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31.
Vincenza Guarino Rogério Guitarrari Azzone Pietro Brotzu Celso de Barros Gomes Leone Melluso Lucio Morbidelli Excelso Ruberti Colombo Celso Gaeta Tassinari Mauro Brilli 《Mineralogy and Petrology》2012,104(1-2):43-61
The Ipanema alkaline-carbonatitic complex is part of the Meso-Cenozoic alkaline magmatism located within the southeastern part of the Brazilian Platform. Drill-core and field sampling have indicated the occurrence of glimmerites, with subordinate shonkinites (mela-syenites), clinopyroxene-bearing glimmerites, diorites and syenites. The glimmerites are cross-cut by lamprophyric dykes and calciocarbonatites. Fenitization has deeply affected the country rocks, originating dioritic and syenitic rocks. The Ipanema rocks show a distinct potassic affinity. The initial Sr-Nd- isotopic composition of the Ipanema rocks (87Sr/86Sr?=?0.70661–0.70754 and 143Nd/144Nd?=?0.51169–0.51181) is similar to that of tholeiitic and potassium-rich-alkaline rocks of the Eastern Paraguay. Stable isotope data for the Ipanema calciocarbonatite suggest interaction with fluids at temperatures typical of hydrothermal stages, as hypothesized for other carbonatite complexes from southeastern Brazil. The chemical differences between the lamprophyre, glimmerites, carbonatites, apatitites and magnetitites, and the absence of marked REE enrichment in the evolved lithologies, all indicate that fractional crystallization and accumulus of liquidus phases in a magma reservoir, likely coupled with liquid immiscibility processes, may have played an important role in the genesis of the Ipanema rocks. 相似文献
32.
33.
Ensemble smoothing of land subsidence measurements for reservoir geomechanical characterization 下载免费PDF全文
Domenico Baù Massimiliano Ferronato Giuseppe Gambolati Pietro Teatini Ayman Alzraiee 《国际地质力学数值与分析法杂志》2015,39(2):207-228
Geomechanical models are often used to predict the impact on land surface of fluid withdrawal from deep reservoirs, as well as investigating measures for mitigation. The ability to accurately simulate surface displacements, however, is often impaired by limited information on the geomechanical parameters characterizing the geological formations of interest. In this study, we employ an ensemble smoother, a data assimilation algorithm, to provide improved estimates of reservoir parameters through assimilation of measurements of both horizontal and vertical surface displacement into geomechanical model results. The method leverages the demonstrated potential of remote sensing techniques developed in the last decade to provide accurate displacement data for large areas of the land surface. For evaluation purposes, the methodology is applied to the case of a disk‐shaped reservoir embedded in a homogeneous, isotropic, and linearly elastic half space, subject to a uniform change in fluid pressure. Multiple sources of uncertainty are investigated, including the radius, R, the thickness, h, and the depth, c, of the reservoir; the pore pressure change, Δp; porous medium's vertical uniaxial compressibility, cM, and Poisson's ratio, ν, and the ratio, s, between the compressibilities of the medium during loading and unloading cycles. Results from all simulations show that the ensemble smoother has the capability to effectively reduce the uncertainty associated with those parameters to which the variability and the spatial distribution of land surface displacements are most sensitive, namely, R, c, cM, and s. These analyses demonstrate that the estimation of these parameters values depends on the number of measurements assimilated and the error assigned to the measurement values. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
34.
Pietro Mosca Riccardo Polino Sergio Rogledi Massimo Rossi 《International Journal of Earth Sciences》2010,99(4):833-849
Alps and Apennines are juxtaposed within an approximately 100 km-wide area covered by the Upper Eocene to Miocene successions
of the Tertiary Piedmont Basin. The Upper Eocene–Oligocene evolution of this area was characterized to the north and west
by the propagation of the SE-verging Southalpine thrust-fold belt that can be traced from the Po Plain subsurface until the
Torino Hill-Saluzzese area, and to the south by a high-angle, broadly E–W oriented megashear zone that led to the juxtaposition
of different crustal levels and controlled the development of a mosaic of partly independent sub-basins. Since the latest
Oligocene the N-verging Apenninic tectonics prevailed in the collisional system and the Tertiary Piedmont Basin evolved as
a wide thrust-top basin, bounded to the north by the N-verging Monferrato arc and characterized by a tectono-sedimentary evolution
recording changes of subsidence and shift of depocentres in relation to crustal structures. 相似文献
35.
