The Global Stratotype Sections and Point (GSSP) for the base of the Jurassic System at Kuhjoch (Karwendel Mountains, Northern Calcareous Alps, Tyrol, Austria)

Abstract

Psiloceras spelae tirolicum. The "Golden Spike" was fixed at Kuhjoch East. The section displays a high and continuous sedimentation rate with a constant facies trend across the boundary level. Other bio-events include the FO of the aragonitic foraminifer Praegubkinella turgescens, and of diverse ostracod species 1.0-3.40 cm below the FO of P. spelae and 3.2 m below P. spelae occurs the continental palynomorph Cerebropollenites thiergartii. Because of the lack of other terrestrial microfloral events this is yet the FO event closest to the FO of P. spelae and allows a correlation with nonmarine sediments. The δ 13 C org record shows a strong initial negative excursion at the boundary between the Kössen and Kendlbach formations, 5.8 m (Kuhjoch W) below the T-J boundary, a shift to more positive δ 13 C org in the Schattwald Beds and a gradual decline to more negative values at the transition of the Schattwald Beds to the proximate Tiefengraben Mb. The stratotype point lies within a zone of smaller negative and positive δ 13 C org peaks, which is superimposed on a longer lasting main negative shift. According to recent investigations, the radiometric age of the T-J boundary is about 201,3 Ma.

An Early Jurassic age for the Puchezh‐Katunki impact structure (Russia) based on 40Ar/39Ar data and palynology

“…However, it should be noted that the latter taxon is also known from stratigraphic sections that encompass the Triassic–Jurassic boundary (Hillebrandt et al. ). Five percent of the total palynofloral assemblage consists of the fresh‐ to brackish‐water alga Botryococcus braunii .…”

“…The presence of Manumia delcourtii and Ischyosporites variegatus indicates an age younger than late Pliensbachian (Batten and Koppelhus 1996). However, it should be noted that the latter taxon is also known from stratigraphic sections that encompass the Triassic-Jurassic boundary (Hillebrandt et al 2013). Five percent of the total palynofloral assemblage consists of the fresh-to brackish-water alga Botryococcus braunii.…”

An ichthyosaur from the UK Triassic–Jurassic boundary: A second specimen of the leptonectid ichthyosaur Wahlisaurus massarae Lomax 2016

“…The base of the Jurassic System is now defined by the first appearance of the ammonite Psiloceras spelae tirolicum , with a Global Boundary Stratotype Section and Point (GSSP) at Kuhjoch in the Northern Calcareous Alps, Tyrol, Austria (Hillebrandt et al, ). Previously, in Britain, the base of the Jurassic had been defined by the first appearance of P. planorbis (Warrington et al, ), with a proposed GSSP at St. Audrie's Bay, Somerset (Warrington, Cope, & Ivimey‐Cook, ).…”

“…The basal ammonite faunas of the Tilmanni Chronozone now known from the GSSP in Austria are not present in Britain and north‐western Europe (Hillebrandt et al, ), meaning that correlation of the Tr–J boundary is problematic. Benson, Evans, and Druckenmiller (), for example, regarded most of the plesiosaurians from the Pre‐planorbis beds of the classic locality of Street, Somerset, as dating from the Tilmanni Chronozone.…”

The best sections method of studying mass extinctions

“…Similarly, a finite number of sections can be identified to study marine extinction events across the Triassic–Jurassic boundary, and these include the sections in Nevada, USA, in British Columbia, Canada, in Peru and in Austria (e. g. von Hillebrandt et al . ). Some of the sections used as GSSP (Global Stratotype Section and Point) locations for chronostratigraphic definition do serve as best sections for studying extinctions, although this may not always be the case (witness, for example, the condensed section at Meishan, China, that is the GSSP for the base of the Triassic, and thus encompasses the end‐Permian mass extinction).…”