When Did Cosmic Acceleration Start ?

A precise determination, and comparison, of the epoch of the onset of cosmic acceleration, at redshift z_acc, and of dark energy domination, at z_eq, provides an interesting measure with which to parameterize dark energy models. By combining several cosmological datasets we place constraints on the redshift and age of cosmological acceleration. For a Lambda-CDM model, we find the constraint z_acc=0.76\pm0.10 at 95% c.l., occurring 6.7\pm0.4 Gyrs ago. Allowing a constant equation of state but different from -1 changes the constraints to z_acc=0.81\pm0.12 (6.9\pm0.5 Gyrs ago) and z_eq=0.48\pm0.14(4.9\pm0.9 Gyrs ago), while dynamical models markedly increase the error on the constraints with z_acc=0.81\pm0.30 (6.8\pm1.4 Gyrs ago) and z_eq=0.44\pm0.20 (4.5\pm1.0 Gyrs ago). Unified dark energy models as Silent Quartessence yield: z_acc=0.80\pm0.16 (6.8\pm0.6 Gyrs ago).Comment: 5 pages, 2 figure

Gis and landscape analysis

Landscape is “an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors” (Council of Europe, European Landscape Convention, 2000). The changing conditions of this complex factor, that determines the variability of our local and national contexts in Europe, can be effectively measured thanks to quantitative and qualitative indicators. These values could be calculated through procedures implemented thanks to Geographical information systems (GIS), using elements of geostatistics and numeric cartography. The speculative basics of the need of using GIS for the landscape analysis is strongly connected to the necessity of finding a steadier definition of its variability in time and space, mainly in a context like the European Union, that is in constant demand for procedures that could be standardized as best practices

Rhinocerotidae from the Upper Miocene deposits of the Western Pannonian Basin (Hungary): implications for migration routes and biogeography

Abstract Although the rhinoceros remains have high biochronological significance, they are poorly known or scarcely documented in the uppermost Miocene deposits of Europe. Several specimens collected from the Upper Miocene (around 7.0 Ma, Turolian) deposits of Kávás (Pannonian Basin, Western Hungary), previously determined as Rhinoceros sp., are revised and described in this paper. The postcranial remains of these specimens belong to "Dihoplus" megarhinus (de Christol) on the basis of the morphological and morphometric characters of humerus, radii, metacarpal and metatarsal elements. An overview of rhinoceros remains from several uppermost Miocene localities and the revision of the rhinoceros material from the Pannonian Basin suggest that "D." megarhinus spread during the latest Miocene from the Pannonian Basin towards Italy. The occurrences of this species in Western Hungary and Italy during the latest Miocene further imply that Rhinocerotini species were biogeographically segregated between Western, Southern and Central Europe

GIS AND LANDSCAPE ANALYSIS

Landscape is “an area, as perceived by people, whose character is the result of the action and interaction of natural and/or human factors” (Council of Europe, European Landscape Convention, 2000). The changing conditions of this complex factor, that determines the variability of our local and national contexts in Europe, can be effectively measured thanks to quantitative and qualitative indicators. These values could be calculated through procedures implemented thanks to Geographical information systems (GIS), using elements of geostatistics and numeric cartography. The speculative basics of the need of using GIS for the landscape analysis is strongly connected to the necessity of finding a steadier definition of its variability in time and space, mainly in a context like the European Union, that is in constant demand for procedures that could be standardized as best practices

Fluid flow during accretion in sediment-dominated margins: evidences of a high-permeability fossil fault zone from the Internal Ligurian accretionary units of the northern Apennines, Italy

We report here a detailed structural study carried out in the Internal Ligurian Units of the Northern Apennines, Italy, formed during the building of the Alpine accretionary complex through subduction of the sediment-filled Ligure-Piemontese oceanic basin. The deformation mechanisms associated with fluid migration across an accretion-related fault zone have been studied through a detailed analysis of different generations of syn-tectonic veins. Hydrofracturing occurred mainly sub-parallel to bedding in unlithified to semi-lithified sediments. Transient, upward-directed fluid injection locally connected the de´collement-parallel veins through bedding-normal hydrofractures of lithified sandstone layers. A third vein system comprises fibrous hydrofractures developed on the limbs of accretion-related folds. Crosscutting vein sets and the peculiar features of each identified vein set suggest that deformation was intricately associated with lithification and diagenetic processes. Dehydration-produced fluids transiently injected the lithifying sediments leading to local stress permutations. The proposed model provides a ‘‘ramp-flat’’ migration of fluids in which fluid flow is enhanced along high permeability, less cohesive layers, leading to the development of regional dilated hydrofracture channels like those recognized along the de´collement zone of modern margins. The more competent layers are truncated by high angle fractures representing the transient connectivity that existed between horizontal conduits

