196,430 research outputs found
Empirical insights into multi-grain averaging effects from 'pseudo' single-grain OSL measurements
No full textAbstract not availableL.J. Arnold, M. Demuro, M. Navazo Rui
Continuità dei rapporti giuridici
No full textIl saggio studia e approfondisce la conseguenze della trasformazione di società nei rapporti giuridici pendent
Opposizione dei creditori
No full textIl saggio studia le conseguenze della trasfomazione sui creditori sociali e la possibilità di opposizione da parte di quest
La tutela paesistico-ambientale tra interessi territoriali "speciali" e generali esigenze di uniformità
No full textAumenti di capitale
No full textNel commento si analizza la disciplina degli aumenti dela capitale sociale nelle società quotate, dando conto dell'evoluzione della disciplin
Poteri della Consob
No full textNel comemnto si evienziano i poteri della Consob, dando conto dell'evoluzione normativ
FACIES ACUSTICHE E STRUTTURE DI FONDO DELL’ULTIMO CICLO EUSTATICO NEI CANALI DELL’ARCIPELAGO DI LA MADDALENA (SARDEGNA SETTENTRIONALE)
No full textAcoustic facies and morphologies of the last eustatic cycle in the La Maddalena Archipelago (North Sardinia, Italy)
A high-resolution Chirp acoustic survey of 250 nautical miles performed in the La Maddalena Archipelago provided a scheme of the acoustic facies of the recentmost sediments and a frame of the large-scale bedforms linked to the last eustatic cycle that characterize the channels of the Archipelago. Five main acoustic facies have been recognized and mapped. Due to the good coherence with the sediment texture map of the area, a rough interpretation of the acoustic facies in sedimentary terms is also possible.
The Archipelago is characterized by a complex system of inlets, promontories, bays and channels ruled by the main tectonic trends of the region. A main, 20 km-long channel (also known as Bucinara Channel) with numerous straits and some shoals, roughly oriented WNWESE,divides the northern Sardinia coast from the main islands of Spargi, La Maddalena, Santo Stefano and Caprera. A shorter and larger, W-E trending channel occurs in the northern part of the Archipelago. Two minor, roughly N-S trending sea branches connect these channels.
The bathymetry of the area reveals that the channels generally have a flat bottom and steep flanks, their depth ranging from – 30 and – 60 m, with the exception of saddles and shoals.
The sedimentary regime of the area is controlled by storm-induced currents and by the high carbonate production of the Posidonia Oceanica seagrass, a marine Phanerogama that populate the flanks of the channels of the Archipelago.
A multitude of morphologic forms can be attributed to the phases of falling, low-standing, rising and high-standing of the last Pleisto-Holocene eustatic cycle. Angular unconformities,gullies and sediment-incised palaeo channels along with abrasion platforms in the granitic basement witness the Würmian sea-level fall and low-standing. These forms now lie at depths ranging from -33 m to -70 m and are covered by a thin veneer of sediments of the Holocene transgression.
They have all been formed when the sea-level was about -110 m below the present datum and the Archipelago was a landscape of rocky hills separated by large, flat valleys scoured by torrent-like rivers.
The Holocene rising of sea-level (Versilian transgression) caused the flooding of the landscape and the deposition of the thin sedimentary cover imaged by the acoustic profiles.
The rising was punctuated by some sea-level still stands evidenced by terraced surfaces at depths comprised between -33 m and -47 m which are coherent with the mapped and dated beachrocks of the Bocche di Bonifacio strait.
The slowdown of the rising between 6000 and 5000 years B.P. was responsible for the present sedimentary and hydrodynamic conditions of the area which is dominated by an eastward (Tyrrenian) trending sea current, and subordinately by a westward trending current.
In the two main WNW-ESE and W-E trending channels of the Archipelago, the current flows formed some longitudinal sand ridges up to 3 km long and 5 m high, while in the N-S oriented channels, transversal sand banks up to 10 m thick occur. Sea-floor undulations, interpreted as sand waves, are present in some restricted areas close to the Sardinia coast in underflow position with respect to the headlands. Their wavelength (L) ranges from 10 to 40 m and the height(H) is up to 1,5 m, the ratio H/L being 1:20 to 1:30. Those of symmetric shape are due to wave motion during stormy seas. The asymmetric ones, instead, are likely to originate from bottom currents.
