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

Note Illustrative della Carta geologica d'Italia alla scala 1:50.000, F. 351 Pescara

<p>Foglio geologico alla scala 1:50.000 basato su rilevamenti alla scala 1:10.000 (eseguiti tra il 2004 e il 2006) comprensivo di legenda, schemi a cornice, sezioni geologiche.</p&gt

CORAL COMMUNITIES, ZONATION AND PALEOECOLOGY OF AN UPPER JURASSIC REEF COMPLEX (ELLIPSACTINIA LIMESTONES, CENTRAL APENNINES, ITALY)

This work describes and analyzes an original collection of fossil corals from the Ellipsactinia Limestones (Kimmeridgian-Tithonian), exposed in the Marsica area (central Apennines, Italy), focusing on taxonomy and paleoecology. 43 species grouped into 32 genera, 16 families and 9 suborders were identified. Astreoidogyra giadae nov. gen. nov. sp. (Rhipidogyridae) and Clausastrea eliasovae nov. sp. (Montlivaltiidae) are new taxa. Corals occur from the back reef to the reef crest, showing a marked zonation, expressed by a variation of coral cover and type, although the reef front and slope facies could not be sampled. The back reef is characterised by scattered medium-to-small colonies, with a relative high variety of colony shape, corallite arrangement types and high taxonomic diversity. Stylosmilia, Calamophylliopsis, Intersmilia, Pleurophyllia, Bracthelia, Heliocoenia, Ogilvinella occur here among others. The inner reef flat records the highest coral cover, with large robust branching, such as “Pseudocoenia”, Heliocoenia, Calamophylliopsis, and large dome-shaped meandroid, such as Psammogyra, Pruvostrastraea, Eugyriopsis) colonies. Within the external reef flat and the reef crest the coral cover is low and the stromatoporoid-bearing mounds dominate on the isolated coral bioconstructions. Controlling factors as bathymetry, hydrodynamic disturbances, abrasive currents, background sedimentation and morphological irregularities of the depositional profile are considered to explain the observed coral zonation. High diversity and low dominance indices are interpreted to result from reef complex heterogeneity, which should have influenced the formation of different ecological niches and consequently the proliferation of a greater number of taxa in a relatively small area

Submarine sediment routing over a blocky mass-transport deposit in the Espírito Santo Basin, SE Brazil

The control of slide blocks on slope depositional systems is investigated in a high-quality 3D seismic volume from the Espírito Santo Basin, SE Brazil. Seismic interpretation and statistical methods were used to understand the effect of differential compaction on strata proximal to the headwall of a blocky mass-transport deposit (MTD), where blocks are large and undisturbed (remnant), and in the distal part of this same deposit. The distal part contains smaller rafted blocks that moved and deformed with the MTD. Upon their emplacement, the positive topographic relief of blocks created a rugged seafloor, confining sediment pathways and creating accommodation space for slope sediment. In parallel, competent blocks resisted compaction more than the surrounding debrite matrix during early burial. This resulted in differential compaction between competent blocks and soft flanking strata, in a process that was able to maintain a rugged seafloor for >5 Ma after burial. Around the largest blocks, a cluster of striations associated with a submarine channel bypassed these obstructions on the slope and, as a result, reflects important deflection by blocks and compaction-related folds that were obstructing turbidite flows. Log-log graphs were made to compare the width and height of different stratigraphic elements; blocks, depocentres, and channels. There is a strong correlation between the sizes of each element, but with each subsequent stage (block – depocentre – channel) displaying marked reductions in height. Blocky MTDs found on passive margins across the globe are likely to experience similar effects during early burial to those documented in this work

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

Note Illustrative della Carta geologica d'Italia alla scala 1:50.000, F. 372 Vasto

<p>Note illustrative redatte per il Foglio geologico n. 372 Vasto della Carta Geologica d'Italia alla scala 1:50.000. 130 pp.</p&gt

Coral carbonate production during the Paleocene: insights from the Maiella Massif (Pennapiedimonte, Central Italy)

[eng] The succession of the Maiella massif is analyzed, focusing on the colonial-coral bearing deposits occurring just below and immediately above the Cretaceous/Paleogene boundary. The Upper Cretaceous material is dominated by rudists and larger benthic foraminifera with a significant contribution from colonial corals. In the Lower Paleocene, the first two groups are absent and colonial corals dominate the skeletal assemblage. This supports the hypothesis of a good recovery of colonial corals carbonate production following the end Cretaceous extinction and their overall resilience. Similar to modern reefs, Lower Paleocene bioconstructions have a framework dominated by corals and red calcareous algae. However, unlike modern reefs, micrite makes up the vast majority of the internal sediment, suggesting a development into a low-energy environment. Compared to Upper Paleocene coral boundstones, those from the Lower Paleocene of Maiella display a higher abundance of corals, suggesting a reduction in coral carbonate production during the Late Paleocene. This decline is also reflected by a period of scarcity of coral-dominated facies throughout the Tethys, starting from the latest Paleocene and extending till the end of the Middle Eocene. This can be connected to global temperatures, which rise in the Thanetian and remain relatively high till the end of the Middle Eocene, however, other factors most likely played a role. The quantitative analysis of the skeletal assemblage turns out to be a useful instrument for tracking the effect of environmental changes. Further data, especially from long and extensive successions of neritic carbonates such as those of Maiella, may help in disentangling the effects of the other environmental variables