13th Congress of the Regional Committee on Mediterranean Neogene Stratigraphy (RCMNS), Naples, Italy: Acta Naturalia de L’Ateneo Parmense, 2009
In the Cingoli area (Marche, northern Apennines), the well-known uppermost Messinian Maccarone se... more In the Cingoli area (Marche, northern Apennines), the well-known uppermost Messinian Maccarone section crops out in a badlands area. The section mainly consists of marls with thin intercalations of sandstone and carbonate. A well-exposed disconformity surface separates the postevaporitic Messinian deposits in a lower portion (p-ev1, San Donato Fm pp) and an upper portion (p-ev2, San Donato Fm pp and Colombacci Fm). A volcaniclastic layer and three organic-matterrich horizons with ankerite beds characterise the lower ...
The Miocene-Pliocene boundary in the Northern Apennine was the object of several studies prior to... more The Miocene-Pliocene boundary in the Northern Apennine was the object of several studies prior to the definition of the GSSP of the Zanclean stage in the Eraclea Minoa section (Sicily, Italy). This definition came at the end of the '90s, after an accurate and Mediterranean wide high resolution biostratigraphic study of the basal Pliocene deposits. Since then calcareous plankton biostratigraphy allows to correlate the very base of the Zanclean through the occurrence of two consecutive sinistrally coiled Neogloboquadrina acostaensis influxes, respectively placed within the 1st/2nd cycle and the 2nd/3rd cycle from the base astronomically dated at 5.33 Ma (insolation peak 510). Besides these bioevents, the classical Spheroidinellopsis spp. acme interval, the base of subchron Thvera and the cyclic signal of both biota and lithology help recognize the base of the Zanclean stage. Several sections and boreholes were studied in an east (Marche region) to west (Emilia region) transect along the Northern Apennine. Despite different sampling resolution, the two N. acostaensis sinistral influxes were recognized in each sites except the Montepetra borehole were the definition of the Zanclean base was achieved through cyclostratigraphic features. Some nannofossil bioevents, such as the drop of abundance of D. variabilis and the beginning of a paracme interval of R. pseudoumbilicus, revealed to be useful for a better constraining of the basal Zanclean. Thus the sedimentary succession across the Messinian -Zanclean boundary was recognized to be continuous and the base of the Zanclean stage coeval to its GSSP at Eraclea Minoa, thus dated at 5.33 Ma. This demonstrates that the Zanclean restoration of marine condition that ended the Messinian salinity crisis was a synchronous event, geologically speaking within the present resolution power, throughout the entire Mediterranea region.
Evidence of Clastic Evaporites In the Canyons of the Levant Basin (Israel): Implications For the Messinian Salinity Crisis. JOURNAL OF SEDIMENTARY RESEARCH, vol. 83, p. 942-954
A shallow water record of the onset of the Messinian salinity crisis in the Adriatic foredeep (Legnagnone section, Northern Apennines). PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY, vol. 386, p. 145-164,
Dense shelf water cascading and Messinian canyons: a new scenario for the Mediterranean salinity crisis. AMERICAN JOURNAL OF SCIENCE, vol. 314, p. 751-784
The Alba succession (Tertiary Piedmont Basin, NW Italy) preserves the northernmost record of the ... more The Alba succession (Tertiary Piedmont Basin, NW Italy) preserves the northernmost record of the Messinian salinity crisis (MSC) and was deposited on the southern margin of a wide wedge-top basin, related to the involvement of the Piedmont Basin in the Apennine compressional tectonics. Pre-MSC sediments consist of a cyclic succession of marine euxinic shales and calcareous marls, deposited under the influence of precession-modulated climate changes, and document the progressive restriction of the basin prior to the onset of the MSC. They are followed by the Primary Lower Gypsum unit (PLG), deposited during the first MSC stage (from 5.96 to 5.60 Ma). These sediments show a clear precession-related cyclic stacking pattern and record the lateral transition from a shallow water marginal setting in the SW to a deeper one in the NE. In marginal settings, six PLG cycles are recognised, truncated by an erosional unconformity placed at the base of the post-evaporitic sediments. The lowermost five cycles are composed of massive and banded selenite beds separated by thin shale intervals. A sharp change, evidenced by the appearance of the branching selenite facies, is recorded by the 6th gypsum bed that represents a distinctive marker bed, here called Sturani key-bed, that can be mapped throughout the study area. Basinward, the lower PLG cycles are transitional to decimetre-thick carbonate-rich layers interbedded to euxinic shales, that are overlain by the Sturani key-bed. Above the marker bed, other seven PLG cycles are present. The gypsum beds form thinner bodies compared to the Sturani key-bed and are characterised by a greater amount of fine-grained terrigenous fraction, suggesting an increase of continental runoff related, in turn, to humid climate conditions at the end of the first MSC stage. PLG cycles are followed by slumped mudstones and clastic gypsum beds that correspond to the resedimented and chaotic facies (Resedimented Lower Gypsum), deposited in the Mediterranean basins during the second MSC stage (from 5.60 to 5.55 Ma). They are in turn overlain by continental and brackish water facies with Lago Mare fossil assemblages, recording the final stage of the MSC. The Messinian succession of Alba provides the opportunity to reconstruct the lateral facies transition between marginal and distal settings and to shed new light on the deep water MSC sedimentary record. Moreover, the appearance of the branching selenite facies from the 6th PLG cycle upward provides a tool for properly placing the Piedmont record in the MSC chronostratigraphic framework, allowing us to investigate the influence of climate gradients on the sedimentary response to the Mediterranean salinity crisis.
A possible deep-water non-evaporitic unit equivalent of the Messinian Lower Evaporites has been r... more A possible deep-water non-evaporitic unit equivalent of the Messinian Lower Evaporites has been recognised in the Northern Apennine foredeep. This unit, whose existence is implicitly admitted in the two-step model of the Mediterranean Messinian salinity crisis is documented here for the first time; it occurs throughout the Apennine foredeep basin below a thick horizon of resedimented gypsum deposits, usually ascribed to the Lower Evaporites. Actually, the Lower Evaporites of the Apennine foredeep basin include both shallow-water, in situ precipitated facies and deep-water, resedimented facies deposited in distinct depocenters. The usually envisaged coeval nature of the two deposits has been recently challenged in several works based on a) physical-stratigraphic considerations about the downbasin correlation of the Messinian erosional surface cutting on top the in situ evaporites with the sharp base of the resedimented evaporites unit and b) the common occurrence of a barren unit below the resedimented evaporites which has no obvious equivalents in pre-evaporitic successions underlying the in situ precipitated evaporites.
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Papers by Rocco Gennari