International Commission on Stratigraphy

A global effort to standardize international stratigraphic nomenclature is being conducted by the International Commission on Stratigraphy (ICS), the largest scientific body within the International Union of Geological Sciences (IUGS). It is also the only organization concerned with stratigraphy on a global scale. The ICS is in the process of standardizing the Geological Time Scale, a task that is to be completed by 2008. A major purpose of the ICS is to establish global stage boundaries called Global Stratotype Sections and Points (GSSP's).

International Union of Geological Sciences--The IUGS is one of the largest non-governmental scientific organizations in the world. IUGS keeps a non-political and non-governmental stance and is a non-profit making organization. With 116 member countries and 38 affiliated organizations, IUGS represents about 250,000 Earth scientists worldwide.

The Union's journal is Episodes (http://www.episodes.org/).
IUGS website is http://www.iugs.org/.

Global Stratotype Section and Point (GSSP)--The basal boundary of each global stage in this international geologic scale is standardized at a Global Boundary Stratotype Section and Point (GSSP). A GSSP is a point in a single reference section within an interval exhibiting continuous sedimentation that was selected by international agreement as the primary reference level for the geologic state. http://www.stratigraphy.org/gssp.htm

Standard Geologic Time Scale--The Stratigraphic Chart provides a universal language for geo-history and includes a succession of global rock units, the stages, formed during specific intervals of geologic time. It is produced by the International Commission on Stratigraphy under IUGS and is the result of many years of work by thousands of stratigraphers all over the world in their endeavor to relate rock with time. The Geologic Time Scale 2004 (GTS 2004) by Gradstein et al. (2004) is the successor to GTS 1989 (Harland et al., 1990), which in turn was preceded by GTS 1982 (Harland et al., 1982). GTS 2004 also replaces the International Stratigraphic Chart 2000 of the International Commission on Stratigraphy (ICS) and UNESCO (Remane, 2000). The 2004 International Stratigraphic Chart is available at http://www.stratigraphy.org/cheu.pdf (PDF file).

The Stratigraphic Chart is based on the sequence of these GSSP's. The chart is continually updated (available at www.stratigraphy.org). The third edition with 2/3rds of the international geologic stages standardized by GSSP's at their bases was printed in connection with the International Geological Congress in Florence in 2004.

This standardization of the international stratigraphic chart by GSSP's and ratified nomenclature for units of geologic time will be completed by 2008.