Franco Mantovani Francisco Javier Gracia Pietro Domenico de Cosmo Andrea Suma 《Landslides》2010,7(1):69-74
This paper presents the preliminary results of a geomorphological survey of the Olvera area (Cadiz province, Betic Ranges,
Spain) and the use of the Geographic Information System (GIS) Open Source (OS) software plus Database Management System (DBMS)
for making available and distributing the landslide data over the Web. In the geomorphologic survey, different landforms have
been identified in the area, including structural, anthropogenic, fluvial, karst, and slope forms. In particular, the majority
of the slope forms are complex (from topple to rotational slides and falls), but there are also minor forms like debris flows
and mudslides. To manage geomorphological data, an Open Source GIS was used, which contained the following components: QuantumGIS,
System for Automated Geoscientific Analyses (SAGA), GIS and Geographic Resources Analysis Support System (GRASS), GIS for
Digital Elevation Model (DEM) generation. A key aim was to make the project-derived data available over the Web. This was
achieved using MapServer which allows for the representation of the derived geospatial data with pMapper providing the graphical
Web interface. Our study highlights the process dynamics of run-off erosion in Olvera derived through the use of advanced
computer-based mapping tools. The resulting map products and interpretations are available via the Internet. To date, derivative
maps have been produced to improve maintenance of roads and transport and of the construction of new infrastructure. 相似文献
36.
Antonio Bucci Gino Naclerio Vincenzo Allocca Pietro Celico Fulvio Celico 《水文研究》2011,25(12):1866-1873
The Ischia hydrothermal system was analysed through hydrogeological and microbial community investigations. Mesophilic communities were detected in two cold springs, suggesting a negligible influence of thermal circuits in freshwater sub‐systems which are mainly or only fed by local precipitations. Thermophilic and extremely thermophilic bacteria were detected in two wells, according to higher water temperatures (61 and 85 °C), even if the two communities show significant differences. In one well, thermophilic and extremely thermophilic bacteria are associated with strains belonging to ε‐Proteobacteria isolated in different sulphur‐rich carbonate environments. This association suggests a greater influence on ascending hot fluids that interact with the carbonate basement of volcanic rocks. In the other well, thermophilic and extremely thermophilic bacteria are associated with strains isolated in cold hypersaline environments or in aquatic habitats where terrestrial and marine components are coupled. This association supports the fact that seawater intrusion can affect this part of Ischia, according to results of hydrogeological and geochemical surveys. Differences in groundwater temperature and bacterial communities are probably mainly due to differences in permeability between volcanic rocks and differences in hydrogeologic behaviour between faults in the upper carbonate basement, above the deep magma chamber, that influence relationships between ascending hot fluids and local recharge. This study contributes to discussion of the reliability of the actual behaviour models of the Ischia system, based on the results of geochemical and isotopic investigations, and, in a wider context, it shows that microbial community investigations may be a valuable supplementary tool for analysing hydrothermal system behaviour. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
37.
A. Bottari E. Carapezza M. Carapezza P. Carveni F. Cefali E. Lo Giudice C. Pandolfo 《Journal of Geodynamics》1986,5(3-4)
The original historical data from surveys of the damage caused by the great Calabro-Messina earthquake are analyzed in detail. This analysis allows the macroseismic field to be reconstructed in a way more compatible with a modern scientific viewpoint, laying maximum importance on indications supplied by the MSK intensity scale.A geometrical model of the focus has been worked out, adopting in part the schemes proposed by Shebalin. This model, together with the macroseismic field parameters, is correlated with the regional structural parameters. Finally, in their quest for better knowledge of the regional seismotectonic pattern, the authors search for evidence of geodynamic consistency by analyzing a spatio-temporal period in the neighborhood of the event. 相似文献
38.
