Fluid pressure,stress field and propagation style of coalescing thrusts from the analysis of the 20 May 2012 ML 5.9 Emilia earthquake (Northern Apennines,Italy)     

Guido Ventura  Rita Di Giovambattista 《地学学报》2013,25(1):72-78

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Period and chemical evolution of SC stars     

Albert A. Zijlstra  Timothy R. Bedding  rew J. Markwick  Rita Loidl-Gautschy  Vello Tabur  Kristen D. Alexander  rew P. Jacob  László L. Kiss  Aaron Price  Mikako Matsuura  Janet A. Mattei† 《Monthly notices of the Royal Astronomical Society》2004,352(1):325-337

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Application of the Linkam TS1400XY heating stage to melt inclusion studies   总被引：1，自引：0，他引：1  

Rosario Esposito  Rita Klebesz  Omar Bartoli  Yury I. Klyukin  Daniel Moncada  Angela L. Doherty  Robert J. Bodnar 《Central European Journal of Geosciences》2012,4(2):208-218

Melt inclusions (MI) trapped in igneous phenocrysts provide one of the best tools available for characterizing magmatic processes. Some MI experience post-entrapment modifications, including crystallization of material on the walls, formation of a vapor bubble containing volatiles originally dissolved in the melt, or partial to complete crystallization of the melt. In these cases, laboratory heating may be necessary to return the MI to its original homogeneous melt state, followed by rapid quenching of the melt to produce a homogeneous glass phase, before microanalyses can be undertaken. Here we describe a series of heating experiments that have been performed on crystallized MI hosted in olivine, clinopyroxene and quartz phenocrysts, using the Linkam TS1400XY microscope heating stage. During the experiments, we have recorded the melting behaviors of the MI up to a maximum temperature of 1360°C. In most of the experiments, the MI were homogenized completely (without crystals or bubbles) and remained homogeneous during quenching to room temperature. The resulting single phase MI contained a homogeneous glass phase. These tests demonstrate the applicability of the Linkam TS1400XY microscope heating stage to homogenize and quench MI to produce homogeneous glasses that can be analyzed with various techniques such as Electron Microprobe (EMP), Secondary Ion Mass Spectrometry (SIMS), Laser ablation Inductively Coupled Plasma Mass Spectrometry (LA ICP-MS), Raman spectroscopy, FTIR spectroscopy, etc. During heating experiments, the optical quality varied greatly between samples and was a function of not only the temperature of observation, but also on the amount of matrix glass attached to the phenocryst, the presence of other MI in the sample which are connected to the outside of the crystal, and the existence of mineral inclusions in the host.  相似文献   

Seismic refraction, isotropic anisotropic seismic tomography on an ancient monument (Antonino and Faustina temple ad 141)     

Ettore Cardarelli  Rita de Nardis 《Geophysical Prospecting》2001,49(2):228-240

This paper describes the results of using geophysical techniques to investigate three columns of the Pronaos of the Antonino and Faustina temple ( AD  141) in Rome, Italy; the columns are of cipollino marble which shows alternate sequences of mica and calcite beds. We applied seismic refraction using traditional interpretation, and seismic transmission tomography. The comparison between the results of the refraction study and the 2D and 3D isotropic tomographic analyses suggested anisotropic characteristics for the marble, and this prompted us to perform a further tomographic experiment, taking into account these characteristics of the material. Assuming an elliptical model, the main directions of anisotropy were detected. Two velocity fields corresponding to the main directions of the anisotropy were measured and anomalies such as cracks and fractures were noted. The conjugate-gradient algorithm was used to invert the data. The results of the isotropic and anisotropic models were compared. The correlation between the methods highlighted the characteristics of the marble, i.e. anisotropy, depth of the weathering, fractures and small cracks. The results show that the material of the columns is in reasonable condition, with the exception of a surface area 6 cm to 15 cm deep that we estimate has been weathered for 2000 years, and that has been particularly affected by pollution in the last century.  相似文献   

