NEW BIOSTRATIGRAPHIC AND LITHOLOGICAL DATA ON THE NEOGENE AND QUATERNARY OF THE LIVORNO AREA (TUSCANY, CENTRAL ITALY)

Lithofacies analyses and datings using calcareous nannofossils, proved to be an excellent opportunity to understand the palaeoenvironmental evolution of the area of the Tuscan coast, washed up by the Ligurian Sea. A multidisciplinary approach, through lithological and micropaleontological data, collected from fifteen boreholes and one outcrop, permitted the characterization of ten stratigraphic units in the subsurface of the Livorno area. The correlations of these units depicted a stratigraphic architecture chronologically constrained. This study detected early Pliocene (Zanclean) and early Pleistocene (Gelasian) marine deposits, referable to the outer neritic zone that were dated to the calcareous nannofossil biozones MNN13, MNN14-15 and MNN18. In addition, early Pleistocene (Calabrian) marine deposits, dated to the calcareous nannofossil biozones MNN19b, MNN19d, MNN19e, which may be attributed to different bathymetric depths on the basis of benthic foraminifers and ostracods, highlighted sea level changes. Finally, the areal distribution and the stratigraphic architecture of these units permitted the recognition and the better constraining of the sedimentary dynamics impacted by major eustatic and tectonic changes. &nbsp

Updated picture of the Ligurian and Sub-Ligurian units in the Mt. Amiata area (Tuscany, Italy): Elements for their correlation in the framework of the Northern Apennines

The Mt. Amiata region (Southern Tuscany, Italy) represents the southernmost area of the Northern Apennines in which different lithologies belonging to the Ligurian and Sub-Ligurian units crop out widely. This paper provides an update on the stratigraphic, paleontological and structural features of the Ligurian and Sub-Ligurian units in the Mt. Amiata area by integrating new data from the Regional Geological Mapping project with those available from the existing literature. In the study area, the Sub-Ligurian units are represented by the Canetolo unit, which comprises the middle Eocene (Zone NP15) Argille e Calcari and Vico Fms showing heteropic relationships. The Ligurian units are represented by the Ophiolitic and Santa Fiora units. The Ophiolitic unit consists mainly of Early Cretaceous Palombini Shale associated with scattered Middle-Late Jurassic ophiolites. The age of the Palombini Shale spans from late Hauterivian-Barremian Zone CC5 to Aptian Zone CC7 of SISSINGH (1977). The Ophiolitic unit overlies the Santa Fiora unit consisting of the Pietraforte Fm and Varicoloured Shales topped by the Santa Fiora Fm. The Pietraforte Fm shows heteropic relationships with the Varicoloured Shale, and both formations can be referred to the ?Aptian to middle Coniacian. The age of the Santa Fiora Fm seems to span from the late Coniacian-early Santonian (Zone CC14) to middle-late Campanian (Zones CC21-CC22). Structural analyses indicate that all the Ligurian and Sub-Ligurian units experienced complex polyphase deformation through several folding phases during the closure of the Ligurian-Piemontese oceanic basin and the subsequent continental collision, which began in the middle Eocene. The Ligurian and Sub-Ligurian units now come into contact through low-angle shear zones developed during the last deformation phase identified in these units, i.e. middle Miocene extensional tectonics. This tectonic phase produced strong delamination through low-angle faults with staircase geometry, so that not only several stratigraphic levels but also entire tectonic units were omitted. Despite the extensional tectonics, the collected stratigraphic and structural data suggest a correlation between the Ligurian and Sub-Ligurian units of the Mt. Amiata area and the units cropping out in Southern Tuscany and the Ligurian-Emilian Apennines

MIDDLE PLIOCENE CETACEANS FROM MONTE VOLTRAIO (TUSCANY, ITALY). BIOSTRATIGRAPHICAL, PALEOECOLOGICAL AND PALEOCLIMATIC OBSERVATIONS

The historic collection of fossil odontocetes (Cetacea) from Monte Voltraio, near Volterra (Tuscany, Italy) has been examined and lithostratigraphical and biostratigraphical investigations on the find locality have been carried out. The Monte Voltraio outcrop is referred to the Middle Pliocene, in particular to Globorotalia aemiliana and Discoaster tamalis zones. The odontocete remains are assigned to the families Kogiidae (Kogia pusilla) and Delphinidae (Globicephala? etruriae and two indeterminate specimens which might belong to Hemisyntrachelus and Stenella giulii). The Middle Pliocene cetacean fauna from the Mediterranean basin (Monte Voltraio and Rio Stramonte associations) includes extinct taxa or extant taxa no longer represented in this basin. The disappearance of these taxa may be linked with the Pliocene and/or Quaternary climatic deteriorations (e.g. the climatic crisis at about 2.6-2.4 MA).&nbsp

