The present contribution examines the relationship between pressure solution and the crystallographic orientation of detrital quartz in cleaved sandstones which exhibit a high degree of pressure solution. The majority of the detrital grains examined have undergone pressure solution and as a result they have acquired smooth truncated margins along certain cleavage planes. The amount of pressure solution varies significantly among the detrital grains. This analysis indicates that quartz offers variable resistance to pressure solution along different crystallographic directions. Quartz grains with a small angle between c-axis and the Z-axis of shortening exhibit the least amount of pressure solution, whereas grains with oaxes oriented about 50° to Z manifest the highest degree of the pressure solution.

By measuring the degree of flattening and the orientation of the c-axis of single quartz grains in a naturally deformed ("cleaved") sandstone, Becker (1995) showed that: "quartz grains with a small angle between c-axis and the Z-axis of shortening exhibit the least amount of pressure solution, whereas grains with c-axes oriented at about 50° to Z manifest the highest degree of pressure solution". I briefly present some experimental results that show exactly the same. <...>