DETERMINATION OF PRESSURE SOLUTION SHORTENING IN SANDSTONES

A new method for the determination of pressure solution shortening in sandstones uses the geometry of grain-to-grain interpenetrations and g rains truncated against solution surfaces. These features are used to construct plots from which the magnitude and direction of the pressure solution shortening can be determined. Using simulated pressure solut ion deformation of artificial and natural grain populations, the new m ethod is shown to correctly assess a variety of coaxial and non-coaxia l shortenings. Although primarily intended to determine shortening, th e method can also quantify extension related to growth of beards or ov ergrowths during pressure solution. Application of the method to natur ally deformed quartz arenite samples shows that pressure solution shor tening of up to 26% occurred during compaction and 22% during layer-pa rallel shortening.