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GSSP for Coniacian Stage

Definition:

The base of the Coniacian Stage is defined at the base of Bed 46 of the Salzgitter-Salder Section in northern Germany. The GSSP coincides with the first occurrence of the inoceramid bivalve Cremnoceramus deformis erectus (Meek) and is complimented by the Navigation carbon isotope event.

Location:

The Salzgitter-Salder Quarry Section is located in the Lower Saxony Basin of Germany. The GSSP section is part of the UNESCO Geopark "Harz-Braunschweiger Land- Ostfalen". The GSSP is located at a latitude of 52.1243°N and a longitude of 10.3295°E. 		GSSP for Coniacian Stage


Sedimentology:

The Turonian - Coniacian Boundary lies in a succession of well-bedded carbonates of the Erwitte Formation. It is composed of uniform limestone, marly limestone and marl alternations. The GSSP lies in the upper part of the Grauweisse Wechselfolge Member of the Erwitte Formation just 8 m below the Upper Limestone Member.


Primary Markers:

The GSSP coincides with the first occurrence of the inoceramid bivalve Cremnoceramus deformis erectus.

Secondary Markers:

Stable Isotopes:
The Coniacian GSSP is bracketed by the negative Navigation Carbon Isotope Event, which extends from Bed 42 (option 1) or Bed 39 (option 2) to the middle of Bed 46 in the Salzgitter Section.

Correlation Events:

Inoceramid bivalve FAD Cremnoceramus deformis erectus

Other Locations around the World:

Auxiliary sections are in: Słupia Nadbrzeźna, central Poland; Střeleč, Czech Republic; El Rosario, and NE Mexico.

Notes on Derivation of Age:

Spline fit of Ar-Ar ages and ammonite zones.

Additional Comments:

Markers across the Turonian - Coniacian Boundary:
In stratigraphic order from oldest (Bed 35b) to youngest (Bed 73):

Beds Markers
Beds 35b - 36 Two positive carbon isotope peaks, referred to collectively as the "i5" Event.
Beds 39b - 45b A negative δ13C excursion, the Navigation Carbon Isotope Event (CIE) Option 2.
Bed 39b The lower acme occurrence of the bivalve genus Didymotis which is the Didymotis I Event
Bed 41 The lowest occurrence (LO) of ammonite Forresteria (Harleites) petrocoriensis (projected from the Słupia Nadbrzeźna auxiliary section).
Bed 42 LO of planktonic foraminifer Dicarinella concavata (projected from the El Rosario and Słupia Nadbrzeźna auxiliary section).
Beds 42a - 45b The Navigation Carbon Isotope Event (CIE) (Option 1).
Bed 44 The highest occurrences (HO) of inoceramid Mytiloides herbichi and Mytiloides scupini
Bed 45a LO of inoceramid Cremnoceramus waltersdorfensis waltersdorfensis and the DidymotisII Event.
Bed 46 LO of inoceramidCremnoceramus deformis erectus, the base of the Coniacian Stage. Top of the Navigation Carbon Isotope Event. Highest consistent occurrence (HCO) of dinocyst Cyclonephelium membraniphorum.
Bed 47a The lowest acme occurrence of Cremnoceramus deformis erectus, which is the erectus I Event.
Bed 49a A higher acme occurrence of Cremnoceramus deformis erectus, which is the erectus II Event; the "i6" Event, a positive carbon isotope excursion.
Bed 52b LO of Cremnoceramus waltersdorfensis hannovrensis
Bed 53a The third acme occurrence of Cremnoceramus deformis erectus, which is the erectus III Event.
Bed 55 - 58 The "i7" Event, a positive carbon isotope excursion.
Bed 62 HO of calc. nannofossil Helicolithus turonicus.
Beds 69 - 70 The "i8" Event, a positive carbon isotope excursion.
Bed 73 LO of Cremnoceramus crassus inconstans.


References:

Walaszcyk, I., Čech, S., Crampton, J.S., Dubicka, Z., Ifrim, C., Jarvis, I., Kennedy, W.J., Lees, J.A., Lodowiski, D., Pearce, M., Peryt, D., Sageman, B.B., Schiøler, P., Todes, J., Uličný, D., Voigt, S., Wiese, F., with contributions by Linnert, C., Püttmann, T., Toshimitsu, S., 2022. The Global Boundary Stratotype Section and Point (GSSP) for the base of the Coniacian Stage (Salzgitter-Salder, Germany) and its auxiliary sections Słupia Nadbrzeźna, central Poland; Střeleč, Czech Republic; and El Rosario, NE Mexico). Episodes 45/2, p. 181-220.

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