The structure contains a thick sedimentary sequence of sandstone, shale and siltstone.

In a sedimentary sequence the associated material within the ash layer can be dated, giving a date for the eruption.

In the case of a rift, for instance, the sedimentary sequence is normally broken down into three parts:

This is largely because of its enormous potential for dating geological processes and sedimentary sequences.

The depositional environments of the killas were very varied, as is revealed by the fossil content and the sedimentary sequences.

The sedimentary sequences of the Paleocene highlight the differences between the eastern and the western Pyrenees.

Erosion, earthquakes, volcanoes and other earth movements often disturb, remove, or even overturn a sedimentary sequence.

Some include sedimentary or rift-volcanic sequences that have been interpreted as passive margins prior to metamorphism.

On the Aleutian side, the ridge is rimmed by a trough filled with a sedimentary sequence 9-10 km thick.

The sedimentary sequence is assumed to be continuous from the Ediacaran to the Visean (330 million years ago).