Their steeper side faces to the East, according to the direction of the dominant current
Insights into the late stages of the Acheulean technocomplex of Western Iberia from the Arbo site (Galicia, Spain)
No full textThe arrival and disappearance of the Acheulean technocomplex in Europe, and specifically in the Iberian Peninsula, is a longstanding topic of discussion with relevance for unravelling the Middle Pleistocene human occupation dynamics of the continent. Despite containing one of the first Acheulean sites excavated in Europe (As Gándaras de Budiño site), the Miño River basin (north-western Iberian Peninsula) remains understudied and has yielded relatively limited information on the temporal and spatial dynamics of the regional Acheulean technocomplex over the last fifty years. Here we present a systematic archaeological and numerical dating study of a previously undocumented Acheulean site located in the lower Miño River basin (Arbo site, Pontevedra, Spain). This newly discovered site preserves a late Middle Pleistocene Acheulean assemblage that has been dated to pre-Marine Isotope Stage 5 by a combination of post-infrared infrared stimulated luminescence (pIR-IR) and electron spin resonance (ESR) dating of sedimentary silicates. The new excavations reveal that the site preserves a dense concentration of artefacts made from allochthonous raw materials. Detailed lithic analyses show that the industry has some elementary flake production systems devoid of Levallois cores, but with supplementary non-standardised flake tool types and some large cutting tools (LCTs) - mainly handaxes that are usually finalized with soft-hammer. The results obtained at Arbo complement those obtained recently at the nearby Porto Maior site, as well as the seminal study of As Gándaras de Budiño, and demonstrate an important Acheulean and hominin presence in the Miño River basin during the second half of the Middle Pleistocene.E. Méndez-Quintas, M. Demuro, L.J. Arnold, M. Duval, A. Pérez-González, M. Santonj
ESR and OSL dating of fossil-bearing deposits from Naracoorte Cave Complex palaeontological sites, south Australia
No full textAvailable online 5 March 2022Little work has been undertaken on combined dating of sedimentary quartz grains using electron spin resonance (ESR) and optically stimulated luminescence (OSL) techniques in Australia. This study aims to assess the suitability of a combined ESR and OSL dating approach for establishing improved chronologies of Middle-Late Pleistocene deposits within the Naracoorte Cave Complex (NCC), South Australia. Here, we apply ESR and OSL dating in tandem to a series of samples collected from three different NCC sites: Whale Bone, Specimen and Alexandra cave. ESR quartz dating focuses on the multi-centre (MC) approach, which involves comparative evaluations of Al and Ti centre signals, while paired luminescence dating focuses on single-grain OSL analysis and includes examination of multi-grain averaging effects. The comparative ESR-OSL dating results exhibit broad agreement for deposits spanning 50–150 thousand years, with either the Ti–H or Al centre ages overlapping with paired OSL ages at 2σ in nearly all cases. MC ESR evaluations (Al v Ti–Li v Ti–H age assessments) indicate incomplete resetting of the bleachable Al centre signal for a small number of samples. Two-thirds of samples exhibit Ti–Li ages that are significantly older than corresponding Al centre ages, which is unexpected from a bleaching kinetics perspective and may indicate a broader reliability issue for Ti–Li palaeodose evaluation with these particular samples. Our findings: (i) support the applicability of both palaeodosimetric dating methods in this depositional setting; (ii) highlight the merits of applying combined ESR-OSL analyses in tandem, and; (iii) provide one of the first reliable evaluations of quartz ESR MC dating for samples with natural dose ranges as low as only a few tens of Gy. These results show that the Whale Bone, Specimen and Alexandra cave sites are temporally related and can be used to derive multi-site reconstructions of faunal assemblages and palaeoenvironmental history.Priya, L.J. Arnold, V. Guilarte, M. Duval, M. Demuro, R. Weij, E.H. Ree
Luminescence dating and palaeomagnetic age constraint on hominins from Sima de los Huesos, Atapuerca, Spain
No full textAbstract not availableLee J. Arnold, Martina Demuro, Josep M. Parés, Juan Luis Arsuaga, Arantza Aranburu, José María Bermúdez de Castro, Eudald Carbonel
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