The Global Boundary Stratotype Section and Point (GSSP) for the base of the Valanginian Stage, the Vergol section (Montbrun-les-Bains, Drôme, SE France) and its Standard Auxiliary Boundary Stratotype (SABS), Cañada Luenga section (Cehegín, SE Spain)

Following votes by the Valanginian Working Group, the International Subcommission on Cretaceous Stratigraphy and the International Commission on Stratigraphy, the Executive Committee of the International Union of Geological Sciences unanimously approved in December 2024 the Global Stratotype Section and Point (GSSP) for the Valanginian Stage (Cretaceous System). The base of the Valanginian Stage is defined at the base of limestone bed VGL-B136 of the Vergol section (Montbrun-les-Bains, SE France), and correlated by the First Occurrence of the ammonite species Hoedemaekeria (nov. gen.) pertransiens. Other fossil groups such as calpionellids and calcareous nannofossils are used to characterize the Berriasian/Valanginian boundary. A calibration to the carbon and strontium isotope stratigraphy is also proposed. The age model based on astrochronology allows to date the base of the Valanginian Stage at 137.05 Ma (± 0.2 Ma). Palaeomagnetic investigations reveal that the section is remagnetized and therefore no palaeomagnetic stratigraphy is available. However, an integrated stratigraphy provides an accurate correlation with the Cañada Luenga section (Cehegín, SE Spain), proposed as Standard Auxiliary Boundary Stratotype (SABS), that is characterized by magnetic chrons calibrated by several biostratigraphic scales. The base of the Valanginian Stage falls in the lowermost part of magnetic Chron M14r.