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Luisa Sabato
Ruolo
Professore Associato
Organizzazione
Università degli Studi di Bari Aldo Moro
Dipartimento
DIPARTIMENTO DI BIOLOGIA
Area Scientifica
AREA 04 - Scienze della Terra
Settore Scientifico Disciplinare
GEO/02 - Geologia Stratigrafica e Sedimentologica
Settore ERC 1° livello
Non Disponibile
Settore ERC 2° livello
Non Disponibile
Settore ERC 3° livello
Non Disponibile
The first and foremost boundary condition for kinematic reconstructions of the Mediterranean region is the relative motion between Africa and Eurasia, constrained through reconstructions of the Atlantic Ocean. The Adria continental block is in a downgoing plate position relative to the strongly curved central Mediterranean subductionrelated orogens, and forms the foreland of the Apennines, Alps, Dinarides, and Albanides–Hellenides. It is connected to the African plate through the Ionian Basin, likely with Lower Mesozoic oceanic lithosphere. If the relative motion of Adria versus Africa is known, its position relative to Eurasia can be constrained through a plate circuit, thus allowing robust boundary conditions for the reconstruction of the complex kinematic history of the Mediterranean region. Based on kinematic reconstructions for the Neogene motion of Adria versus Africa, as interpreted from the Alps and from Ionian Basin and its surrounding areas, it has been suggested that Adria underwent counterclockwise (ccw) vertical axis rotations ranging from 0 to 20. Here, we provide six new paleomagnetic poles from Adria, derived from the Lower Cretaceous to Upper Miocene carbonatic units of the Apulian peninsula (southern Italy). These, in combination with published poles from the Po Plain (Italy), the Istrian peninsula (Croatia), and the Gargano promontory (Italy), document a post-Eocene 9.8±9.5 counterclockwise vertical axis rotation of Adria. Our results do not show evidence of significant Africa–Adria rotation between the Early Cretaceous and Eocene. Models based on reconstructions of the Alps, invoking 17 ccw rotation, and based on the Ionian Basin, invoking 2 ccw rotation, are both permitted within the documented rotation range, yet are mutually exclusive. This apparent enigma could possibly be solved only if one or more of the following conditions are satisfied: (i) Neogene shortening in the western Alps has been significantly underestimated (by as much as 150 km); (ii) Neogene extension in the Ionian Basin has been significantly underestimated (by as much as 420 km); and/or (iii) a major sinistral strike-slip zone has decoupled northern and southern Adria in Neogene time. Here we present five alternative reconstructions of Adria at 20 Ma, highlighting the kinematic uncertainties, and satisfying the inferred rotation pattern from this study and/or from previously proposed kinematic reconstructions.
The Calanche area extends on the border between the villages of Campomaggiore and Albano di Lucania (PZ) and is characterized by the occurrence of unique stratigraphic and morphological elements that can be considered as geological heritage. In this resort, a stratigraphic unit noted as “argille varicolori” (auctt.) crops out in a suggestive setting represented by badlands varying in colour from grey, to red, to green. The “argille varicolori” sedimentary succession cropping out in this site has taken in the recent years a role of fundamental importance for understanding the regional geology of the southern Apennines and the major Cretaceous climatic changes which affected the history of our Planet and the paleoceanography of the Tethys. In fact, along this sedimentary succession five guide-horizons of particular scientific importance have been recognized. These horizons, some decimeters thick, are characterized by the presence of radiolarites and black shales whose facies and ages allow us to attribute them to an ocean environment deeper than CCD surface, and which experienced relevant conditions of anoxia in certain intervals of time between Aptian and Turonian. Among these horizons, the most representative were correlated to the Selli and Bonarelli horizons, expression of the major Cretaceous Anoxic Oceanic Events occurred on the Earth respectively about 120 and 93 million years ago (OAE1a and OAE2). The recognition of these horizons, as well as the extraordinary landscape of the badlands in which they are found, make unique and valuable the geodiversity of this area and allow us to ask the institutions for the establishment of a protected area. The aim is to preserve the geological heritage, which when equipped with didactic/educational panels, could be transformed into an important page in the evolutionary history of the Earth decipherable not only by a few specialists, but also by a wide and diversifi ed audience. The proximity of this geological site to other places of geological, natural and cultural interests, occurring in the mid valley of the Basento River, enriches the offer of an already existing geoturistic tour and could represent an important opportunity for development of the nearby villages of Campomaggiore and Albano di Lucania, now at the edge of this tour.
