Uber Hiatus-Konkretionen (dargestellt an Beispielen aus dem Lias)

Calcareous concretions from the middle Lias (Domerian) of Northern and Southern Germany revealing growth in several phases conditioned by interruptions of sedimentation or by coalescence of concretions of different age are called Hiatus Concretions. The hiatuses are proved by the fact that these concretions, which were formed in the sediment by early diagenetic processes, were washed out and are corroded or bored on the surface and encrusted by oysters, serpulids, bryozoans or other sessile benthonic organisms.

After a new beginning of sedimentation the growth of the concretions started again. By this process the younger concretions included the older ones which often were the starting point for a new generation of concretions.

In section the ancient surfaces with incrusting shells can be observed