Stratigraphy

In stratigraphy, chronology is presented in two aspects:  • Relative, which makes it possible to organise geological structures and events in relation to each other over time, by giving them a relative age. This relative dating is based on fundamental principles of stratigraphy. The stratigraphic scale of geological time is established from the lithological data (lithostratigraphy) and palaeontological content (biostratigraphy) of the different layers of terrain. • Absolute, allowing the exact or numerical age of rocks or geological events to be assigned