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排序方式: 共有543条查询结果,搜索用时 15 毫秒
111.
112.
Donaldo Mauricio Bran Jorge Gabriel Lozano Dario Civile Emanuele Lodolo María E. Cerredo Alejandro Tassone Luca Baradello Maurizio Grossi Juan Vilas 《第四纪科学杂志》2020,35(3):396-409
Lago Roca/Acigami is a “fjord-type” lake located in the southernmost part of South America, in the proximity of the Beagle Channel. A high-resolution seismic survey was carried out to analyse the seismic stratigraphy of the lake and to shed some light on the post-Last Glacial Maximum history of the area. Six seismic units were recognised, and their nature and depositional context were interpreted using seismic stratigraphy and acoustic facies analysis. A buried large ridge was identified within the glacial unit (SU1), interpreted as a frontal moraine that indicates a stabilisation phase. After retreat of the glacier from the basin, the trough was flooded by meltwater and a lake developed (SU2). The seismic facies, from bottom to top, depict a transition from ice-contact (SU2; SU3) to ice-distal proglacial conditions (SU4). A thick draping unit (SU5) marks a marine transgressive event and the instauration of a fjord environment in the basin. The marine transgression was a rapid event preceded by a fall in the lake level that caused an erosional unconformity. During the fjord phase the sedimentation remained controlled by meltwater discharge. Sea level fall, and subsequent disconnection from the Beagle Channel was accompanied by a progradation of the glaciofluvial deltaic sediments and the occurrence of several mass-wasting deposits (SU6). © 2019 John Wiley & Sons, Ltd. 相似文献
113.
List of papers from other journals 相似文献
114.
Rocky Dunlap Leo Mark Spencer Rugaber V. Balaji Julien Chastang Luca Cinquini Cecelia DeLuca Don Middleton Sylvia Murphy 《Earth Science Informatics》2008,1(3-4):131-149
The Earth System Curator is a National Science Foundation sponsored project developing a metadata formalism for describing the digital resources used in climate simulations. The primary motivating observation of the project is that a simulation/model’s source code plus the configuration parameters required for a model run are a compact representation of the dataset generated when the model is executed. The end goal of the project is a convergence of models and data where both resources are accessed uniformly from a single registry. In this paper we review the current metadata landscape of the climate modeling community, present our work on developing a metadata formalism for describing climate models, and reflect on technical challenges we have faced that require new research in the area of Earth Science Informatics. 相似文献
115.
Be exposure ages of a rock avalanche and a late glacial moraine in Alta Valtellina, Italian Alps 总被引:1,自引:0,他引:1
Anne Hormes Susan Ivy-Ochs Peter W. Kubik Luca Ferreli Alessandro Maria Michetti 《Quaternary International》2008,190(1):136
A rock avalanche deposit was investigated in order to understand the chronological evolution of geological hazards and to evaluate the interaction of the triggering geodynamic processes in the valley Val Viola, Italian Alps. The deposit is situated west of the Alpe Dosdé, in a permafrost area with deep-seated gravitational deformations (DSGD) along a tectonic line. Based on its geomorphologic context, the rock avalanche was first interpreted as a result of slope stress release without exact timing. This hypothesis was tested by measuring the 10Be exposure date of quartz from one boulder from the rock avalanche. The age of 7430±460 years places the event in the early Holocene. The timing of the last deglaciation was constrained using the inner late glacial moraine of a moraine doublet in the valley Alpe Dosdé situated at an altitude between 2140 and 2120 m a.s.l. west of the rock avalanche. The 10Be concentrations of quartz yield minimum exposure ages of 11,480±670 and 10,850±820 years. Different proposals for potential triggering factors of the rock avalanche include (a) melting of the local valley glacier and slope stress release in the Val Viola, likely to play a minor role as trigger, because of the time delay between the deglaciation and the rock avalanche event. More likely are (b) enhanced crustal seismicity induced by post-glacial regional isostatic glacial rebound coupled with tectonic stress or/and (c) climate conditions with higher temperatures around 7430±460 years, resulting in an upwards movement of the permafrost limit and destabilization of the rock walls. 相似文献
116.
Pilario Costagliola Marco Benvenuti Laura Chiarantini Sara Bianchi Francesco Di Benedetto Mario Paolieri Luca Rossato 《Applied Geochemistry》2008
A significant As anomaly has been reported in the literature for stream sediments and unlithified Quaternary deposits of the Pecora River valley in Southern Tuscany, extending from the “Colline Metallifere” pyrite-base metals district to the Tyrrhenian Sea. The As anomaly spreads over several square kilometers around a core that exceeds 500 ppm. Several source contributions (from natural to anthropogenic) have been invoked to explain the observed As distribution in the Pecora Valley, including the metal-working industry which was active in this area, particularly in Etrusco-Roman times and in the Middle Ages. In order to evaluate the contribution of ancient mining and metallurgical activities in the Pecora Valley to elevated As concentrations in the environment, a detailed mineralogical and geochemical survey of metallurgical slags and smelted ore minerals was undertaken from six different sites through the Pecora Valley: Poggio Butelli (Etrusco-Roman iron slags); Sata Creek, Arialla, Marsiliana, Forra and Cascata sites (all Medieval base metals slags). The As content of Etrusco-Roman slags is relatively low (few tens of ppm), whereas Medieval slags show variable, but higher amounts of base metals (±Ag) (ranging from tens to tens of thousands ppm) and As (up to 267 ppm, with average contents of about 40 ppm). Arsenic is mostly partitioned in sulfides disseminated through the glassy groundmass rather than in solid solution with the glassy matrix. Remnants of the ore used for base metal and Ag smelting during the Middle Ages had the highest As contents (up to about 1000 ppm). 相似文献
117.