I risultati del rilevamento geologico del Foglio 438 “Bari” in scala 1:50.000 effettuato nell’ambito del progetto CARG (Cartografia Geologica) mostrano numerose differenze rispetto a quanto riportato nella Cartografia Ufficiale in scala 1:100.000, che rappresenta tuttora la cartografia di riferimento. Le differenze rilevate, o comunque le ulteriori informazioni ottenute dai nuovi studi, sono risultate molto significative soprattutto in corrispondenza dell’area metropolitana di Bari recentemente soggette ad intensa urbanizzazione ed espansione. Tenuto conto dei tempi necessari per poter divulgare tali dati, si è ritenuto importante, in occasione del Convegno sulla “Geologia urbana di Bari ed area metropolitana”, presentare una carta in scala 1:25.000 del territorio metropolitano barese, dove emergessero tutte le novità dei nuovi rilevamenti, al fine di poter fornire uno strumento utile a tutte le figure che operano sul territorio quotidianamente e che necessitano avere dati aggiornati.
The reinterpretation of public seismic profiles in the Adriatic offshore of Gargano (Apulia, southern Italy) allowed the detection of a kilometre-scale salt-anticline, the Tremiti diapir, within the larger Tremiti Structure. This anticline was generated by diapirism of Upper Triassic anhydrites within a thick Mesozoic to Quaternary basinal sedimentary succession. Both internal stratal patterns and shapes of Plio-Quaternary units, and the occurrence of an angular unconformity between early Tortonian and Pliocene rocks on the Tremiti Islands, suggest that halokinesis began during the late Miocene and is still active today. An ancient extensional SE dipping fault, cutting an older Mesozoic low-amplitude anhydritic ridge, played an important role during salt mobilization, which was promoted by NW-SE shortening. The diapir grew in the footwall of this fault, causing its upward propagation. In some places, the ancient fault served as a preferential channel for the upward migration of the anhydrites.
The area represented in the F° 438 “Bari”, at the scale 1:50.000, lies in the northern part of the Murge (Apulia region, southern Italy). The Murge is part of the Apulian Foreland, which represents the south-Apennines foreland made up of a uniform crustal structure with a Variscan crystalline basement and an approximately 6 km thick Mesozoic sedimentary cover overlain by relatively thin and discontinuous Tertiary and Quaternary deposits. The Mesozoic deposits extensively cropping out in the F° 438 “Bari” are represented by the Calcare di Bari Fm, showing in this area a thickness of 470 m. The lower and the upper boundaries of this formation do not crop out in the studied area. Mostly, the Calcare di Bari succession is made up of biopeloidal and peloidal wackestones/packstones alternated to stromatolitic bindstones with frequent intercalations of dolomitic limestones and grey dolostones. Mollusksrich layers (mostly rudist shells) with fl oatstone/rudstone texture occur in the lower and upper parts of the successions. These layers are easily recognizable in the fi eld and form up to some tens of meters thick strata sets. These strata sets were formerly used as reference layers (“livelli guida”) for lithostratigraphic correlations. They correspond to “livello Palese”, “livello Sannicandro” and “livello Toritto”, already recognized in the previous edition of Carta Geologica d’Italia. Furthermore, in the middle part of the succession, 20 thick dolomitic breccias alternate to massive dolostones laterally fading (towards east) in peritidal limestones. Due to these peculiar lithologic features, this lithofacies has been distinguished and mapped (lithofacies CBAa). The upper part of the succession is made up of fl oatstones/rudstones alternated to intrabioclastc rudstones and burrowed mudstones/wackestones. Most of the Calcare di Bari succession shows facies features related to peritidal environments; only the features of upper part suggest relatively more distal and deeper environments belonging to an external platform setting. The Calcare di Bari succession bears macro-(mollusks) and microfossils (benthic foraminifers), and the biostratigraphic data allowed us to refer the age of the whole succession of the Calcare di Bari Fm to the early Albian p.p.