Search results for "Geology"
showing 10 items of 6012 documents
Cueva de El Toro (Antequera, Malaga-Spain): a Neolithic stockbreeding community in the Andalusian region, between the 6th and 3th millennia BC
2004
The occupation evidence shown by the cave El Toro, is that of a unique stockbreeding community in the Andalusian region. The calibrated dates for this occupation period go from the second quarter of the sixth millennium up to the second millennium BP. There is also evidence of occasional occupation throughout later millennia up to the Hispano-Muslim period. The nature of thisoccupation is determined by the close link between the cave and the community which occupied it, both continuously and periodically. Throughout the occupation levels, the community's skillful control of technical processesand its remarkable knowledge on how to transform local primary resources, have shown that this comm…
Sedimentology and vertebrate fossils of the Frasnian Ogre Formation, Gurova outcrops, eastern Latvia
2020
Combined sedimentological and palaeontological study of the siliciclastic sequence of the Ogre Formation in the easternmost area of its distribution in Latvia was aimed at the facies analysis of the deposits and at detailed observation of the taxonomical and taphonomical peculiarities of the fossil vertebrate assemblage. Two facies associations, tidally-influenced fluvial channels and lateral tidal bars, have been identified in exposures along the Gurova River. Sedimentological evidences suggest that the studied deposits were formed in the fluvial environment with strong tidal influence. The sedimentary concentrations of vertebrate remains, dominated by the antiarch Bothriolepis maxima, por…
Depositional environment of the tidally-dominated transgressive succession: Rēzekne and Pärnu regional stages, Baltic devonian basin
2013
Disertācijas pētijumu tēma ir veltīta Rēzeknes un Pernavas reģionālo stāvu nogulumu fāciju pētījumiem un to uzkrāšanās vides rekonstrukcijai Baltijā. Agrākie pētījumi šajā devona klastisko nogulumu slāņkopas daļā tika veltīti galvenokārt litoloģiskiem, mineraloģiskiem un stratigrāfiskiem pētījumiem, kā arī nogulumu sastāva pētījumiem baseina austrumdaļā. Detalizēti pētījumi ar mērķi rekonstruēt kopējo baseina attīstību līdz sim netika veikti. Tādēļ, Rēzeknes un Pērnavas reģionalo stavu slāņkopas veidošanas apstākļi bija maz zināmi, kā arī diskutabli. Pēdējo desmit gadu laikā fāciju analīzes loma seno baseinu rekonstrukcijās tika plaši pielietota vidus un augšdevona klastiskās slāņkopas pētī…
The Contribution of Electrical Resistivity Measurements to the Analysis of Landslide Events
2005
In order to gain insight into the study of natural avalanches dynamics, we illustrate a statistical model based on a dissipative dynamical variable associated to a position dependent factor of safety field. This model, as experimentally demonstrated, is able to reproduce the complex structure of landslide events, such as power-law distributions. In this paper, we introduce an explicit dependence of the safety factor on the electrical resistivity to simulate landslide events in pyroclastic soils. An application of the model to data acquired in a test area characterized by flowslide events (Monte Albino, Campania Region - South Italy) bear witness the relevant role played by the resistivity m…
Stability of Embankments Resting on Foundation Soils with A Weak Layer
2021
The presence of weak layers in geotechnical systems, including soil or rock masses, both natural and man-made, is more frequent than is normally believed. Weak layers can affect both failure mechanisms, in drained and in undrained conditions, as well as in static and seismic conditions, and the safety factor. In the present study, conducted numerically using the finite-element method (FEM) Plaxis 2D code, the influence of a horizontal thin weak layer on stress and strain distribution, on failure mechanisms and on the overall stability of an embankment was evaluated. The results obtained prove that when the weak layer is located at a significant depth from the foundation plane, the failure m…
Toward the Development of Load Transfer Efficiency Evaluation of Rigid Pavements by a Rolling Wheel Deflectometer
2020
The jointed rigid pavement is currently evaluated by the Falling weight deflectometer which is rather slow for the testing of the jointed pavements. Continuous nondestructive evaluation of rigid pavements with a rolling wheel deflectometer can be used to measure the load transfer and is investigated. Load transfer is an important indicator of the rigid pavement&rsquo
The importance of fracture-healing on the deformation of fluid-filled layered systems
2014
International audience; Understanding the fracturingehealingerefracturing cycle is a fundamental part of studying the deformation dynamics and the permeability evolution of rock systems. Previous studies, however, have not examined the influence of healing i.e. fracture-closure through vein formation and the mechanical properties of the " healed " fractures (veins) on the rock deformation. We present results from a two-dimensional coupled hydro-mechanical model which simulates large time and spatial scale dynamic fracturing and healing of a porous medium under the influence of gravity, tectonic stretching and elevated fluid pressures. Our results show that healing decreases the local porosi…
Preliminary report on the microvertebrate faunal remains from the Late Triassic locality at Krasiejów, SW Poland
2019
Fossil vertebrate remains from the Keuper unit in the vicinity of the village of Krasiejów have been analyzed for almost two decades. However, the main goal of these works was focused mainly on large vertebrates. Here the authors present the first description of microvertebrate fossils from that site. The collection of around 5,000 specimens is mainly comprised of teeth and scales. The most numerous remains belong to osteichthyans: dipnoans (Ptychoceratodus and cf. Arganodus), palaeoniscids, semionotids, redfieldiids and chondrichthyans, such as Lonchidion sp., which is the first indisputable record of that genus in the Upper Triassic of Poland and the first shark at the Krasiejów locality.…
Degradation of Amino-(3-methoxyphenyl)methanephosphonic Acid by Alternaria sp
2002
Alternaria sp. isolated from the surface of carrot ( Daucus carota ) seeds appeared to be able to degrade amino-(4-methoxyphenyl)-methanephosphonic acid using it as a sole source of carbon, nitrogen, and phosphorus for growth.
Os, Sr, Nd, Pb, O isotope and trace element data from the Ferrar flood basalts, antarctica: evidence for an enriched subcontinental lithospheric sour…
1996
Os, Sr, Nd, Pb and O isotopes and trace element data are reported for basaltic andesite and andesite whole rocks and, in part, for selected mineral separates from the Jurassic Ferrar flood basalt province. Radiogenic Sr (> 0.709), unradiogenic Nd (εNd= −3 to −5), and radiogenic Pb isotopes, as well as low Nb/La ratios of 0.4 – 0.6 and Nb/La ratios between 0.45 and 0.6 are found for all rocks including our most primitive sample (Mg# = 71.9). This indicates involvement of either continental crust or enriched lithospheric mantle in magma genesis. 187Re/188Os correlates strongly with 187Os/188Os, with an age of 172 ± 5 Ma, in agreement with published Arsingle bondAr data. Initial 187Os/188Os of…