G.?DuveillerEmail authorView authors OrcID profile M.?Donatelli D.?Fumagalli A.?Zucchini R.?Nelson B.?Baruth 《Theoretical and Applied Climatology》2017,127(3-4):573-585
Coupled atmosphere-ocean general circulation models (GCMs) simulate different realizations of possible future climates at global scale under contrasting scenarios of land-use and greenhouse gas emissions. Such data require several additional processing steps before it can be used to drive impact models. Spatial downscaling, typically by regional climate models (RCM), and bias-correction are two such steps that have already been addressed for Europe. Yet, the errors in resulting daily meteorological variables may be too large for specific model applications. Crop simulation models are particularly sensitive to these inconsistencies and thus require further processing of GCM-RCM outputs. Moreover, crop models are often run in a stochastic manner by using various plausible weather time series (often generated using stochastic weather generators) to represent climate time scale for a period of interest (e.g. 2000 ± 15 years), while GCM simulations typically provide a single time series for a given emission scenario. To inform agricultural policy-making, data on near- and medium-term decadal time scale is mostly requested, e.g. 2020 or 2030. Taking a sample of multiple years from these unique time series to represent time horizons in the near future is particularly problematic because selecting overlapping years may lead to spurious trends, creating artefacts in the results of the impact model simulations. This paper presents a database of consolidated and coherent future daily weather data for Europe that addresses these problems. Input data consist of daily temperature and precipitation from three dynamically downscaled and bias-corrected regional climate simulations of the IPCC A1B emission scenario created within the ENSEMBLES project. Solar radiation is estimated from temperature based on an auto-calibration procedure. Wind speed and relative air humidity are collected from historical series. From these variables, reference evapotranspiration and vapour pressure deficit are estimated ensuring consistency within daily records. The weather generator ClimGen is then used to create 30 synthetic years of all variables to characterize the time horizons of 2000, 2020 and 2030, which can readily be used for crop modelling studies. 相似文献
118.
Francesco Di Benedetto Ilaria Bencistà Francesco D’Acapito Silvia Frizzera Andrea Caneschi Massimo Innocenti Alessandro Lavacchi Giordano Montegrossi Werner Oberhauser Maurizio Romanelli Herbert Dittrich Luca A. Pardi Gerold Tippelt Georg Amthauer 《Physics and Chemistry of Minerals》2016,43(8):535-544
The successful synthesis of nanoparticles of Fe-bearing kuramite, (Cu,Fe)3SnS4, is reported in this study. Nanocrystalline powders were obtained through a mild, environmentally friendly and scalable solvothermal approach, in a single run. The sample was the object of a multidisciplinary investigation, including X-ray diffraction and absorption, scanning electron microscopy and microanalysis, electron paramagnetic resonance, diffuse reflectance and Mössbauer spectroscopy as well as SQUID magnetometry. The nanoparticles consist of pure Fe-bearing kuramite, exhibiting tetragonal structure. The valence state of the metal cations was assessed to be Cu+, Sn4+ and Fe3+. The material presents a band gap value of 1.6 eV, which is fully compatible with solar cell applications. The uptake of Fe by nanokuramite opens a compositional field where the physical properties can be tuned. We thus foster the application of Fe-bearing nanokuramite for photovoltaics and energy storage purposes. 相似文献
119.
Luca Bindi Ekaterina A. Sirotkina Andrey V. Bobrov Fabrizio Nestola Tetsuo Irifune 《Physics and Chemistry of Minerals》2016,43(2):103-110
The crystal structure and chemical composition of a crystal of (Mg14?x Cr x )(Si5?x Cr x )O24 (x ≈ 0.30) anhydrous Phase B (Anh-B) synthesized in the model system MgCr2O4–Mg2SiO4 at 12 GPa and 1600 °C have been investigated. The compound was found to be orthorhombic, space group Pmcb, with lattice parameters a = 5.900(1), b = 14.218(2), c = 10.029(2) Å, V = 841.3(2) Å3 and Z = 2. The structure was refined to R 1 = 0.065 using 1492 independent reflections. Chromium was found to substitute for both Mg at the M3 site (with a mean bond distance of 2.145 Å) and Si at the octahedral Si1 site (mean bond distance: 1.856 Å), according to the reaction Mg2+ + Si4+ = 2Cr3+. Such substitutions cause a reduction in the volume of the M3 site and an increase in the volume of the Si-dominant octahedron with respect to the values typically observed for pure Anh-B and Fe2+-bearing Anh-B. Taking into account that Cr3+ is not expected to be Jahn–Teller active, it appears that both the Cr3+–for–Mg and Cr3+–for–Si substitutions in the Anh-B structure decrease the distortion of the octahedra. Electron microprobe analysis gave the Mg13.66(8)Si4.70(6)Cr0.62(4)O24 stoichiometry for the studied phase. The successful synthesis of this phase provides new information for the possible mineral assemblages occurring in the Earth’s deep upper mantle and shed new light on the so-called X discontinuity that has been observed at 275–345 km depth in several subcontinental and subduction zone environments. 相似文献
120.