-late Cenomanian. The lower Pleistocene Calcarenite di Gravina Fm unconformably lies on the Calcare di Bari Fm. The lower boundary is transgressive and is locally marked by reddish residual deposits (terra rossa) and/or by brackish silty deposits passing upward to shallow-water calcarenites rich in bioclasts. Mainly this formation is made up of litho-bioclastic calcarenites and calcirudites with packstone/ grainstone texture, rich in mollusks, red algae, serpulids, echinoids and benthic foraminifers. The thickness of this unit ranges from few metres to 20 m, and its depositional environments are related to alluvial or offshore systems. The age is early Pleistocene (Gelasian ?-Calabrian). The argille subappenine fm conformably lies on the Calcarenite di Gravina Fm, and crops out only in a very restricted area in the southeastern corner of the sheet. The argille subappenine fm is made up of burrowed silty clays interbedded to dark grey marly clays, silts and fi ne-grained sand. The outcropping thickness is about 2 m, but by drilling data it appears at least 8 m. Frequently, mollusks, bryozoans and serpulids fragments are present; micropaleontological content is represented mainly by benthic foraminifers ad rarely by planctonic foraminifers and nannofossil. The facies features are related to offshore environments. The age is early Pleistocene (Calabrian). The Murge supersynthem groups all the marine terraced deposits unconformably lying on all older units and consists of a heterogeneous assemblage of mixed silicoclastic and carbonate sediments formed in shallow-marine and transitional environ
The stratigraphical analysis of several boreholes drilled in the Metaponto coastal plain (Basilicata region, southern Italy) highlighted the occurrence of two irregular erosional surfaces bounding three main overlapping sedimentary units. The upper unit, which base has been detected by using a geophysical method for the H/V spectral ratio (HVSR) of microtremors, fi lls and covers some paleovalleys that were incised during the Last Glacial Maximum (LGM). A 3D view of a main geophysical unconformity shows a surface with the occurrence of some deeper, narrow, and sinuous zones running roughly perpendicular to the present-day coastline and at depths of up to 90 m below the present-day sea level. These narrows likely correspond to the paleovalleys that developed in the region during the LGM and are buried below the Metaponto coastal plain. Some discrepancies between the geophysical and the geological data may be explained either as induced by a not well constrained projections of boreholes (from which derive the lithostratigraphic interpretations) or considering that the sedimentary models of incised-valley fi lls suggest the presence of different coeval deposits along dip through paleovalleys, inducing a contrast of seismic impedance readable as paleotopography rises.
The Metaponto Coastal Plain (MCP), in southern Italy, stretches 60 km-long and 5 km-wide along the Gulf of Taranto in the Ionian Sea, and is presently subject to strong anthropogenic pressure. A multidisciplinary study reviewed the geomorphology, lithostratigraphy and sedimentology of the MCP and its subsurface. Incorporating both borehole and radiocarbon-dating information in the review, this paper focuses on comparisons and differences between present-day and buried Late Pleistocene landscapes (LGM and MIS 3). The modern coastal plain is the top of a late Holocene coastal wedge prograding on a very narrow-shelf, that is connected to a deep basin (the Ionian Sea) by a steep slope. This scenery likely resembles those produced during earlier late Quaternary relative highstands and is in marked contrastwith that produced during the last sea-level fall and lowstand, and buried in the MCP subsurface. The last scenery corresponds to the LGM landscape, where river-valleys deeply dissected a previous highstand coastal wedge (MIS 3) whose remnants represented interfluve areas. Thanks to resonance properties of the subsurface, this buried landscape was obtained in a 3D visualization, highlighting location and shape of incised valleys and interfluve areas during the LGM.
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