GSSP (Global Boundary Stratotype Section and Point)

A GSSP, or Global Boundary Stratotype Section and Point, is an internationally agreed-upon reference marker that defines the beginning of a specific geological time period or event. It is a specific location and point in the Earth's rock record, carefully chosen because it contains clear, recognizable features—such as unique fossils or chemical signatures—that distinctly mark the boundary. GSSPs ensure that geologists worldwide can reliably identify and correlate these boundaries across different regions, helping us organize Earth's history with precision and consistency.