The Italian peninsula is an extremely active region from the geodynamic point of view as witnessed by the presence of active volcanoes (Vesuvius, Campi Flegrei, Stromboli, Vulcano, Etna) and by frequent earthquakes. Italian geology, however, is dominated by two different mountain chains, the Alps to the north and the Apennines to the south, along the peninsula. Geologically speaking, the Italian territory can be subdivided into seven specific sectors, i.e. The Alpine chain proper, the Po Plain, the Apennines, the Apulia foreland, the Calabrian-Peloritan arc, Sicily and Sardinia.

The phenomenon of subsidence induced by the growth of carbonate platforms has been investigated with the aid of numerical modelling. The research aimed to quantify the relative contribution of this process in the creation of the accommodation space required to pile up thick neritic bodies. We analysed two end-member deformation styles, namely the elastic behaviour of the lithosphere when locally loaded and the plastic-like reaction of a sedimentary succession underlying a growing carbonate buildup. The former process, analysed using a modified flexural model, generates a regional subsidence. In contrast, the latter process, simulated by considering the compaction occurring in soft sediments, generates a local subsidence. We attempted to quantify the amount and distribution of subsidence occurring below and surrounding an isolated platform and in the adjacent basin. The major parameters playing a role in the process are discussed in detail. The model is then applied to the Late Anisian-Early Ladinian generation of carbonate platforms of the Dolomites, Northern Italy, where they are spectacularly exposed. Taking also into account the Tertiary shortening that occurred in the area, both local and regional subsidence contributions of major platform bodies have been calculated aimed at a reconstruction of the map of the induced subsidence. A major outcome of this study is that the accommodation space, that allowed the accumulation of very thick shallow-water carbonate successions in the Dolomites, was only partially due to lithospheric stretching while the contribution given by the 'local' overload is as high as 20-40% of the total subsidence. Our results also shed some light on the water-depth problem of the Triassic basins as well as on the basin-depth to platform-thickness relationships.

Synthetic seismic models of outcrops in the Early Cretaceous slope of a carbonate platform on the Gargano Promontory (southern Italy) were compared to an offshore seismic section south of the Promontory. Outcrops of the same age on the promontory have the same sequence stratigraphic characteristics as their offshore equivalent, and are the only areas where the transition from platform to basin of Early Cretaceous is exposed on land. Two adjacent outcrop areas were combined into one seismic-scale lithologic model with the aid of photo mosaics, measured sections, and biostratigraphic data. Velocity, density, and porosity measurements on spot samples were used to construct the impedance model. Seismic models were generated by vertical incidence and finite difference programs. The results indicate that the reflections in the seismic model are controlled by the impedance contrast between low porous intervals rich in debris from the platform and highly porous intervals of pelagic lime mudstone, nearly devoid of debris. Finite difference seismic display showed best resemblance with the real seismic data, especially by mapping a drowning unconformity.

Spectacular seismic-scale outcrops in the «Montagna della Maiella» allow to observe directly an average 1000 m high Cretaceous escarpment, abruptly separating shallow-water deposits from slope to basin ones. In plain view, three km-scale amphitheatre-like indentations have been recognized. In section view, along the large scalloped indentations, the escarpment geometry has an exponential profile which changes downslope from high angle (~60°) to sub-horizontal. Along ridges, between different scallops, the escarpment profile is more regular, with average angles of 35° and locally steeper (> 45°). We interpret the Maiella escarpment and related morphologies, that are similar in shape and size to those observed in modern scalloped platform margins, as the result of different scale gravity-driven processes occurred during different stages. The larger indentations formed as the result of Albian platform margin collapses, exposing Lower Cretaceous inner platform facies directly to open marine conditions and exporting related products (megabreccias) many kilometres basinward. During the Upper Cretaceous, the inherited physiography controlled the spatial distribution of marginal facies, stratal geometries, basinward exportation of loose sediments and influenced the stratal stacking patterns in both platform and slope-basin settings. An overall aggrading margin characterized by the stacking of rudist dominated facies, re-shaped by smaller scale collapses, and a by-pass slope, developed up to the Campanian. At this time, the basin was almost completely filled and the platform started to prograde.

