Similar to joints, pressure solution seams can be considered in several components. The components with smaller length scale are generally linked to grain contacts in rock (Figure 1 and Figure 2). When viewed in the appropriate scale, actual contacts of adjacent grains have detectable roughness resulting in grain contacts at limited areas and open spaces in between the contact areas. The next hierarchical component of any pressure solution is a thin zone of residue representing several merged or linked or coalesced inter-granular pressure solution seams (Figure 2). Pressure solution seams also have many macroscopic segments as discussed under 'Echelon Pressure Solution Seams,' 'Pressure Solution Seam Zones,' and 'Growth of Pressure Solution Seams.'

Figure 1. Secondary electron image of some quartz grains and inter-granular pressure solutions (highlighted by half-transparent, yellow infill). From Nenna and Aydin (2011).

Figure 2. Secondary electron image (a) and false color image (b) of a through going incipient single PSS at high magnification. The seam is identified as a mica- and clay-rich core between multiple truncated quartz grains. Segmented open fractures along the zone are due to a younger deformation phase or thin sectioning. Note the irregular boundaries due to the mergers of lobes of undissolved material to the linear PSS.