Diagenesis at exposure surface in transgressive systems tract in third order sequence (Lower Carboniferous, Belgium)

This chapter determines the influence of exposure surfaces with possible influx of meteoric waters on the exposed limestone and its effect on porosity and cementation history. The small scale sequences that belong to the lower part of the transgressive systems tract (TST) show a diagenetic evolution starting with marine cementation with fibrous and pendant radiaxial cements that is best developed near the top of the sequences due to evaporation of marine waters. The third order, type 1 sequence boundary caused the pervasive cementation of almost all initial porosity in the limestone below the boundary due to a prolonged exposure. The chapter demonstrates that short-term exposure seems to be more effective than longer exposure in creating porosity in limestone sequences.