@article{gledocs_11858_6874,
author = {Wiedmann, J. and Fabricius, F. and Krystyn, L. and Reitner, Joachim and Ulrichs, M.},
title = {Über Umfang und Stellung des Rhaet},
year = {1979},
volume = {8},
number = {2},
pages = {133-152},

abstract = {The duration and position of the Rhaetian Stage are di scussed. With the recognition of Rhabdoceras suessi - up to now the index species of the Upper Norian (Sevatian) - in one of the Alpine type sections of the Rhaetian, this Stage becomes more and more restricted and its separation doubtfu!. Four possibilities for defining the Alpine uppermost Triassic are treated. The authors propose either to redefine the Alpi'ne Rhaetian as the uppermost Substage of thc Norian Stage, thereby replacing the Sevatian (proposal 4), or to include the previous Sevatian into an enlarged Rhaetian Stage (proposal 3). This proposal is favoured by the International Subcommission of Triassic Stratigraphy. Ir is supported by the recent discovery of Choristoceras marshi - index species of the restricted Rhaetian - in the lower part of the Koessen Beds of the Lahnewiesgraben, equivalent to the previous Zone of Rhabdoceras suessi. Ir is moreover supported by the discovery of the immediate ancestor of this species in the upper part of the Middle Norian (Alaunian) of Timor. This makes the suessi Zone synonymous with the marshi Zone, the lower part of wh ich may be treated now as the Subzone of Rhabdoceras suessi. Since no particular ammonite species can be used for defining the upper part, this can be defined only by the exclusive occurrence of Choristoceras marshi without Rhabdoceras messi. As reference section of the redefined Rhaetian Stage the Weißloferbach section near Koessen, Tirol (Austria) is proposed, since it is weil exposed and fossiliferous, bearing cephalopods, bivalves, brachiopods, ostracods, conodonts and other groups. The authors propose moreover to redefine and re-name the "Rhaetian" of the Germanic facies Realm, which can by no means bc correlated with the Alpine Realm. The names "Upper Keuper" or "Rhaetkeuper" may be more adequate. There is, however, some palynological evidence for a correlation of the Germanie Preplanorbis Beds with the Alpine "Schichtenfolge unter Anm. planorbis" in SUESS & MOJSISOVICS (1868), where Choristaceras marshi has disappeared. The occurrence of the first psiloceratid (Neophyllites antecedens) in these beds indicates that they represent the base of the Jur~sic System. Provisionally these Preplanorbis Beds remain included into the Zone of Psiloceras planorbis.},
note = { \url {http://resolver.sub.uni-goettingen.de/purl?gldocs-11858/6874}},
}