Heavy metals in the Ventspils Harbour: normalization based on a multi-parameter dataset   总被引：2，自引：0，他引：2  

Bärbel Müller-Karulis  Rita Poikāne  Valdis Segliņš 《Environmental Geology》2003,43(4):445-456

Heavy metals were investigated in the sediments of the Ventspils Harbour located in north-west Latvia (eastern Baltic Sea). Sediment samples were analysed for major and trace metals by ICP-AES, supplemented by inorganic and organic carbon as well as grain-size distributions. Principal component analysis of the data resulted in two main parameter clusters associated with Ca- and Al-rich material and indicated differing behaviour of Pb, Cu, Zn, N and P. Normalization with respect to Ca and Al by least absolute values regression removed the spatial pattern of sediment metal content in the harbour. High residual concentrations at individual sites were associated with local contaminations, whereas the overall concentration pattern was governed by the transport of riverine fine material. Dilution with coarser, quartz-rich marine sediments led to a pronounced heavy metal concentration drop towards the harbour gates. High mixing was an important feature of sediment dynamics in the Ventspils Harbour, hampering contaminant source identification and sediment monitoring.  相似文献   

Refractory organic carbon in particle-size fractions of arable soils II: organic carbon in relation to mineral surface area and iron oxides in fractions <6 μm     

Rita Kiem  Ingrid Kgel-Knabner 《Organic Geochemistry》2002,33(12):434

The interaction of organic compounds with the mineral phase is considered as one stabilization mechanism for organic carbon (OC) in soils. The objective of this study is to assess the role of mineral surfaces for the long-term stabilization of OC in arable soils, with special emphasis on iron oxides. Soil samples were taken from two contrasting treatment types, i.e. fertilized plots and C-depleted plots, in long-term agroecosystem experiments. The soil organic carbon pool of the C-depleted plots is considered to show a lower contribution of labile compounds and consequently to be relatively enriched in refractory compounds compared with the fertilized counterparts. In fractions <6 μm, OC was studied in relation to total mineral surface area, surface area contributed by oxides and silicates, and the content and type of iron oxides (dithionite and oxalate extractable iron, Fe_d and Fe_o). In two sandy soils, OC contents were linearly related to total mineral surface area and the content of the two iron oxide fractions (Fe_d and Fe_o). The surface area developed by the silicates was low and thus the surface area contribution from oxides was dominant in fractions <6 μm. In contrast to the sandy soils, in a loamy soil OC was not correlated with surface area or the iron oxide content. However, the different soils agreed with respect to the behavior of C in density fractions: losses of OC occurred mainly from the light fraction (2 g cm⁻³), whereas C in the heavy fraction (>2 g cm⁻³) proved to be stable. For the sandy soils, mineral surface area appears to control the storage of OC in fine fractions. Given the dominant surface area contribution from oxides, OC storage here primarily depends on the oxides. The C-depleted plots in particular show that surface area controls the accumulation of refractory C. The interaction of organic compounds with the mineral phase, mainly with the surface of oxides, seems to be a major mechanism for the long-term stabilization of OC in these sandy soils. An interaction with minerals seems to be important for stabilizing OC also in the loamy soil, although this is not reflected by a proportional relation between OC and surface area across the fractions.  相似文献   

Biometric and Genetic Analysis of the Marine Rissoid Rissoa auriscalpium (Gastropoda, Prosobranchia) and its Ecological Implications     

Rita  Colognola  Pietro  Masturzo  Giovanni Fulvio  Russo  Mlchele  Scardi  Daniele  Vlnci Eugenio  Fresi 《Marine Ecology》1986,7(3):265-285

Abstract. Two forms of Rissoa auriscalpium were found in Posidonia oceanica beds around the Island of Ischia (Gulf of Naples). In order to investigate their taxonomical value and to quantify the discriminating features found, the radular, conchometric, genetic, and ecological features of the two forms were analyzed. Ecological observations showed that the distribution of the two forms is strongly correlated with hydrodynamic factors.  相似文献   

