The Afragola settlement near Vesuvius,Italy: The destruction and abandonment of a Bronze Age village revealed by archaeology,volcanology and rock-magnetism     

Mauro A. Di Vito  Elena Zanella  Lucia Gurioli  Roberto Lanza  Roberto Sulpizio  Jim Bishop  Evdokia Tema  Giuliana Boenzi  Elena Laforgia 《Earth and Planetary Science Letters》2009,277(3-4):408-421

Public works in progress in the Campanian plain north of Somma-Vesuvius recently encountered the remains of a prehistoric settlement close to the town of Afragola. Rescue excavations brought to light a Bronze Age village partially destroyed and buried by pyroclastic density currents (PDCs) of the Vesuvian Pomici di Avellino eruption (3.8 ¹⁴C ka BP) and subsequently sealed by alluvial deposits. Volcanological and rock-magnetic investigations supplemented the excavations.Careful comparison between volcanological and archaeological stratigraphies led to an understanding of the timing of the damage the buildings suffered when they were struck by a series of PDCs. The first engulfed the village, located some 14 km to the north of the inferred vent, and penetrated into the dwellings without causing major damage. The buildings were able to withstand the weak dynamic pressure of the currents and deviate their path, as shown by the magnetic fabric analyses. Some later collapsed under the load of the deposits piled up by successive currents. Stepwise demagnetization of the thermal remanent magnetization (TRM) carried by potsherds embedded in the deposits yields deposition temperatures in the order of 260–320 °C, fully consistent with those derived from pottery and lithic fragments from other distal and proximal sites. The fairly uniform temperature of the deposits is here ascribed to the lack of pervasive air entrainment into the currents. This, in turn, resulted from the lack of major topographical obstacles along the flat plain.The coupling of structural damage and sedimentological analyses indicates that the currents were not destructive in the Afragola area, but TRM data indicate they were still hot enough to cause death or severe injury to humans and animals. The successful escape of the entire population is apparent from the lack of human remains and from thousands of human footprints on the surface of the deposits left by the first PDCs. People were thus able to walk barefoot across the already emplaced deposits and escape the subsequent PDCs. The rapid cooling of the deposits was probably due to both their thinness and heat dissipation due to condensation of water vapour released in the mixture by magma–water interaction.  相似文献   

An updated catalogue of Greek archaeomagnetic data for the last 4500 years and a directional secular variation curve     

Emanuela De Marco  Evdokia Tema  Philippe Lanos  Despina Kondopoulou 《Studia Geophysica et Geodaetica》2014,58(1):121-147

We present an updated compilation of Greek directional archaeomagnetic data for the last 4.5 millennia. The data set comprises 89 directions from archaeological artefacts and volcanic rocks. Most of the data come from the Late Bronze Age (1700-1400 BC) that is the flourishing period of the Minoan civilization in Crete, while parts of the classical (480-323 BC), Hellenistic (323-31 BC) and Roman (146 BC-330 AD) periods are also well covered. The dataset has been analysed using the Bayesian approach for curve building and a directional secular variation (SV) curve for Greece is proposed. Comparisons with regional and global model predictions show a general agreement even though some discrepancies are observed for some time intervals. The new curves together with the previously published intensity SV curve for Greece, also using the Bayesian approach, form a homogeneous set and enrich our knowledge of the full geomagnetic field vector variation in Greece during the last millennia.  相似文献   

Natural contamination by As and heavy metals in soil, their bio-accumulation and potential sources: the case of a travertine limestone quarry, Greece     

Evdokia E. Kampouroglou  Maria Economou-Eliopoulos 《Central European Journal of Geosciences》2013,5(1):174-188

The first mineralogical and geochemical investigation of the travertine limestone, soil and corresponding plants associated with the Neogene basin of Varnavas, NE Attica, revealed a significant enrichment in the metalloid As. The total concentrations of As ranged from 61 to 210 ppm in limestone and 33 to 430 ppm in the associated soil demonstrating a wide variation of values. Calcite is a common authigenic mineral within travertine limestone, forming fine uniform micritic aggregates, having As and Mg concentrations lower than detection limits of EDS analysis. Clastic dominated minerals are quartz (both fine- and coarse-grained), muscovite, clinochlore, illite, pyrite, galena, arsenides, rutile, sphene, zircon, REE-minerals and albite. Goethite and Fe-Mn-oxides occur between calcite grains. The presence of fossilized micro organisms, resembling foraminifera, in travertine limestone combined with hydrous Fe-Mn-oxides, suggests a possible marine transgression during the evolution of the basin. The As content in plants ranges from 1.1 to 28 ppm As in shoots, and 0.8 to 114 ppm As in roots. The translocation factor, which is defined as the ratio of metal concentration in the shoots to the roots, is relatively low (average 0.33%) suggesting that the internal transport of metals from the roots to shoots was restricted. The bioaccumulation factor, which is defined as the ratio of metal concentration in the plants to that in soil, exhibits a wide range from relatively low (5.2–9.0% for As, Fe, Cr, Ni and Pb), much higher (56–67% for Cu and Zn) and exceptionally high (160% for Mo). A significant correlation between the translocation factors for Fe and As may confirm that Fe-Mn oxides/hydroxides represent the major sorbing agents for As in soils. The presented data, due to As contamination in travertine limestone, soil and plants, suggest a potential environmental risk not only for that part of Greece but in general for similar depositional environments.  相似文献   

Groundwater-level forecasting under climate change scenarios using an artificial neural network trained with particle swarm optimization     

Evdokia Tapoglou  Ioannis C. Trichakis  Zoi Dokou  Ioannis K. Nikolos 《水文科学杂志》2013,58(6):1225-1239

Abstract

Artificial neural networks (ANNs) have recently been used to predict the hydraulic head in well locations. In the present work, the particle swarm optimization (PSO) algorithm was used to train a feed-forward multi-layer ANN for the simulation of hydraulic head change at an observation well in the region of Agia, Chania, Greece. Three variants of the PSO algorithm were considered, the classic one with inertia weight improvement, PSO with time varying acceleration coefficients (PSO-TVAC) and global best PSO (GLBest-PSO). The best performance was achieved by GLBest-PSO when implemented using field data from the region of interest, providing improved training results compared to the back-propagation training algorithm. The trained ANN was subsequently used for mid-term prediction of the hydraulic head, as well as for the study of three climate change scenarios. Data time series were created using a stochastic weather generator, and the scenarios were examined for the period 2010–2020.