A Cretaceous carbonate delta drift in the Montagna della Maiella, Italy

The Upper Cretaceous (Campanian\u2013Maastrichtian) bioclastic wedge of the Orfento Formation in the Montagna della Maiella, Italy, is compared to newly discovered contourite drifts in the Maldives. Like the drift deposits in the Maldives, the Orfento Formation fills a channel and builds a Miocene delta-shaped and mounded sedimentary body in the basin that is similar in size to the approximately 350 km 2 large coarse-grained bioclastic Miocene delta drifts in the Maldives. The composition of the bioclastic wedge of the Orfento Formation is also exclusively bioclastic debris sourced from the shallow-water areas and reworked clasts of the Orfento Formation itself. In the near mud-free succession, age-diagnostic fossils are sparse. The depositional textures vary from wackestone to float-rudstone and breccia/conglomerates, but rocks with grainstone and rudstone textures are the most common facies. In the channel, lensoid convex-upward breccias, cross-cutting channelized beds and thick grainstone lobes with abundant scours indicate alternating erosion and deposition from a high-energy current. In the basin, the mounded sedimentary body contains lobes with a divergent progradational geometry. The lobes are built by decametre thick composite megabeds consisting of sigmoidal clinoforms that typically have a channelized topset, a grainy foreset and a fine-grained bottomset with abundant irregular angular clasts. Up to 30 m thick channels filled with intraformational breccias and coarse grainstones pinch out downslope between the megabeds. In the distal portion of the wedge, stacked grainstone beds with foresets and reworked intraclasts document continuous sediment reworking and migration. The bioclastic wedge of the Orfento Formation has been variously interpreted as a succession of sea-level controlled slope deposits, a shoaling shoreface complex, or a carbonate tidal delta. Current-controlled delta drifts in the Maldives, however, offer a new interpretation because of their similarity in architecture and composition. These similarities include: (i) a feeder channel opening into the basin; (ii) an excavation moat at the exit of the channel; (iii) an overall mounded geometry with an apex that is in shallower water depth than the source channel; (iv) progradation of stacked lobes; (v) channels that pinch out in a basinward direction; and (vi) smaller channelized intervals that are arranged in a radial pattern. As a result, the Upper Cretaceous (Campanian\u2013Maastrichtian) bioclastic wedge of the Orfento Formation in the Montagna della Maiella, Italy, is here interpreted as a carbonate delta drift

U and Th content in the Central Apennines continental crust: a contribution to the determination of the geo-neutrinos flux at LNGS

The regional contribution to the geo-neutrino signal at Gran Sasso National Laboratory (LNGS) was determined based on a detailed geological, geochemical and geophysical study of the region. U and Th abundances of more than 50 samples representative of the main lithotypes belonging to the Mesozoic and Cenozoic sedimentary cover were analyzed. Sedimentary rocks were grouped into four main "Reservoirs" based on similar paleogeographic conditions and mineralogy. Basement rocks do not outcrop in the area. Thus U and Th in the Upper and Lower Crust of Valsugana and Ivrea-Verbano areas were analyzed. Based on geological and geophysical properties, relative abundances of the various reservoirs were calculated and used to obtain the weighted U and Th abundances for each of the three geological layers (Sedimentary Cover, Upper and Lower Crust). Using the available seismic profile as well as the stratigraphic records from a number of exploration wells, a 3D modelling was developed over an area of 2^{\circ}x2^{\circ} down to the Moho depth, for a total volume of about 1.2x10^6 km^3. This model allowed us to determine the volume of the various geological layers and eventually integrate the Th and U contents of the whole crust beneath LNGS. On this base the local contribution to the geo-neutrino flux (S) was calculated and added to the contribution given by the rest of the world, yielding a Refined Reference Model prediction for the geo-neutrino signal in the Borexino detector at LNGS: S(U) = (28.7 \pm 3.9) TNU and S(Th) = (7.5 \pm 1.0) TNU. An excess over the total flux of about 4 TNU was previously obtained by Mantovani et al. (2004) who calculated, based on general worldwide assumptions, a signal of 40.5 TNU. The considerable thickness of the sedimentary rocks, almost predominantly represented by U- and Th- poor carbonatic rocks in the area near LNGS, is responsible for this difference.Comment: 45 pages, 5 figures, 12 tables; accepted for publication in GC

Montagna della Maiella: Geometrie ed architettura deposizionale del margine settentrionale della Piattaforma Apula.

Guida alle successioni stratigrafiche della Montagna della Maiella, con descrizione degli stop

The Apulia carbonate platform margin and slope, Late Jurassic to Eocene of the Maiella and Gargano Promontory: physical stratigraphy and architecture.

Geology of the Maiella Mountain and Gargano Promontory. Evolution of the Apulia Carbonate Platform margin during the Cretaceous and Paleogene

Carbonate saturation state vs carbonate production rates in the geological past: in search for a paradigm

Saturation state with respect to carbonate (Ω) plays a crucial role in influencing carbonate precipitation in seawater, which is one of the fundamental processes of the global inorganic carbon cycle. It has been shown that a broad positive correlation exists between modeled variation of Ω in the past and the abundance of carbonates in the geological record. With the goal of investigating further the influence of Ω on the calcification process in the oceans, we have examined several carbonate platforms, with age ranging from the Devonian to the Neogene, and estimated an average carbonate production rate (G, expressed as a mass/unit time/unit surface) for each case study. This task required estimating the volumes of carbonates deposited in selected time intervals, and hence, platforms were chosen for being well age constrained and for the good outcrop conditions. The investigated platforms cover nearly 400 Myr of the geological record and are characterized by significantly different carbonate factories and modes of carbonate precipitation. We are aware that a number of factors (e.g. the existence of hiatuses) can affect such type of calculations; however, we coped with them by applying some corrections, where possible. For instance, a correction factor was applied to G estimates based on the evidence that the longer the time interval considered, the lower the observed accumulation rates because larger hiatuses are incorporated. When G estimates for the considered carbonate platforms are plotted in a log/log graph as a function of modeled Ω variations in the geological time (Ridgwell, 2005), they appear aligned and identify a logarithmic relationship. Such relationship closely resembles, and displays similar slope to, the empirical kinetic law that links G and Ω. A significant difference observed, however, is that Gs attained by carbonate platforms are higher than those predicted by the empirical kinetic law. Results of our investigation suggest that a power law linking G and Ω may govern precipitation in shallow water carbonate systems regardless of the organisms involved and, therefore, Ω could have been the main driver of global calcification in the geological past. The higher Gs attained by carbonate platforms with respect to those predicted by the empirical G/Ω kinetic law are consistent with laboratory evidence that biologically mediated calcification occurs at higher rates than inorganic precipitation. However, the fact that this is here observed considering ancient carbonate platforms dominated by different organisms, suggests that this biotic effect may be due to mechanisms that could be ecology¬ independent

Large-scale gravity-driven structures: control on margin architecture and related deposits of a Cretaceous carbonate platform (Montagna della Maiella, Central Apennines, Italy).

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

2D and 3D reconstruction of an erosional to by-pass margin and related slope deposits of a Cretaceous carbonate platform (Montagna della Maiella, Central Apennines)

none3noneRusciadelli G.; Milia M.L.; Morsilli M.Rusciadelli, G.; Milia, M. L.; Morsilli, Michel