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GSSP for Hettangian Stage


Definition:

The base of the Hettangian Stage (base of the Jurassic System) is exposed in the Kuhjoch East Section, Karwendel Mountains, Northern Calcareous Alps, Austria. The boundary level is 5.80 m above the base of the Tiefengraben Member of the Kendelbach Formation and corresponds to the first appearance of the ammonite Psiloceras spelae tirolicum.


Location:

The Kuhjoch Section is situated about 25 km north-north-east of Innsbruck and 5 km east-north-east of the village of Hinterriss at a latitude of 47°29'0"N and a longitude of 11°31'50"E.
GSSP for Hettangian Stage


Sedimentology:

The boundary section lies within the Kendlbach Formation. The Kendlbach Formation is divided in the lower 22 m thick terrigeneous Tiefengraben Member and the upper 3 m thick calcareous Breitenberg member.
Grey to brownish marls (up to 13 cm thick) with concretions of pyrite and wormshaped traces constitute the base of the Tiefengraben Member and are overlain by yellowish weathering, partly laminated marls (30 cm thick) passing into reddish, partly laminated, clayey marls approximately 2 m thick. The reddish, clayey marls are known as Schattwald Beds in the Allgäu nappe.
Greyish intercalations characterize the transition to the overlying main part of the Tiefengraben Member, 19 m thick. The marls become more silty above the Schattwald Beds.
The GSSP level is located 3.5m above the Schattwald Beds.


Primary Markers:

The boundary level corresponds with the FAD of the ammonite Psiloceras spelae tirolicum.

Secondary Markers:

Ostracods:
FAD of ostracod Eucytherura n.sp. is near the GSSP
Foraminifers:
The FAD of foraminifer Praegubkinella turgescens is 50 – 60 cm below the GSSP.
Palynomorphs:
The FAD of palynomorph Cerebropollenites thiergartii 3.2 m below the GSSP.

Correlation Events:

Ammonite FAD of Psiloceras spelae tirolicum

Notes on Derivation of Age:

U-Pb age just below proposed GSSP for base-Jurassic in British Columbia

References:

Hillebrandt, A. von, Krystyn, L., Kürschner, W.M., with contributions by Bown, P.R., McRoberts, Ch., Kment, K., Ruhl, M., Simms, M., Tomasovych, A., and Urlichs, M., 2008. A candidate GSSP for the base of the Jurassic in the Northern Calcareous Alps (Kuhjoch section; Karwendel Mountains, Tyrol, Austria). International Subcommission on Jurassic Stratigraphy, Triassic/Jurassic BoundaryWorking Group Ballot 2008, 44.


Hillebrandt, A. von, Krystyn, L., Kürschner, W.M., Bonis, N.R., Ruhl. M., Richoz, S., Schobben, M.A.N., Urlichs, M., Bown, P.R., Kment, K., McRoberts, C.A., Simms, M., Tomasovych, A., 2013. The Global Stratotype Sections and Point (GSSP) for the base of the Jurassic System at Kuhjoch (Karwendel Mountains, Northern Calcareous Alps , Tyrol, Austria). Episodes 36/3, p.162-198, 2013.



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