GSSP for Santonian Stage
Definition:
The GSSP for the base of the Santonian Stage is defined at 94.4 m in the eastern border of the “Cantera de Margas” quarry, Olazagutia (Navarra, N. Spain: 42º 52' 05.3" N, 2º 11' 40" W) and marked by the first occurrence of the inoceramid bivalvePlatyceramus undulatoplicatus.
Location:
The Olazagutia section is located in a working quarry to the south of Olazagutia, Navarra, Spain. Its geographical location is 42º 52' 05.3" N, 2º 11' 40" W; Lambert Coordinates 919, 722, 1:25000 topographic sheet no. 113-4 Olazagutia.
Sedimentology:
The section along the disused eastern side of the Cantera de Margas quarry exposes ca. 160 m of marls and marly limestones and extends from the middle Coniacian to the middle Santonian. The lower, more marly part is referred to the La Barranca Member of the El Zadorra Formation; the higher part to the Olazagutia Formation.
Primary Markers:
First occurrence of the inoceramid bivalvePlatyceramus undulatoplicatus.
Secondary Markers:
First occurrence of the planktonic foraminiferSigalia carpatica, which is 7 m below the primary marker.
Correlation Events:
Six peaks in the carbon stable isotope curve can be recognized between the Kingsdown Event 17.2 m below and the Bedwell Event 12.35 m above the GSSP.