Conference:
Abstracts book of 13th Congress RCMNS, 2-6 September 2009, Naples, Italy “Earth System Evolution and the Mediterranean Area”, 2-6 September 2009, Naples, Italy, Acta Naturalia de “L’Ateneo Parmense”, Parma: 45 (1) p.334.
Authors:
Georges Clauzon, Jean-Pierre Suc, Mihaela Carmen Melinte-Dobrinescu, Gwenaël Jouannic, Laurent Jolivet, Jean-Loup Rubino, Speranta-Maria Popescu, Christian Gorini, François Bache, Ferran Estrada.
Abstract:
The Andalusian Sorbas and Vera basins have been intensively studied and are described in a large number of papers. However, very few satisfying interpretations have been published for the Sorbas Basin probably because of a lack of precise datation of the post-evaporitic deposits (Montenat & Ott d’Estevou, 1977; Martín-Suárez et al., 2000) and some confusion about the identification of the Messinian Erosional Surface (Gautier et al., 1994; Riding et al., 1998; Fortuin et al., 2000). After an intensive field investigation and many datations using nannoplankton, we propose a new understanding of the Sorbas Basin (Fig. 1). The gypsum deposits (Yesares Member) represent the minor sea-level fall of the first step of the Messinian Salinity Crisis (Clauzon et al., 1996). The Yesares Member and the carbonated term of the Sorbas Member are impacted by a strong widespread subaerial erosion (including the karst of the “Cuevas de Sorbas”) as also the peripheral massive coral reefs. The nested clayey sediments (including those infilling the karstic cavities) have provided everywhere Ceratolithus acutus and have hence an early Zanclean age. These clayey sediments are the bottomset beds of three coalescent Gilbert-type fan deltas (Cariatiz, Gochar, Moras), the coarse foreset and topset beds of which are generally placed within the so-called “Terminal Complex”. Deposits of the Zorreras Member belong to the topset beds of these Gilbert-type fan deltas and are also Zanclean in age. More than ever, the Sorbas Basin must be considered as the Mediterranean reference basin of the marginal response to the two steps of the Messinian Salinity Crisis (Clauzon et al., 1996; CIESM, 2007). The Vera Basin benefits from more complete chronologic information in spite of some confusion (Benson & Rakic-El Bied, 1991; Fortuin et al., 1995). In many places (Garrucha, Cortijo de San Antonio, etc.), a coarse detritic formation (including many reworked gypsum blocks) infills the Messinian canyon and is overlain by largely developed coalescent Gilbert type fan deltas, the bottomset beds of which provide everywhere microfossils of the early Zanclean. Relationships with the offshore seismic profiles are established.