Lower Oligocene thrust-system in the epi-Ligurian succession: evidence from the Enza Valley (northern Apennines, Italy)

Abstract Within the lower part (Upper Eocene-Oligocene) of the epi-Ligurian succession, outcropping in the Emilian side of the northern Apennines (Enza Valley), duplications by thrust tectonics were recognized through the systematic integration of field geology with calcareous nannofossil biostratigraphy. This thrust system, derived from the overthrusting of two thrust-sheets over a footwall, is unconformably overlain by a Rupelian succession. The thrust structure of the Enza Valley, affected by a subsequent wide overturned syncline together vith the unconformable succession, shows a remarkable Lower Oligocene contractional tectonics, previously not recognized in the northern Apennines. The comparison of this thrust system with other outcropping areas of the epi-Ligurian succession makes probable the wide-spread occurrence of the Lower Oligocene tectonics in the uppermost structural levels of the chain (epi-Ligurian domain). In a regional tectonic framework, the Rupelian thrust tectonics affecting the epi-Ligurian succession can be related to the Lower Oligocene closure of the innermost portion of the Subligurian basin (Aveto-Petrignacola Formation) due to the NE-verging overthrusting of the External Ligurian Units. In this context the unconformable succession of the Enza Valley seems correlable with the basal portion of the Subligurian Eratica Sandstone (Rupelian-Chattian) which unconformably overlies a deformed substratum (Mesoalpine Phase)

Redefinition of the Ligurian Units at the Alps–Apennines junction (NW Italy) and their role in the evolution of the Ligurian accretionary wedge: constraints from mélanges and broken formations

We document that the undifferentiated chaotic Ligurian Units of the Monferrato–Torino Hill sector (MO-TH) at the Alps–Apennines junction consist of three different units that are comparable with the Cassio, Caio and Sporno Units of the External Ligurian Units of the Northern Apennines. Their internal stratigraphy reflects the character of units deposited in an ocean–continent transition (OCT) zone between the northwestern termination of the Ligurian–Piedmont oceanic basin and the thinned passive margin of Adria microcontinent. The inherited wedge-shaped architecture of this OCT, which gradually closed toward the north in the present-day Canavese Zone, controlled the Late Cretaceous–early Eocene flysch deposition at the trench of the External Ligurian accretionary wedge during the oblique subduction. This favoured the formation of an accretionary wedge increasing in thickness and elevation toward the SE, from the MO-TH to the Emilia Northern Apennines. Our results therefore provide significant information on both the palaeogeographical reconstruction of the northwestern termination of the Ligurian–Piedmont oceanic basin and the role played by inherited along-strike variations (stratigraphy, structural architecture and morphology) of OCT zones in controlling subduction–accretionary processes

Fossilwhale barnacles fromthe lower pleistocene of sicily shed light on the coevalmediterranean cetacean fauna

We report on three shells of whale barnacle (Cirripedia: Coronulidae) collected from Pleistocene shallow-marine deposits exposed at Cinisi (northwestern Sicily, southern Italy). These specimens are identified as belonging to the extinct species Coronula bifida BRONN, 1831. Calcareous nannoplankton analysis of the sediment hosting the coronulid remains places the time of deposition between 1.93 and 1.71 Ma (i.e., at the Gelasian-Calabrian transition), an interval during which another deposit rich in whale barnacles exposed in southeastern Apulia (southern Italy) formed. Since Coronula LAMARCK, 1802, is currently found inhabiting the skin of humpback whales [Cetacea: Balaenopteridae: Megaptera novaeangliae (BOROWSKI, 1781)], and considering that the detachment of extant coronulids from their hosts’ skin has been mainly observed in occurrence of cetacean breeding/calving areas, the material here studied supports the existence of a baleen whale migration route between the central Mediterranean Sea (the putative reproductive ground) and the North Atlantic (the putative feeding ground) around 1.8 Ma, when several portions of present-day southern Italy were still submerged. The early Pleistocene utilization of the epeiric seas of southern Italy as breeding/calving areas by migrating mysticetes appears to be linked to the severe climatic degradation that has been recognized at the Gelasian-Calabrian transition and that is marked in the fossil record of the Mediterranean Basin by the appearance of “northern guests” such as Arctica islandica (LINNAEUS, 1767) (Bivalvia: Veneroida). The subsequent abandonment of the Mediterranean Sea by most species of mysticetes is likely to have resulted from the progressive emergence of shallow-water coastal environments that occurred in Calabrian and Middle Pleistocene times

The Arkot Dağ Mélange Central Turkey: evidences for the geodynamic evolution of the Intra-Pontide suture zone.

