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Episodes 2001; 24(3): 166-175

Published online September 1, 2001


Copyright © International Union of Geological Sciences.

The Global Boundary Stratotype Section and Point (GSSP) of the Toarcian-Aalenian Boundary (Lower-Middle Jurassic)

S. Cresta1, A. Goy2, S. Ureta2, C. Arias2, E. Barrón2, J. Bernad2, M. L. Canales2, F. García-Joral2, E. García-Romero2, P. R. Gialanella2, J. J. Gómez2, J. A. González2, C. Herrero2, G. Martínez2, M. L. Osete2, N. Perilli2, J. J. Villalaín2

1Agenzia regionale Parchi del Lazio, Via Indonesia 33, 00144 Roma, Italy.
2Departamento de Paleontologia, Universidal Complutense de Madrid, 28048 Madrid, Spain.

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.


The Global Boundary Stratotype Section and Point (GSSP) for the Aalenian Stage, formally defined at the base of bed FZ107 in the Fuentelsaz section, Castilian Branch of the Iberian Range (Spain), has been ratified by the IUGS. Multidisciplinary biostratigraphical data, based on ammonites, brachiopods, ostracods, bivalves, foraminifera, calcareous nannofossils assemblages and palynomorphs, assure worldwide correlations; magnetostratigraphic data increase this correlation power. The position of the boundary coincides with the first occurrence of the ammonite assemblage characterized by Leioceras opalinum and Leioceras lineatum and corresponds with a normal polarity interval correlated with the up-to-date Jurassic magnetic polarity time scale (Gradstein and others, 1994; Ogg, 1995).