Acropora (Scleractinia) from the Oligocene and Miocene of Europe: species longevity, origination and turnover following the Eocene–Oligocene transition

Four new species and new records for six species of the highly successful reef-building coral genus Acropora are described from Oligocene and Early Miocene (Rupelian to Burdigalian) localities in Europe. Acropora slovenica sp. nov. is described from Slovenia (Gornji Grad beds); A. piedmontensis sp. nov. and A. macrocalyx sp. nov. from the Torino Hills (Piedmont), and A. salentina sp. nov. from the Salento Peninsula (Apulia) of Italy. The remaining six species have an Eocene lineage. From south-west France, A. anglica and A. bartonensis, previously known from England (Priabonian and Bartonian), are recorded: A. anglica in Oligocene (Chattian) and both in Miocene (Aquitanian) deposits, indicating their persistence in the western Tethys for up to 17 and 20 million years respectively. Also recorded from Aquitaine is A. wilsonae (type locality Eocene Paris Basin), indicating persistence in western France for up to 28 million years. Italian material includes A. proteacea, also known from the Lower Bartonian of France and A. lavandulina, already known from Italy and the Eocene of France. From Slovenia (Oligocene, Rupelian), A. haidingeri is recorded, including from the type locality. The species are interpreted as representing seven extant species groups previously documented from the Eocene of Europe and the first records for two further extant groups. These results complement a previous finding of Eocene diversification of Acropora into the beginnings of up to 10 of the 20 recognized modern species groups in England and France. They indicate that the longevity of some Eocene taxa was extended into the Oligocene to Early Miocene of Europe and allowed some turnover, probably associated with changes in configuration of the western Tethys Sea. This information is important for interpreting molecular phylogenies and the evolution of modern Acropora diversity, by providing extended stratigraphical ranges for species groups with Eocene origins and dates of origination for two groups previously unrecorded in the early fossil record

New paleoenvironmental insights on the Miocene condensed phosphatic layer of Salento (southern Italy) unlocked by the coral-mollusc fossil archive

From the Late Oligocene to the Late Miocene, the central Mediterranean area was characterized by the extensive deposition of phosphate-rich sediments. They are usually represented by 10 to 20-cm-thick hardgrounds made of phosphatic and glauconitic sediments containing a rich macrofossil association. This study represents the first thorough investigation of the biotic assemblage of Mediterranean phosphorites aimed at collecting new information on the environmental factors controlling their deposition. The Serravallian/Tortonian phosphatic deposits of the Salento Peninsula (“Aturia level”) have been selected for the abundance of fossil remains and special attention is given to the coral–mollusc association. Two different facies have been recognized: a basal coral rudstone that includes most of the macrofossils, superimposed by a detrital rudstone made of thin layers mainly composed of phosphatic fragments. These two facies are separated by a phosphatic crust several millimeters in thickness. The coral assemblage contains at least 17 azooxanthellate taxa belonging to four families, while the molluscs are represented by a rich gastropod fauna (26 species), associated with bivalves (18 species) and cephalopods (two species). Four distinct depositional phases have been recognized, with the coral rudstone representing the key-facies to reconstruct the onset of the “Aturia level” and the original environment of its fossil content. The composition of the coral–mollusc association has been reliably compared with present-day analog taxa, suggesting the occurrence of a heterogeneous seafloor formed by rocky substrates and accumulations of soft sediment, at around 100–350-m water depth, and under the influence of moderate-to-strong bottom currents rich in nutrients and resuspended organic matter

Stratigraphic architecture of the Salento Coast from Capo d’Otranto to S.Maria di Leuca (Apulia, Southern Italy)

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

CARBONATE FACIES ZONATION OF THE UPPER JURASSIC-LOWER CRETACEOUS APULIA PLATFORM MARGIN (GARGANO PROMONTORY, SOUTHERN ITALY)