The geological setting of Turkey can be described as an assemblage of continental terranes separated by ophiolite-bearing suture zones that mark the areas where the PaleoTethyan and NeoTehyan oceanic basins were destroyed. In northern Turkey, one of the most important suture zones is represented by the Intra-Pontide one consisting of an east-west trending belt of deformed and/or metamorphic units located at the boundary between the Istanbul-Zonguldak terrane to the north and the Sakarya terrane to the south. These units can be regarded as issued from the Intra-Pontide domain, whose geodynamic history is still a matter of debate. Along the Akpinar-Araç-Bayramoren geotraverse, located in central Turkey, an ophiolite-bearing mélange, known as the Arkot Dağ Mélange, is well-exposed along the Intra-Pontide suture zone. The Arkot Dağ Mélange can be described as an Upper Santonian chaotic sedimentary deposit consisting of an up to 1000-m-thick succession of slide-blocks of different sizes and lithologies enclosed in a sedimentary matrix consisting of shales, coarse-grained arenites, pebbly mudstones and pebbly sandstones. The slide-blocks, from a few meters to hectometers in size, are represented by metamorphic rocks (mainly micaschists and gneisses), by ophiolites (peridotites, gabbros, IAT and BAB basalts and cherts) and by sedimentary rocks (cherts, neritic and pelagic limestone, marly limestone and ophiolite-bearing turbidites). The youngest age among the slide- blocks has been provided by the ophiolite-bearing turbidites where a late Coniacian nannofossil assemblage has been found. The cherts have provided a wide range of ages from the Middle Triassic to Late Cretaceous, whereas the fossils found in the limestone indicate Late Jurassic to Early Cretaceous ages. The matrix of the Arkot Dağ Mélange, even if unaffected by metamorphism, shows deformations represented by multiple meters-thick cataclastic shear zones at the boundaries of the mélange slices or inside them. According to its features, the source area of the Arkot Dağ Mélange was most likely a stack of continental and oceanic thrust sheets emplaced in the Late Cretaceous onto a continental margin. The data collected from the different slide-blocks suggest that the Intra-Pontide domain was characterised by an oceanic basin that opened at the latest in the Early Jurassic. The opening of the Intra-Pontide oceanic basin was followed by the development of a subduction zone with a subsequent opening of suprasubduction oceanic basin in the Middle Jurassic – Early Cretaceous. The convergence in this suprasubduction oceanic basin started at the Early/Late Cretaceous boundary by an obduction process, whereas its final closure can be regarded as Late Paleocene

Multiple Orbitoides d’Orbigny lineages in the Maastrichtian? Data from the Central Sakarya Basin (Turkey) and Arabian Platform successions (Southeastern Turkey and Oman)

The standard reconstruction of species of Orbitoides d'Orbigny into a single lineage during the late Santonian to the end of the Maastrichtian is based upon morphometric data from Western Europe. An irreversible increase in the size of the embryonic apparatus, and the formation of a greater number of epi-embryonic chamberlets (EPC) with time, is regarded as the main evolutionary trends used in species discrimination. However, data from Maastrichtian Orbitoides assemblages from Central Turkey and the Arabian Platform margin (Southeastern Turkey and Oman) are not consistent with this record. The Maastrichtian Besni Formation of the Arabian Platform margin in Southeastern Turkey yields invariably biconvex specimens, with small, tri- to quadrilocular embryons and a small number of EPC, comparable to late Campanian Orbitoides medius (d'Archiac). The upper Maastrichtian Tarakli Formation from the Sakarya Basin of Central Turkey contains two distinct, yet closely associated forms of Orbitoides, easily differentiated by both external and internal features. Flat to biconcave specimens possess a small, tri- to quadrilocular embryonic apparatus of Orbitoides medius-type and a small number of EPC, whereas biconvex specimens possess a large, predominantly bilocular embryonic apparatus, and were assigned to Orbitoides ex. interc. gruenbachensis Papp-apiculatus Schlumberger based on morphometry. The flat to biconcave specimens belong to a long overlooked species Orbitoides pamiri Meric, originally described from the late Maastrichtian of the Tauride Mountains in SW Turkey. This species is herein interpreted to be an offshoot from the main Orbitoides lineage during the Maastrichtian, as are forms that we term Orbitoides 'medius', since they recall this species, yet are younger than normal occurrence with the accepted morphometrically defined lineage. The consistent correlation between the external and internal test features in O. pamiri implies that the shape of the test is not an ecophenotypic variation, but appears to be biologically controlled. We, therefore, postulate that more than one lineage of Orbitoides exists during the Maastrichtian, with a lineage that includes O. 'medius' and O. pamiri displaying retrograde evolutionary features