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GSSP for Santonian Stage


Definition:

The base of the Santonian Stage is defined at 94.4m in the eastern border of the “Cantera de Margas” quarry, Olazagutia, Navarra, N. Spain. The GSSP coincides with the first occurrence of the inoceramid bivalve Platyceramus undulatoplicatus. The first occurrence of planktonic foraminifer Sigalia carpatica is a secondary marker of the GSSP and occurs 7m below the first occurrence of Platyceramus undulatoplicatus.


Location:

The Olazagutia Section is located in the Basque-Cantabrian Region (Navarra) of northern Spain. The GSSP is located in the eastern border of the “Cantera de Margas” quarry at a latitude of 42°52’5.3”N and a longitude of 2°11’40”W. Lambert coordinates 919, 722; 1:25000 topographic sheet no. 113-4 Olazagutia.
Google Earth coordinates: 42°52’1.77”N, 2°11’45.78”W
GSSP for Santonian Stage


Sedimentology:

The Coniacian – Santonian Boundary lies along the eastern border of the “Cantera de Margas” quarry. The section consists of 160m of marls and marly limestones and encompasses the middle Coniacian through middle Santonian. The GSSP lies in the Olazagutia Formation and is characterized by thin (10-20cm) limestone beds. Thicker-bedded limestones occur higher up in the formation.


Primary Markers:

The GSSP coincides with the first occurrence of the inoceramid bivalve Platyceramus undulatoplicatus

Secondary Markers:

Foraminifera:
Sigalia carpatica occurs 7m below the first occurrence of Platyceramus undulatoplicatus at a 87.4m.
Stable Isotopes:
The Santonian GSSP is bracketed by Peak 3 (3.55m below the GSSP) and the Michel Dean (4.4m above the GSSP) δ13 stable carbon isotope events.

Correlation Events:

Inoceramid bivalve FAD Platyceramus undulatoplicatus

Other Locations around the World:

10 events between the first occurrence of planktonic foraminifer Sigalia carpatica and the first occurrence of inoceramid bivalve Platyceramus cycloides allow correlation to northern and southern temperate provinces.

Notes on Derivation of Age:

Spline fit of Ar-Ar ages and ammonite zones.

Additional Comments:

Markers across the Coniacian – Santonian Boundary:
In stratigraphic order from oldest (1) to youngest (20):

20    LO of Lithastrinus septenarius at the 112.4 m level.
19    Bedwell δ13C stable carbon isotope event at the 106.75 m level.
18    LO of Platyceramus undulatoplicatus at the 105.9 m level.
17    FO of Platyceramus cycloides at the 99.1 m level.
16    Michel Dean δ13C stable carbon isotope event and consistent occurrence of Sigalia carpatica at the 98.6 m level.
15    FO of Neoflabellina praecursor and the first common occurrence of Dicarinella asymetrica at the 95.8 m level.
14    FO of the pill-box-like morphotypes of Globotruncana linneiana at the 94.5 m level.
13    FO of Platyceramus undulatoplicatus at the 94.4 m level.
12    FO of abundant Micula concava at the 93.8 m level.
11    FOs of Neoflabellina gibbera and Lucianorhabdus inflatus, and the FO of abundant holococcoliths at the 92.6 m level.
10    Peak 3 δ13C stable carbon isotope event at the 90.85 m level.
9    FO of Costellagerina pilula at the 90.4 m level.
8    TPeak K2 upper δ13C stable carbon isotope event at the 89.45 m level.
7    Peak K2 lower δ13 stable carbon isotope event at the 87.45 m level.
6    FOs of Sigalia carpatica and Calculites obscurus at the 87.4 m level.
5    FO of Lucianorhabdus cayeuxii at the 81.9 m level.
4    Peak K1 δ13C stable carbon isotope event at the 81.6 m level.
3    FO of Lithastrinus grillii at the 79.9 m level.
2    Kingsdown δ13C stable carbon isotope event at the 77.2 m level.
1    FO of Magadiceramus subquadratus at 64.6 m level.


References:

Lamolda, M.A., Paul, C.R.C., Peryt, D., Pons J.M., 2014. The Global Boundary Stratotype and Section Point (GSSP) for the base of the Santonian Stage, “Cantera de Margas”, Olazagutia, northern Spain. Episodes 37/1, p. 2-13.



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