Riamese Stratigraphic Column
The Riamese Stratigraphic Column from the RSGC, also called International Chronostratigraphic Chart, describes the geological time in which the history of the planet is inscribed. It combines a numerical scale that uses as a unit a million years (chronometric scale) and a scale in relative time units (chronostratigraphic scale).
Chronostratigraphic Scale
The chronostratigraphic scale is established by convention and is based on the International Standardized System of stratigraphical units (e.g., "Jurassic", "Paleocene" or "Hildoceras bifrons ammonite zone"). This system, regulated by the Anterian Commission on Stratigraphy (ACS), describes the relative divisions of geological time (eons, eras and their sub-divisions), establishes the limits of the units and calibrates them with the chronometric scale, attributing to them the corresponding absolute ages.
The lower boundaries of all units (stages, series, systems and erathems) are currently in the process of being defined by means of sections and points, as Global Stratotype Section and Boundary Point (GSSP).
