Aretz et al_2011.pdf - ORBi - Université de Liège

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Kölner Forum Geol. Paläont., 19 (2011)
M. ARETZ, S. DELCULÉE, J. DENAYER & E. POTY (Eds.)
Abstracts, 11th Symposium on Fossil Cnidaria and Sponges, Liège, August 19-29, 2011
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The Upper Jurassic coral community of the Ellipsactinia Limestones reef
complex (Central Apennines, Italy)
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Cristiano RICCI 1 , Bernard LATHUILIÈRE 2 & Giovanni RUSCIADELLI 1
1 Dipartimento di Geotecnologie, Università “G. d’Annunzio”, Chieti, Italy;
c.ricci@unich.it; grusciadelli@unich.it.
2 UMR CNRS 7566, Géologie et Gestion des Ressources Minérales et Energétiques (G2R), Université de
Nancy I, France; bernard.lathuiliere@g2r.uhp-nancy.fr.
In the history of the Earth, the Late Jurassic is generally known to be a time when reefal activity was
widely expanded (KIESSLING 2002; WOOD 1999), with a greater diffusion and differentiation of reefs in the
Tethys realm (e.g. CECCA et al. 2005; LEINFELDER et al. 2002). On the basis of their biotic composition and
their paleogeographic setting, Upper Jurassic reefs have been subdivided into distinctive types of reef
complexes (CREVELLO & HARRIS 1984; LEINFELDER et al. 2002; SCOTT 1988). Mixed coral- stromatoporoid
reefs dominate Isolated Intra-Tethys platform margins, whereas in the North Tethys/North Atlantic reefs,
corals largely out-competed stromatoporoids (see LEINFELDER et al. 2002; 2005 for a review). Unlike other
Upper Jurassic reefs, which have been the subject of numerous and detailed studies, Intra-Tethyan reefs
have received little attention. Studies are in large part descriptive and only rarely contain sedimentological,
taxonomical or paleoecological contributions. Recently RUSCIADELLI et al. (2011) have proposed an
innovative zonation model for Upper Jurassic Intra-Tethys reef complexes. This model is based on excellent
exposures in central Apennines (Italy) that allow the reconstruction of the reef profile across the Upper
Jurassic platform margin. The zonation is revealed by the distribution of main reef builders (corals and
calcified demosponges) and sedimentological characteristics along the reef complex (Fig. 1).
Fig. 1: Depositional model and reef zonation of the studied portion of the Upper Jurassic reef complex. The figure
shows the distribution of the main reef components in relation to the reconstructed depositional profile. Reef zones
correspond to different sub-environments defined by distinct abiotic characteristics, distinctive biotic assemblages
and characteristic hydrodynamic regime. (modified after RUSCIADELLI et al. 2011).