Adjustments in channel morphology due to land‐use changes and check dam installation in mountain torrents of Calabria (southern Italy) 下载免费PDF全文
Diego Fortugno Carolina Boix‐Fayos Giuseppe Bombino Pietro Denisi Juan Manuel Quiñonero Rubio Vincenzo Tamburino Demetrio Antonio Zema 《地球表面变化过程与地形》2017,42(14):2469-2483
In Mediterranean semi‐arid conditions, the availability of studies monitoring channel adjustments as a response to reforestation and check dams over representative observation periods, could help develop new management strategies. This investigation is an integrated approach assessing the adjustments of channel morphology in a typical torrent of southern Italy after land‐use changes and check dam construction across a period of about 60 years. A statistical analysis of historical rainfall records, an analysis of land‐use changes in the catchment area and a geomorphological mapping of channel adjustments were carried out and combined with field surveys of bed surface grain‐size over a 5‐km reach including 14 check dams. The analysis of the historical rainfall records showed a slight decrease in the amount and erosivity of precipitation. Mapping of land‐use changes highlighted a general increase of vegetal coverage on the slopes adjacent to the monitored reaches. Together with the check dam network installation, this increase could have induced a reduction in water and sediment supply. The different erosional and depositional forms and adjustments showed a general narrowing between consecutive check dams together with local modifications detected upstream (bed aggradation and cross‐section expansion together with low‐flow realignments) and downstream (local incision) of the installed check dams. Changes in the torrent bends were also detected as a response to erosional and depositional processes with different intensities. The study highlighted: the efficiency of check dams against the disrupting power of intense floods by stabilizing the active channel and the influence of reforestation in increasing hillslope protection from erosion and disconnectivity of water and sediment flows towards the active channel. Only slight management interventions (for instance, the conversion of the existing check dams into open structures) are suggested, in order to mobilize the residual sediment avoiding further generalized incision of the active channel and coast line erosion. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
39.
Luigi Tosi Pietro Teatini Laura Carbognin Jane Frankenfield 《Environmental Geology》2007,52(5):889-898
The paper deals with the implementation of a levelling and Global Positioning System (GPS) network to control land subsidence
in the coastal area north of the Venice Lagoon. About 480 km of levelling lines with 527 benchmarks, 45 of which suited for
Differential GPS measurements, were established in 2004. A complete survey of the net was carried out in 2004 soon after its
establishment. The 2004 records have been compared with previous scattered data obtained by the use of levelling surveys,
DGPS and SAR interferometry. The results show a trend in land settlement that increases from the lagoon margin to the north
and jeopardize the Venice coastland. Groundwater withdrawals for domestic, agricultural, and health spas uses, peat oxidation
of reclaimed marshlands for farming, natural consolidation of the Holocene deposits, and tectonics of the pre-Quaternary basement
are the causes of land subsidence in the study area. Since most of the area lies below the mean sea level and on account of
the expected sea level rise due to global change, a detailed monitoring of land displacements in the near future will be of
paramount importance to plan necessary works for coastland protection. 相似文献
40.
Modeling regional initiation of rainfall-induced shallow landslides in the eastern Umbria Region of central Italy 总被引:3,自引:6,他引:3
Diana Salciarini Jonathan W. Godt William Z. Savage Pietro Conversini Rex L. Baum John A. Michael 《Landslides》2006,3(3):181-194
We model the rainfall-induced initiation of shallow landslides over a broad region using a deterministic approach, the Transient Rainfall Infiltration and Grid-based Slope-stability (TRIGRS) model that couples an infinite-slope stability analysis with a one-dimensional analytical solution for transient pore pressure response to rainfall infiltration. This model permits the evaluation of regional shallow landslide susceptibility in a Geographic Information System framework, and we use it to analyze susceptibility to shallow landslides in an area in the eastern Umbria Region of central Italy. As shown on a landslide inventory map produced by the Italian National Research Council, the area has been affected in the past by shallow landslides, many of which have transformed into debris flows. Input data for the TRIGRS model include time-varying rainfall, topographic slope, colluvial thickness, initial water table depth, and material strength and hydraulic properties. Because of a paucity of input data, we focus on parametric analyses to calibrate and test the model and show the effect of variation in material properties and initial water table conditions on the distribution of simulated instability in the study area in response to realistic rainfall. Comparing the results with the shallow landslide inventory map, we find more than 80% agreement between predicted shallow landslide susceptibility and the inventory, despite the paucity of input data. 相似文献