Instrumental seismological data since 1900 for northeastern Italy     

Claudio Margottini  Guido Martini  Dario Slejko 《地震工程与结构动力学》1993,22(12):1017-1030

Statistical analyses on a catalogue of instrumental data for earthquakes in northeastern Italy since 1900 are presented. The different types of magnitude, which are the main parameters under study, have been evaluated so as to be as homogeneous as possible. Comparisons of the different magnitude values show linear dependence, at least in the medium magnitude range represented by the available data set. Correlations between the magnitude most significant for this region and chosen macroseismic data indicate a methodology for assessing the macroseismic magnitude of historical earthquakes which seems to be stable.  相似文献   

Stratiform gold mineralization in palaeosol and ironstone of early Proterozoic age,Transvaal Sequence,South Africa     

J. E. J. Martini 《Mineralium Deposita》1986,21(4):306-312

An early Proterozoic palaeosol, developed on basalt and the basal part of an overlying transgressive marine sedimentary sequence, contains pyrite which is auriferous in places. The mineralization is stratiform and continuous over a distance of several hundred kilometres. Although this mineralization can be explained by a number of genetical models the author concluded that the mineralization took place during pedogenesis and/or diagenesis. Gold is considered to have been leached from the basalt and from the B horizon of the palaeosol by sulphide-rich groundwater and was then precipitated by the effect of the lowering of the HS^– activity. The latter is thought to have been caused by atmospheric oxidation and by reaction with Fe-rich leachate from the A horizon, and pyritization of pre-existing iron oxide minerals may also have contributed. It is concluded that a pedogenic gold protore may explain the origin of at least some of the gold of the Witwatersrand type of deposit.  相似文献   

Seasonal changes of the profundal macrobenthic community in a polluted lake     

Marcello Bazzanti  Marco Seminara 《Aquatic Sciences - Research Across Boundaries》1985,47(1):57-63

Late summer and winter structures of the profundal macrobenthos in a polluted lake (Lake Nemi, Central Italy) were compared to verify the relative differences in the faunal structure and the magnitude of the winter recovery of this community. Densities of Oligochaetes and Chironomids did not vary significantly from summer to winter, the latter not showing any recolonization of the profundal zone. Structure and diversity of the total fauna, and Oligochaete/Chironomid ratio were very similar in the two periods. Our results suggest that in a severely polluted lake, with a strong and lasting oxygen deficit in the hypolimnic zone, a lack of recovery of profundal macrobenthos may be expected in improved environmental winter conditions.  相似文献   

Contents volume 40     

W.A. King  I.P. Martini 《Sedimentary Geology》1984,40(4):295-320

The Attawapiskat River is one of the major low-gradient rivers which cross the flat wetlands of the Hudson Bay Lowland. It has a nival regime leading to strong, short-duration spring floods during which considerable amount of sediment is carried. For the remainder of the year only organic matter is transported in solution and suspension. The land is isostatically rebounding after the Pleistocene glaciations. The river downcuts through the softer Holocene estuarine basal clays and the Pleistocene tills, to the Paleozoic carbonate bedrock. The river develops an anastomosing pattern in the lower reaches and it acquires an irregular meandering character inland. It does not construct a significantly thick delta as the river-borne sediments are dispersed along the coasts by tides, longshore currents and ice rafting. The river is subjected to frequent ice jams in its lower reaches as warmer southern waters flow toward the still frozen mouth and sea. During the jams, secondary channels become active, floodings develop and sedimentation occurs on the levees. Ice scours and ice-rafted materials affect the river banks greatly.The principal sedimentary environments within the river consist of: (1) erosional shoals covered by boulder and pebble lags over till: (2) sorted coarse to medium-sized sands in junction bars downstream from islands; these sands frequently develop gas bubbles, and they contain characteristic fining-upward sequences from boulder pavements at the base, grading up into rippled sand with abundant organic matter, grading up into laminated silt and sand and organic matter; (3) secondary channels, which develop thin silty and clay drapes on eroded hard substratum and are filled eventually by thick peats; and (4) river banks which show well-developed regressive sequences from Pleistocene tills at the base, overlain by estuarine sparsely fossiliferous clays, capped by thin conglomeratic units with abundant reworked Macoma balthica shells, grading upward into upper tidal flat sand, irregularly laminated sand and silt of marshes, and regular interbedding of sand, silt and organic layers of the levees at the top.  相似文献   

Phytoliths at DSDP Site 591 in the southwest Pacific and the aridification of Australia     

Dr. S. Locker  Prof. Dr. E. Martini 《International Journal of Earth Sciences》1989,78(3):1165-1172

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Deformation between 1989 and 1997 at Piton de la Fournaise volcano retrieved from correlation of panchromatic airborne images     

Marcello de Michele  Pierre Briole 《Geophysical Journal International》2007,169(1):357-364

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Observing water-level variations from space-borne high-resolution Synthetic Aperture Radar (SAR) image correlation     

Daniel Raucoules  Gonéri Le Cozannet  Marcello de Michele  Sylvain Capo 《国际地球制图》2018,33(9):977-987

