国際標準模式層断面及び地点
The base of the Messinian is at the first appearance of the planktonic foram species "Globorotalia conomiozea" and is stratigraphically in the middle of magnetic chronozone C3Br.1r. The Global Boundary Stratotype Section and Point for the Messinian is located in a section at Oued Akrech, near the Moroccan capital Rabat.