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Heavy oil and bitumens have been exploited in Italy during the past, in particular over the Maiella Mountain's northwest flank (Central Italy), where relatively undeformed, hydrocarbon-bearing carbonateramp reservoirs of the Bolognano Formation crop out. These reservoirs represent the exhumed analog of a wider petroleum system that has been investigated also in the subsurface by exploration activities, both onshore and offshore (Central Adriatic). Here we present, for the first time, a historical data set composed of 180 shallow wells drilled over the area in 1942 by a company named Azienda Lavorazione Bitumi Asfalti; we digitally reconstructed this data set, integrating it with field observations, laboratory measurements, and thin-section analysis. Using Petrel (mark of Schlumberger) three-dimensional software, we modeled the reservoir and the hydrocarbon distribution, also calculating volumes of hydrocarbons in place. In our work, we demonstrate the presence of these quite homogeneous, porous carbonate reservoirs over the whole region, and we identify internal reservoir geometries characterized by clinoforms, likely resulting from a large-scale depositional cross-bedding and progradation. We also infer a different function of faults in the hydrocarbon accumulations: major faults were able to create independent compartments during migration, whereas minor, more recent elements did not control hydrocarbon accumulation, likely postdating a main lower-Pliocene migration phase. We believe that the observations derived from our work can represent a good analog for carbonate-ramp reservoirs elsewhere, may help in identifying appropriate modeling solutions, and can be used as calibration for future renewed exploration efforts in the region, both onshore and offshore. [ABSTRACT FROM AUTHOR]

The Miocene is a key interval in the geodynamic and oceanographic evolution of the Mediterranean marking the transition from a wide open basin to the modern closed basin. We used the Sr and Nd isotope records of two Miocene carbonate successions in the Adriatic to document that the evolution of the Mediterranean Basin controlled its seawater chemistry. During the late Aquitanian (~21 Ma), a time of glaciation and sea level lowstand, increased runoff affected the Sr isotope ratios of Mediterranean waters, whereas during the Burdigalian (20.44–15.97 Ma) volcanism in the circum-Mediterranean area mainly influenced the Sr isotopic signature. During the Langhian (15.97–13.82 Ma), a time of sea level highstand associated with the Middle Miocene Climatic Optimum, the Nd isotope values indicate that waters exchanged between the Paratethys and the Central Mediterranean. The Central Mediterranean was well connected with the Atlantic Ocean between the Langhian and the early Tortonian (15.97–11.5 Ma), but exchange of water with the Paratethys declined. In the Messinian (6.3 Ma), connections between some marginal Mediterranean basins, for example, the proto-Adriatic basin, and the Central Mediterranean, became restricted. In this basin, the Sr isotope values fell below the global reference line, while Nd isotope ratios show a strong affinity with the Atlantic Ocean and also indicate freshwater input. We conclude that the Mediterranean Nd isotope signature differs from that in the open oceans and reflects the basin physiography, reflecting a mix of signals derived from the adjacent oceans and local signals. The Central Mediterranean was mainly influenced by the Indo-Pacific in the Aquitanian, by Mediterranean volcanism in the BurdigalianMiddle Miocene Nd isotopes show that there was an open connection with the Paratethys during the sea level highstandIn the early Messinian, restricted conditions started in Mediterranean marginal basins such as the proto-Adriatic

In this study, calcareous nannofossils have been used for refining the biostratigraphic classification and chronology of a neritic Paleogene sedimentary succession, outcropping in the Central Apennines (Italy) and belonging to the ,,Santo Spirito Formation". Calcareous nannofossils are typically found in deep-sea sediments, but proved to be consistently present and useful also in these shallow-water deposits. The obtained biostratigraphic results benefitted from the random occurrence of rich and diversified nannofossil assemblages in chalky sediments, found inside chert nodules and as thin layers, within the dominant calcarenitic lithology of this lithostratigraphic unit. The observed well-preserved assemblages provided a reliable biostratigraphic framework that was completed with the analysis of intervening samples obtained from scattered layers of calcareous marls. In the two studied sections, Pennapiedimonte and Lettomanoppello sections, we recognize a series of biozones that integrate with the known biostratigraphy based on large and planktonic foraminifera. Overall, we provide a reliable chronology indicating that the stratigraphic succession of Santo Spirito Fm, in the investigated area, is constrained between ~ 42 Ma (late Lutetian) and ~ 31 Ma (early Rupelian). This precise stratigraphic assignment extends of ~ 2 m. y. the time lapse of sedimentation of the middle and upper Santo Spirito Fm, previously considered in these sections as limited to upper Bartonian-lower Rupelian. The obtained more accurate chronology is helpful for an ongoing study addressed to perform a detailed sequence stratigraphic interpretation of the unit, specifically to recognize higher rank depositional sequences within it. Moreover, our data evidence that the Eocene/Oligocene transition, with the intervening large transient glaciation event ,,Oi1", is represented in the sediments of S. Spirito Fm, suggesting that further studies in this area could provide new information on the response of this global climatic event in shallow-water marginal environments.

Abstract: This study presents a detailed facies analysis and paleodepth reconstruction of a coral-rich mixed siliciclastic-carbonate system Burdigalian in age, outcropping in the northern sector of Sardinia (Capo Testa). Excellent exposures of continuous sea-cliff outcrops around the southwestern and northeastern area of Capo Testa promontory allowed us to: (1) trace stratigraphic surfaces; (2) document stratal geometries; (3) discern details of the lithofacies and, (4) reconstruct the paleodepths of the different depositional environments. A total of seven sedimentary facies has been recognized and interpreted: siliciclastic conglomerate and coarse bioclastic sandstone (F1), fine- to medium-grained hybrid sandstone (F2, scleractinian coral domestone (F3), bioclastic packstone to floatstone with platy Porites (F4), red algae floatstone to rudstone (F5), larger benthic foraminifers (LBF) bioclastic rudstone floatstone in a packstone matrix (F6), molluscan floatstone in a bioclastic packstone matrix (F7). The investigated system is characterized by nearshore to shoreface deposits with a conspicuous terrigenous content that grades seaward into deeper zones where coral patch-reefs developed in association with adjacent areas colonized by seagrass meadows. The more distal facies are constituted by scattered encrusting tabular colonies of Porites in growth position occurring in a deeper and lower-energy environment. The paleodepth interval that is observed in the Capo Testa outcrop ranges from 0 to 50 m.

Abstract: Deglacial reefs from Tahiti (IODP 310) feature a co-occurrence of zooxanthellate corals with microbialites that compose up to 80 vol% of the reef framework. The notion that microbialites tend to form in more nutrient-rich environments has previously led to the concept that such encrustations are considerably younger than the coral framework, and that they have formed in deeper storeys of the reef edifice, or that they represent severe disturbances of the reef ecosystem. As indicated by their repetitive interbedding with coralline red algae, the microbialites of this reef succession of Tahiti, however, formed immediately after coral growth under photic conditions. Clearly, the deglacial reef microbialites present in the IODP 310 cores did not follow disturbances such as drowning or suffocation by terrestrial material, and are not “disaster forms”. Given that the corals and the microbialites developed in close spatial proximity, highly elevated nutrient levels caused by fluvial or groundwater transport from the volcanic hinterland are an unlikely cause for the exceptionally voluminous development of microbialites. That voluminous deglacial reef microbialites generally are restricted to volcanic islands, however, implies that moderately, and possibly episodically elevated nutrient levels favored this type of microbialite formation.