Climate change in the Iberian Upwelling System: a numerical study using GCM downscaling     

Ana Cordeiro Pires  Rita Nolasco  Alfredo Rocha  Alexandre M. Ramos  Jesus Dubert 《Climate Dynamics》2016,47(1-2):451-464

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The first multi-model ensemble of regional climate simulations at kilometer-scale resolution part 2: historical and future simulations of precipitation     

Pichelli  Emanuela  Coppola  Erika  Sobolowski  Stefan  Ban  Nikolina  Giorgi  Filippo  Stocchi  Paolo  Alias  Antoinette  Belu&#;i&#;  Danijel  Berthou  Segolene  Caillaud  Cecile  Cardoso  Rita M.  Chan  Steven  Christensen  Ole B&#;ssing  Dobler  Andreas  de Vries  Hylke  Goergen  Klaus  Kendon  Elizabeth J.  Keuler  Klaus  Lenderink  Geert  Lorenz  Torge  Mishra  Aditya N.  Panitz  Hans-Juergen  Sch&#;r  Christoph  Soares  Pedro M. M.  Truhetz  Heimo  Vergara-Temprado  Jesus 《Climate Dynamics》2021,56(11):3581-3602

This paper presents the first multi-model ensemble of 10-year, “convection-permitting” kilometer-scale regional climate model (RCM) scenario simulations downscaled from selected CMIP5 GCM projections for historical and end of century time slices. The technique is to first downscale the CMIP5 GCM projections to an intermediate 12–15 km resolution grid using RCMs, and then use these fields to downscale further to the kilometer scale. The aim of the paper is to provide an overview of the representation of the precipitation characteristics and their projected changes over the greater Alpine domain within a Coordinated Regional Climate Downscaling Experiment Flagship Pilot Study and the European Climate Prediction system project, tasked with investigating convective processes at the kilometer scale. An ensemble of 12 simulations performed by different research groups around Europe is analyzed. The simulations are evaluated through comparison with high resolution observations while the complementary ensemble of 12 km resolution driving models is used as a benchmark to evaluate the added value of the convection-permitting ensemble. The results show that the kilometer-scale ensemble is able to improve the representation of fine scale details of mean daily, wet-day/hour frequency, wet-day/hour intensity and heavy precipitation on a seasonal scale, reducing uncertainty over some regions. It also improves the representation of the summer diurnal cycle, showing more realistic onset and peak of convection. The kilometer-scale ensemble refines and enhances the projected patterns of change from the coarser resolution simulations and even modifies the sign of the precipitation intensity change and heavy precipitation over some regions. The convection permitting simulations also show larger changes for all indices over the diurnal cycle, also suggesting a change in the duration of convection over some regions. A larger positive change of frequency of heavy to severe precipitation is found. The results are encouraging towards the use of convection-permitting model ensembles to produce robust assessments of the local impacts of future climate change.

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Three-dimensional earthquake locations and upper crustal structure of the Sannio-Matese region (southern Italy)     

Loredana Bisio  Rita Di Giovambattista  Girolamo Milano  Claudio Chiarabba   《Tectonophysics》2004,385(1-4):121-136

The Sannio-Matese region is one of the most seismically active regions of Italy and has been struck by large historical earthquakes. At present, the area is characterized by low magnitude background seismicity and small seismic sequences following M4 main events. In this paper, we show Vp and Vp/Vs models and 3D locations for a complete set of earthquakes occurring in the period 1991–2001. We observe a significant crustal heterogeneity, with large scale east-verging high Vp fault-related-folds, stacked by the Pliocene compression. The relocated earthquakes cluster along a 70° east-dipping, NW-striking plane located at the border of the high Vp thrust units. Normal fault earthquakes related to the young and active extension occur within these high Vp zones, interpreted as high strength material. We expect large future earthquakes to occur within these high Vp zones actually characterized by low magnitude seismicity at their borders.  相似文献