The potential of correlating high-resolution Synthetic Aperture Radar images to estimate local water-level variations is analysed based on observing the motions of floating structures. By computing range and azimuth offsets on a COSMO-SkyMed multi-temporal data-set in an area of the French Atlantic Coast, displacement signatures were detected in several harbours of the region. They can be associated with specific floating structures, whose vertical motion is mostly driven by tides. Although the image resolution is not the best achievable for the COSMO-SkyMed sensor, comparison with ground-based tide information revealed that the obtained space-borne measurements are consistent with the tide gauges to a decimetric accuracy. Even if the requirements for traditional users of tidal data are not met by the current revisit time of the COSMO-SkyMed constellation, the method proposed here provides complementary measures, which are already well aligned to requirements of users concerned with long-term sea-level variation and river or lake water stocks.  相似文献   

The environmental risk posed by small dumps of complex arsenic,antimony, nickel and cobalt sulphides     

C. Trois  A. Marcello  S. Pretti  P. Trois  G. Rossi 《Journal of Geochemical Exploration》2007

Mine waste dumps sited in the vicinity of mine workings typically consist of fragmented rock masses which in chemical terms may be defined as "complex systems", due to uncertainties in accurately simulating their behaviour, when water or aqueous solutions percolate through them. Remediation of the contamination problems created by abandoned mine dumps concerns many former mining areas from Europe to Africa. These dumps usually range in size from a few hundred thousand up to million cubic meters of rock defined as “waste” but which still contain significant amounts of potentially toxic elements. Although relatively small, they are often densely distributed in the territory impacting on surface and ground-water. This scenario is particularly applicable to the region of Sardinia, Italy, where several small dumps of uncommon sulphide minerals still exist on derelict mine sites. This paper reports on the results of a research project aimed at defining appropriate remedial measures of acid rock drainage. A dump of a Co–Ni–As–Sb complex sulphides mine was investigated and simulated in a laboratory leaching column. The column was irrigated with distilled water and a repetitive behaviour of the polluting elements concentrations in the effluents was observed for each run. Regardless of the campaign duration and the extent of the intervals between tests metal ions concentration peaks (250–50 ppm for Ni, 35–20 ppm for Co, 1.6–0.4 ppm for As, 20–15 ppm for Zn and 0.03–0.002 ppm for Sb) and acidic conditions (pH 2.5–3.5), on resumption of each irrigation, was noticed. As percolation continued, the ion concentrations decreased within the discharge limits after the replacement of only two pore volumes of the column material. This produces the conception that a sufficiently long rainfall period could remediate the polluting effects. Conception contradicted by field experiences: sporadic rainfall events, typical of the region, are not sufficient to completely leach out the metal ions. The repetitive nature of the leaching processes, both quantitatively and qualitatively, can be explained only by the activity of a microflora thriving in the rock mass even during long dry periods. Microbial tests and neutralisation campaigns confirmed this hypothesis and suggested that any effective remediation strategy must take into consideration the interaction between environmental factors with microbiological activities.  相似文献   

Vulnerability to contamination by phosphorus in a zero-order basin with a high density of pigs and a history of slurry addition: extrapolation of an index     

Rafael da Rosa Couto  Luiz Carloz Pittol Martini  Luciano Colpo Gatiboni  Paulo Belli Filho  Sérgio Roberto Martins  Cleiton Junior Ribeiro Lazzari  Vilmar Müller Júnior  Jucinei José Comin  Paul John Anthony Withers  Ricardo Bergamo Schenato  Gustavo Brunetto 《Environmental Earth Sciences》2018,77(4):144

The application of phosphorus (P)-index methodology to assess the risk of water pollution from agriculture in river basins usually takes time and expends a great amount of resources. This study adapted the P-index methodology using digital mapping of key basin risk criteria for P loss in reference areas to evaluate the wider vulnerability to P loss in a zero-order basin with an intense concentration of pigs and with a history of pig slurry additions to the soil. The P content of eleven reference areas, where ten areas have received various applications of pig slurry and one area has no history of addition, was extrapolated to a zero-order basin using principal component analysis and analysis of hierarchical groupings. Estimated loss of soil and the distance between the P source and the watercourse were mapped using satellite images and in situ evaluations. The methodology of extrapolating was well correlated with a survey of P concentrations in land runoff and provides the potential to improve land management of those areas that are most vulnerable. Principal component analysis and hierarchical clustering analysis proved to be useful tools for the separation of areas with different slurry application times. Our results suggest that the P loss risk could be reduced through the adoption of soil conservation techniques such as reduced-tillage incorporating slurry and crop residue management to provide adequate soil protection, reduce the impact of raindrops and reduce erosion risk and transport of chemical pollutants to water bodies.  相似文献   

Facies analysis of a Pliocene river‐dominated deltaic succession (Siena Basin,Italy): Implications for the formation and infilling of terminal distributary channels          下载免费PDF全文

Ivan Martini  Fabio Sandrelli 《Sedimentology》2015,62(1):234-265

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