Diagenetic stage
Compaction has affected the sandstones of the studied
Miocene formations to a great degree. The nature of the grain
contacts in many samples is evidence of compaction. In many
cases, the contacts are longitudinal and sutured, and the edges
of three or more grains meet at a common point (Figs. 5 and
6). In addition, pressure solution is a common feature, with
harder grains such as chert and quartz being in contact with
softer carbonate grains.