic textures, or some continuum between the two. The former is defined by a grain size of greater than 2 mm (Table 2) and is commonly equigranular (Figure 1(a)). This texture represents a stable grain size developed under differential stresses that are small and constant over milhons of years in the lithosphere. The grain size in olivine, the most abundant but weakest mineral in peridotite xenoliths, can be a measure... 

Etheridge M. A. (1983) Differential stress magnitudes during regional deformation and metamorphism upper bound imposed by tensile fracturing. Geology 11, 213-234. 

Fig. 7. Tectonic interpretation showing accretion of mafic and ultramafic oceanic sequences, juvenile volcanic arcs, and accretionary prisms against an older crustal nucleus. Inset shows strength envelopes for the lithosphere showing differential stress (oj-as, MPa) against depth (km) for granite, granulite and dunite (see Jelsma et al. 2001) and Byerlee s (1978) friction relation.

The main micro-scale controls on dilatancy during shear failure in shales can be described by considering the processes taking place in a stressed rock element. Strain begins to localise in the sample at peak differential stress and this leads to the formation of undulating shear zones (shear fractures). Sliding on... 

Lockner, D. and Byerlee, J.D. 1977. Hydrofracture in Weber sandstone at high confining pressure and differential stress. J. Geo-phys. Res., 82 2018-2026. 

Sink/ sourcs metabolism Cell division, differentiation Stress defense... 

The second mechanism is dilation/contraction induced permeability change during shear (Figure 1 (b)). Fractures dilate when fracture failure occurs under high differential stresses. This mechanism can play a major role in the flow field since the dilated fracture tend to have much higher transmissivity than the fracture under elastic deformation. 

Figure 7. Permeability change due to the change of differential stress.

---