The understanding of carbonate platform reservoirs can be enhanced through the analysis of outcropping counterparts, such as the ones provided by the study platforms (Cernera and Latemar), particularly rich in both marine cements and microbial boundstones. The birth of both coeval platforms was matched with an anoxic event and with the deposition of a potential source horizon, rich in marine organic matter. The evolution of the short lived Cernera Platform was controlled by a very fast subsidence, badly compensated by its aggrading evolution. The lengthening slopes rapidly steeped up, while the cementation intensity increased. The carbonate production was unable to support the fast platform volume increase and the slope deposits therefore became thinner and thinner, forcing the margin to retrograde; the platform eventually drowned and it was covered by condensed pelagic facies and deep water stromatolite-like structures. The Latemar slope experienced a similar lengthening and steeping up evolution; this carbonate system however grew in a comparatively less subsiding area and it was therefore able to keep and eventually catch up the relative sea level increase. While the platform core shallowed from subtidal environments to cyclic emersions, in the adjacent slopes loose bioclastic and micritic sediments gave place to breccia rich in carbonate cements and microbial boundstones. The subsidence then slowed down considerably enabling the platform to laterally prograde, but no margin are presently preserved from this phase. Both platforms were then at least partially sealed by volcanic and terrigenous deposits and incompletely affected by a permeability enhancing dolomitization.

Evidence of a sizeable population of large dinosaurs on the Apulia carbonate platform calls for a revision of the current paleotectonic and paleogeographic scenario of the eastern Mediterranean area. A review of geophysical and geological data of the Ionian Sea and surrounding areas leads to envisage the Late Jurassic–Early Cretaceous Ionian Sea region as a “cul-de-sac”-type basin enclosed by shallow-water carbonate banks, connecting the Apulia carbonate platform to Peloponnesus, northern Cyrenaica, Cyrene Seamount and Medina Ridge. These banks were repeatedly and periodically exposed to subaerial conditions, and offered vast land areas for migration of dinosaurs. As regards the nature of the Mesozoic Ionian basin, interpretations are quite controversial. The “continental” vs. “oceanic” crust debate will likely be solved only when the Ionian basin crust will be reached by drilling. The conclusion of the present review leads to consider Adria as a true African Promontory and the Apulia Platform as a sort of Florida Peninsula, attached to North Africa (Cyrenaica spur), subdividing the oceanic(?) “Mesozoic Mediterranean” into a western Ionian basin and an eastern Levantine basin.

The Cretaceous to Quaternary succession of the Apulia Platform cropping out on the eastern coast of the Salento Peninsula shows a special stratigraphic architecture. Whereas on the platform top, i.e. on the Salento Peninsula proper, the succession is at most a few tens of metres thick and is punctuated by unconformities, on the margin and slope of the platform, along the present-day eastern coast of the peninsula, several carbonate systems are laterally disposed and grafted one upon the other. Three of these systems are clinostratified and include well developed reef tracts of Priabonian, early Chattian and early Messinian age. The geologic conclusion of our study is that, since the Late Cretaceous, the eastern coast of the Salento Peninsula grossly coincided with the margin of the Apulia Platform. This paleogeographic element acted as a foreland horst and registered important geodynamic events related to the growth of the adjacent Hellenide and Apennine thrust belts. During the last 60 m.y., the horst carapace was constantly near sea level and sediments were mainly accommodated and preserved on the deep margin and slope of the platform.

The occurrence of a thin band of marine limestone (Graua Limestone) within a thick succession of fluviatile sandstones in south-eastern Ethiopia is direct evidence of flooding of part of the East African craton (Horn of Africa). According to the presence of abundant orbitolinid foraminifers (Palorbitolina lenticularis Blumenbach andPraeorbitolina cormyi Schroeder), the age of the Graua Limestone can be referred to the Early Aptian. Stratigraphy and palaeogeographic reconstructions for the Early Cretaceous in the surrounding regions (Kenya, Somalia, Yemen, Socotra, Oman, Syria, Lebanon, Israel, Egypt and Libya) show that the Early Aptian transgression was of regional extent. Our data seem to confirm that this transgression was of relatively short duration. This pulse cannot be related to tectono-eustatic mechanisms, which are too slow. A short-lived event should be invoked: either a regional tectonic pulse or the desiccation of the proto-South Atlantic.

The study of two Lower Cretaceous stratigraphic sections from northern Gargano, Apulia, southern Italy, has shown that the classic succession of the Umbria-Marche Basin, central Italy, can be extended to the south as far as the Gargano Promontory. Here, the Cretaceous basinal succession consists of three formations: the Maiolica, the Scisti a Fucoidi and the Scaglia. Near the margin of the platform, the Mattinata Formation with frequent gravity-displaced deposits, laterally substitutes the Maiolica Formation. According to our integrated biostratigraphic data, and in agreement with the classic chronostratigraphic schemes proposed from the Umbria-Marche Basin, the Scisti a Fucoidi of northern Gargano correlates with the late part of the early Aptian (C. litterarius Zone p. p., L. cabri Zone) to the late Albian (lower pan of the P. achlyostaurion Zone and B. breggiensis Zone, T. praeticinensis Subzone). The occurrence of two anoxic episodes, which can be correlated with the 'Urbino level' and 'Amadeus segment' of the Umbria-Marche Basin, also strongly supports the proposed correlation of the two basins. (C) 1997 Academic Press Limited.