The Late Jurassic-Early Cretaceous Apulia platform margin and the transition to adjacent basinal deposits (inner platform to basin) are well exposed in the Gargano Promontory. Detailed field work has allowed to recognize eight main facies associations which reflect various depositional environments, and which document a differentiated zonation, from the inner platform to the basin. A shallow lagoon existed in the internal part of the Gargano Promontory with a transition to tidal flat areas (F1). Oolitic shoals (F2) bordered this internal peritidal area passing seaward to a reef-flat with abundant corals (F3). A reef-front, associated with a coral rubble zone, has been found in some areas (F4). In the external margin zone, massive wackestones with Ellipsactinia occur (F5) and pass gradually to a rudstone facies on the proximal slope (F6). The base-of-slope facies association consists of pelagic sediments interbedded with gravity-displaced deposits (F7 and F8). The depositional profile of the Apulia Platform is typical of the Tethyan Jurassic-Early Cretaceous platforms, with slope declivities in the order of 25°-28°. The remarkable progradation of the platform in the northern tract of the Gargano (Lesina and Varano lakes area) and its substantial stability east- and southwards (Mattinata area) suggest a possible windward position of the margin in this latter portion and, in contrast, a leeward position of the northern portion.  &nbsp

CARBONATE FACIES ZONATION OF THE UPPER JURASSIC-LOWER CRETACEOUS APULIA PLATFORM MARGIN (GARGANO PROMONTORY, SOUTHERN ITALY)

The Late Jurassic-Early Cretaceous Apulia platform margin and the transition to adjacent basinal deposits (inner platform to basin) are well exposed in the Gargano Promontory. Detailed field work has allowed to recognize eight main facies associations which reflect various depositional environments, and which document a differentiated zonation, from the inner platform to the basin. A shallow lagoon existed in the internal part of the Gargano Promontory with a transition to tidal flat areas (F1). Oolitic shoals (F2) bordered this internal peritidal area passing seaward to a reef-flat with abundant corals (F3). A reef-front, associated with a coral rubble zone, has been found in some areas (F4). In the external margin zone, massive wackestones with Ellipsactinia occur (F5) and pass gradually to a rudstone facies on the proximal slope (F6). The base-of-slope facies association consists of pelagic sediments interbedded with gravity-displaced deposits (F7 and F8). The depositional profile of the Apulia Platform is typical of the Tethyan Jurassic-Early Cretaceous platforms, with slope declivities in the order of 25°-28°. The remarkable progradation of the platform in the northern tract of the Gargano (Lesina and Varano lakes area) and its substantial stability east- and southwards (Mattinata area) suggest a possible windward position of the margin in this latter portion and, in contrast, a leeward position of the northern portion.  &nbsp

The Scleractinian genus Actinacis. Systematic revision and stratigraphic record of the Tertiary species with special regard to Italian occurrences.

Twenty-seven Tertiary species belonging to the cosmopolitan reef-building scleractinian genus Actinacis, have been described in the literature. A detailed systematic revision has been carried out for Italian and European species by thin section measurements. A combination of several measured corallite morphologic characters and diagnostic features is proposed as a realiable tool for species recognition. Preliminary examination of the stratigraphic and geographic distribution of Actinacis species suggests that: 1) the Tertiary distribution of the genus ranges from the Late Paleocene to the Late Oligocene; 2) the highest species diversity occrred during the Middle Eocene, when the genus consisted of a relatively large number of geographically restricted species; 3) only two widespread species survived the Eocene/Oligocene turnover and reached the Late Oligocene, when the genus became globally extinct

Coral facies and cyclicity in the Castelgomberto Limestone (Early Oligocene, Eastern Lessini Mountains, Northern Italy).

The Castelgomberto Limestone is a 200 m thick unit of Early Oligocene age (Rupelian) outcropping in the eastern Lessini Mountains (Southern Alps of Northern Italy). The internal cyclic organization of this Oligocene unit is described and analyzed on the basis of four selected sections; about 13 well-bedded grainstone units alternate with marly horizons rich in corals. This peculiar cyclicity is here interpreted as a response to variations in platform hydrodynamics, i.e. to smaller eustatic fluctuations affecting the Lessini Shelf reef-lagoonal complex. During highstand periods, the shelf was open and relatively deep (20-50m), and tidal currents and periodic storms were able to distribute bioclastic sands. During lowstands the shelf was more protected by the occurrence of marginal reefs and was colonized by patches of poritid corals, mainly branching. Moreover, the largely exposed northern areas supplied fine detritus to the shelf itself

STRATIGRAPHIC ARCHITECTURE OF THE SALENTO COAST FROM CAPO D'OTRANTO TO S.MARIA DI LEUCA (APULIA, SOUTHERN ITALY)

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.&nbsp