A revised stratigraphic framework for the Messinian succession of Cyprus is proposed demonstrating that the three-stage model for the Messinian salinity crisis recently established for the Western Mediterranean also applies to the Eastern Mediterranean, at least for its marginal basins. This analysis is based on a multidisciplinary study of the Messinian evaporites and associated deposits exposed in the Polemi, Pissouri, Maroni/Psematismenos and Mesaoria basins. Here, we document for the first time that the base of the unit usually referred to the 'Lower Evaporites' in Cyprus does not actually correspond to the onset of the Messinian salinity crisis. The basal surface of this unit rather corresponds to a regional-scale unconformity, locally associated with an angular discordance, and is related to the erosion and resedimentation of primary evaporites deposited during the first stage of the Messinian salinity crisis. This evidence suggests that the 'Lower Evaporites' of the southern basins of Cyprus actually belong to the second stage of the Messinian salinity crisis; they can be thus ascribed to the Resedimented Lower Gypsum unit that was deposited between 5.6 and 5.5 Ma and is possibly coeval to the halite deposited in the northern Mesaoria basin. Primary, in situ evaporites of the first stage of the Messinian salinity crisis were not preserved in Cyprus basins. Conversely, shallow-water primary evaporites deposited during the third stage of the Messinian salinity crisis are well preserved; these deposits can be regarded as the equivalent of the Upper Gypsum of Sicily. Our study documents that the Messinian stratigraphy shows many similarities between the Western and Eastern Mediterranean marginal basins, implying a common and likely coeval development of the Messinian salinity crisis. This could be reflected also in intermediate and deep-water basins; we infer that the Lower Evaporites seismic unit in the deep Eastern Mediterranean basins could well be mainly composed of clastic evaporites and that its base could correspond to the Messinian erosional surface

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[1] A high-resolution pelagic bulk carbonate stable isotope record from a central Tethyan lower Cretaceous composite section is presented. Three well-exposed sedimentary sequences (Chiaserna Monte Acuto, Bosso, and Gorgo a Cerbara sections, central Italy) cropping out throughout the Maiolica Formation were correlated by a detailed magnetostratigraphy, lithostratigraphy, and calcareous plankton biostratigraphy in order to reconstruct a continuous composite record from the middle Berriasian to the lower Aptian. The integrated stratigraphy of the three sequences provided an accurate time framework for the new high-resolution C isotope curve which is presented in this study. The composite d 13 C signal, recorded in the depth domain, was analyzed by combined Lomb-Scargle periodogram and weighted wavelet Z transform (WWZ) -weighted wavelet amplitudes (WWA) Foster wavelet spectral methodologies, both appropriate for unevenly sampled curves. These tools allowed us to unravel the main frequencies modulating the record and their hypothetical shift in depth, respectively. The longterm, $400,000 and $2,400,000 years, eccentricity cycles were consistently recorded throughout all the composite record. Once band-pass filtered in these two periodicity bands and compared to the lithologic pattern cycles identified throughout the composite sequence, the d 13 C signal was used as a valuable proxy record for a reliable construction of an orbital tuning of the early Cretaceous. An estimated age for all the different stratigraphic events recognized throughout the composite record was reported. In particular, the reestimated ages of the paleomagnetic chrons, documented in the upper part of the record, show differences with those reported by Gradstein et al. (2004) up to $2 m.y. The Valanginian carbon shift, present in the middle part of the composite sequence was estimated to be $2.3 m.y. long. The good agreement between the estimated age of the base of this positive carbon isotope excursion ($136.34 m.y.) and the predominant volcanic phase associated to the Paranà-Etendeka large igneous province intrusion confirmed a possible cause-effect link between the two events.

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At the end of the Miocene, water exchange between the Mediterranean Sea and the world ocean was severely reduced, leading to deposition of huge volumes of evaporites during the Messinian salinity crisis (MSC). The onset of this event has been precisely dated at 5.971 Ma by means of magneto-, bio-and cyclostratigraphic tools, but clear paleobiological proxies for its recognition are so far missing, especially in those basins in which evaporite deposition is delayed. The disappearence of calcareous microfossils was the only paleobiological signal used to approximate the beginning of the crisis, but recently calcareous plankton has been recorded above the onset in several sections. Calcareous nannofossil and planktonic foraminifer data from the Piedmont Basin indicate that the cycle recording the beginning of the crisis is characterized by a peculiar succession of bioevents. These bioevents are (i) a calcareous nannofossil Sphenolithus abies abundance peak, followed or accompanied by minor peaks of Helicosphaera carteri, Umbilicosphara rotula and Rhabdosphaera procera, and (ii) the planktonic foraminifer Globorotalia scitula and G. suterae influx. The same sequence of bioevents has been recorded in sections from the Eastern and Central Mediterranean (Pissouri and Tokhni sections in Cyprus; Fanantello section in the Apennines) within the same age range. We thus propose that the S. abies and U. rotula peaks (often accompanied by minor peaks of H. carteri and R. procera) provide a reliable tool for the identification of the onset of the MSC independently from the occurrence of evaporites. This is particularly useful when studying successions deposited in intermediate-and deep-water basins, where evaporites are absent or their deposition is delayed. Our findings can potentially provide a reliable proxy for the identification of the MSC onset in deep-sea cores.

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The thick gypsum deposits formed in the Mediterranean Basin during the Messinian salinity crisis incorporate dense mazes of filamentous fossils, which were interpreted as algae or cyanobacteria, thus pointing to a shallow-marine subtidal or intertidal environment. The data presented here reveal that these filaments represent remains of colorless, vacuolated sulfide-oxidizing bacteria. This interpretation is supported by the presence of small crystal aggregates of iron sulfide (pyrite) and associated polysulfide within the filamentous fossils. Pyrite and polysulfide are considered to result from early diagenetic transformation of original zero-valent sulfur globules stored within the cells, which is a clade-diagnostic feature of living and degraded sulfur bacteria. In addition to filamentous fossils, the studied gypsum crystals contain remains of euryhaline and stenohaline diatoms and clay-rich aggregates interpreted as alteration products of marine snow floccules. This peculiar fossil assemblage reflects conditions of increased productivity in the water column, triggered by high fluxes of nutrients into the basin during phases of enhanced riverine runoff and freshwater discharge. This study confirms that gypsum evaporites have great potential to preserve the early stages of the taphonomic alteration of bacterial cells, shedding light on the paleoecology of ancient hypersaline environments.

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