Nella sua area-tipo il Calcare di Antalo (Oxfordiano-Kimmeridgiano) risulta costituito da gruppi di cicli o parasequenze, retrogradanti nella parte inferiore, aggradanti in quella centrale e progradanti in quella superiore. Questa organizzazione stratigrafico-sequenziale è il risultato di un ciclo trasgressi-vo-regressivo che ha portato alla deposizione di una sequenza deposizionale di secondo ordine, costituita dal Calcare di Antalo e dal sovrastante Agulà Shale. Tale sequenza, qui denominata Sequenza di Macallè, si depositò su di una rampa a debolissima pendenza e può essere considerata l’equivalente cratonico della Sequenza di Uarandab, presente in prossimità del margine continentale est-africano.

We describe the sequence stratigraphic organization and the associated sedimentological characteristics of Cretaceous to Eocene slope and base‐of‐slope carbonate successions. The study area is located in the Gargano Promontory which belongs to the stable foreland of southern Italy. The succession consists of three superimposed depositional sequences separated by major unconformities. The upper two sequences are clear examples of sequence stratigraphic organization; in fact, they both start with huge megabreccia wedges (LST) followed upward by thin pelagic units (TST) and a thick package of calciturbidites and debrites that alternate with pelagic mudstone (HST). The Cretaceous highstand systems tract is clearly arranged in a number of coarsening‐upward cycles while the Eocene one which also comprises a toplap shallow water unit, is not.The Gargano stratigraphic palimpsest and the entire margin of the Apulia Platform show remarkable similarities with present‐day carbonate platform margins and slopes where irregular, convex‐bankward embayments suggest large‐scale failures. It is clear that classic sequence stratigraphic organization can result from simple platform dismantling, having no or little time relation with global sea‐level fluctuations. In fact, as the margin failure (LST) interrupts the carbonate production, a period of starvation (TST) along the entire slope and base‐of‐slope follows necessarily. Finally, when the margin once again becomes active and productive, sediment exportation starts again and the system begins to prograde (HST).

Field stratigraphic relationships observed in carbonate systems of various age (Triassic, Jurassic, Cretaceous, Eocene, Oligocene, Miocene) demonstrate that the response of carbonate platforms to relative sea-level changes can be quite diversified. Consequently, also the sequence stratigraphicorganization results different from one case to another and not so simple as suggested by current models. INTRODUCTION There is a general agreement that depositional sequences occur in most, if not all, sedimentary successions, and this makes sequence stratigraphy a nearly universally applicable technique for the study of the sedimentary record.1 Classical sequence stratigraphy states that most sediment is shed into basinal areas during Iow stands of sea level when shelves are exposed; during high stands, most sediment is thought to be trapped on the flooded inner shelf and on the aggrading coastal plain, while little escapes to the deep.2This principle of "low stand shedding" has been applied also to carbonate platforms, but, as suggested by many workers3 (see also references in 1), extant carbonate platforms clearly display the opposite trend. Shedding of sediment into the adjacent foresfope and deep basin implies also progradation of the platform. Similarly, many workers have proposed that carbonate platform progradation occurs primarily during relative high stands of sea level (see references in 3), while others suggest that significant progradation takes place during both high stands and low stands.4,5 The purpose of this article is to present evidence that carbonate sequence stratigraphy is not so simple as suggested by current models and that generalizations are dangerous and sometime fallacious. Field stratigraphic relationships observed in Italian carbonate depositional systems of various ages (Triassic, Jurassic, Cretaceous, Eocene, Oligocene, Miocene) demonstrate that the response of steep-sloped carbonate platforms to relative sea-level changes can be quite diversified. To avoid misleading interpretations, carbonate sequence stratigraphy should be carefully calibrated for each case, both in outcrop sections and seismic profiles. CARBONATE EXPORTATION:TWO DIFFERENT KINDS OF PRODUCTS Carbonate platforms build so close to sea level that even small rises and falls will alternatingly flood and expose the platform top and drastically affect the sediment production. But in which way? Unlike siliciclastics, which originate from erosion of older rocks, the majority of carbonate sediments (mud, peloids, skeletals, ooids, etc.) were born directly in the sea where they accumulate in relatively shallow-water conditions. These loose and soft sediments are frequently swept off bank by wind-generated currents and/or shed down the platform franks and adjacent basinai areas to produce wedges of unconsolidated sediments. It is obvious that this process is greatly enhanced when the platforms are flooded. The concept of high stand shedding of carbonate platforms implies that the sediment bodies on the franks and on the adjacent basin floor are largely high stand wedges. This concision, however, might be incorrect; it should be supported by the evidence that primary sediment (mud, grains) was originally loose.