The basal part Modino Unit Succession under the belt-foredeep system of the Northern Apennines (Italy)

The Modino Unit turbidite system of the Northern Apennines foreland basin provides an excellent opportunity to study the sedimentary and structural variations within the context of spatial and temporal distribuition of source rocks during the evolution of foreland basins. The substrate of this Unit was interpreted as a stratigraphic-structural mélange (Plesi et al., 2000), the expression of polyphase tectonic phases of Cretaceous-Eocene accretion that have affected the external part of Ligurian and Subligurian domain. In this article we present the preliminary data of different stratigraphic sections outcropping in Tuscan and Emilian regions, with particulary attention to the lower part of Modino Unit Succession, of pre-Ligurian stage, unconformably deposited at the top of the Ligurian and Subligurian substrate, composed by Fiumalbo Shale Fm. and Marmoreto Marl Fm. The tectonic setting of this Unit is complex and necessitated the use of stratigraphical, biostratigraphical and petrographical studies to achieve this goals. The Modino Unit succession is composed by three different formations: The Fiumalbo Shale Fm. followed in some sections of coarse breccia deposits that cover the substrate (Riccovolto Breccia) are made up of mostly red and green shales with intercalations of limestone and turbidite-like sandstones beds more or less extensive (Rio Acquicciola Sandstones Auctt. or M. Sassolera Sandstones Auctt.). The Marmoreto Marl Fm. are characterized by fine emipelagic sediments, have a massive structure (with rare thin layers of fine sandstones). The Monte Modino Sandstone Fm. are constituted by one or more sequences of turbidite facies with quite variable vertically and laterally . Their deposition occurs preferentially in the middle and front al part of the prism and is quickly interrupted, on its southwestern margin, by the thrust belt materials. From this reason the axis of sedimentation moving outwards. A petrographical study on turbidite-like sandstone beds in Fiumalbo Shale Fm., show a petrofacies characterized by a modal composition of Q48F27L+CE25, according with the composition of Monte Modino Sandstone of this study, while shows different composition in the Fine-Grained Rock Fragments Compositional Mode (LmLvLs plot). The sandstones in Fiumalbo Shale Fm., are composed by different tipology of fine grained lithic fragments, and its composition changes strata-strata in the same stratigraphic sections. The fine grained lithic fragments are composed by dominating metamorphic origin clasts and ophiolithic rock fragment associated with unmetamorphic radiolaritic fragments, The biostratigraphical analysis indicate that the age of theese formations is comprised between Lutetian and Chattian ages. These formations reflect a slope environment, with quite deep and with a strong affinity to Epiligurian sections, which resemble the coeval succession Monte Piano-Ranzano and their sedimentation environment reflects a time and an area of major physiographic expression of the prism. The composition of this arenites is interpreted as being controlled mainly by synsedimentary tectonics connected with the evolution of an accretionary prism east vergent. This composition reflects the different stages of the process of accretion and is the expression of the different sedimentary environments that were gradually generating. The lower part of Modino Unit succession seems to be supplied by two different source areas, the classic Alpine source area and a more proximal "Liguride derived" source, maybe located in the proto-appenninic wedge

Large mammal remains from the early pleistocene site of Podere San Lorenzo (Perugia, Central Italy)

Most of the research on fossil mammals from Umbria (central Italy) has been carried out in the southwestern branch of the Tiber basin, due to its paleontological richness. This portion of the basin extends from Perugia to Terni and corresponds to a well-defined half-graben filled with fluvial-lacustrine deposits. The paleontological sample presented here was discovered in a sand and gravel quarry at Podere San Lorenzo, East of the town of Deruta. The stratigraphic succession exposed in the quarry is no longer visible, but we describe here a new outcrop (Palazzone), which is not far from Podere San Lorenzo and shows comparable facies associations. The two successions were deposited in a fluvial environment characterized by an average reduction of the hydrodynamic energy from the bottom upwards. They are referred to the Early Pleistocene Santa Maria di Ciciliano Subsyntheme (Madonna dei Bagni Lithofacies). Large mammal remains are attributed to Mammuthus cf. meridionalis (Nesti, 1825), Stephanorhinus etruscus (Falconer, 1859), Equus stenonis Cocchi, 1867, Leptobos cf. etruscus (Falconer, 1868), ‘Pseudodama’ nestii (Azzaroli, 1947), and Sus strozzii Forsyth Major, 1881. Some hyena coprolites are also reported. The assemblage is typical of the early Late Villafranchian Land Mammal Age and can be referred to the Olivola/Tasso Faunal Units (about 2.0–1.8 Ma). This is in agreement with the alleged age of some other assemblages found in the southwestern branch of the Tiber basin (e.g., Torre Picchio, Villa San Faustino, Colle Sant’Andrea, Pantalla)