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71.
72.
M. Martin J. R. R. Ritter the CALIXTO working group 《Geophysical Journal International》2005,162(2):448-460
73.
The Bolcana ore deposit (Metaliferi Mountains, western Romania) is a porphyry ore deposit with associated epithermal veins. On the basis of different parageneses, four alteration types were distinguished: potassic, phyllic, argillic and propylitic. The mineralogical and geochemical data and estimated crystallisation temperatures of alteration minerals indicate an evolution of the system from an early period of porphyry type mineralisation (Cu+Au) to a late period of low-sulphidation epithermal mineralisation (Au+base metal). To cite this article: V. Milu et al., C. R. Geoscience 335 (2003). 相似文献
74.
In this paper we apply a probabilistic methodology to map specific seismic hazard induced by the Vrancea Seismogenic Zone, which represents the uttermost earthquake danger to Romania as well as its surroundings. The procedure is especially suitable for the estimation of seismic hazard at an individual site, and seismic hazard maps can be created by applying it repeatedly to grid points covering larger areas. It allows the use of earthquake catalogues with incompletely reported historical and complete instrumental parts. When applying themethodology, special attention was given to the effect of hypocentral depth and the variation of attenuation according to azimuth. Hazard maps specifying a 10% chance of exceedance of the given peak ground acceleration value for an exposure time of 50 years were prepared for three different characteristic depths of earthquakes in the Vrancea area. These maps represent a new realistic contribution to the mitigation of the earthquake risk caused by the Vrancea Seismogenic Zone in terms of: (1) input data (consistent, reliable, and the most complete earthquake catalogue), (2) appropriate and specific attenuation relationships (considering both azimuthal and depth effects); and (3) a new and versatile methodology. 相似文献
75.
Under communism local authorities tended to be largely passive bystanders in a regional development process which emerged
through the central planning process through the spatial allocations of investment by government ministries. Attention was
given to physical planning, but comparatively little material entered the public domain on location policy and spatial priorities
generally, apart from the objective of greater equality between regions and a commitment to backward areas generally. Now
that much investment is down to private enterprise and government has become more decentralised and accountable, there is
a need for concepts and strategies to coordinate public sector investment and provide guidelines for the evaluation of private
development proposals. At the same time, there is an open competition for investment which requires communities to promote
themselves in terms of their identity and development potential. This paper offers an overview by taking two countries - Hungary
and Romania - where progress can be compared and where the focus can be placed on a common frontier which is diverting attention
from conventional regional planning to cross-border cooperation. In both contexts however, attention is given to the ways
in which planning can divert investment away from the main centres to the peripheral areas, including action to strengthen
the role of small towns and also to improve cohesion among functionally-related groups of settlements and communes.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
76.
Vladimir Yu Sokolov Friedemann Wenzel Rakesh Mohindra 《Soil Dynamics and Earthquake Engineering》2009
The earthquake risk on Romania is one of the highest in Europe, and seismic hazard for almost half of the territory of Romania is determined by the Vrancea seismic region, which is situated beneath the southern Carpathian Arc. The region is characterized by a high rate of occurrence of large earthquakes in a narrow focal volume at depth from 70 to 160 km. Besides the Vrancea area, several zones of shallow seismicity located within and outside the Romanian territory are considered as seismically dangerous. We present the results of probabilistic seismic hazard analysis, which implemented the “logic tree” approach, and which considered both the intermediate-depth and the shallow seismicity. Various available models of seismicity and ground-motion attenuation were used as the alternative variants. Seismic hazard in terms of macroseismic intensities, peak ground acceleration, and response spectra was evaluated for various return periods. Sensitivity study was performed to analyze the impact of variation of input parameters on the hazard results. The uncertainty on hazard estimates may be reduced by better understanding of parameters of the Vrancea source zone and the zones of crustal seismicity. Reduction of uncertainty associated with the ground-motion models is also very important issue for Romania. 相似文献
77.
Graham Bird Paul A. Brewer Mark G. Macklin Mihaela Serban Dan Balteanu Basarab Driga 《Journal of Geochemical Exploration》2005,86(1):26-48
The Abrud–Arieş river system, western Romania, is subject to ongoing mining activity associated with Cu, Pb and Zn ore extraction. The catchment contains what is believed to be Europe's largest unutilized Au deposit at Roşia Montană that is planned to be exploited by open-cast mining techniques. The magnitude and environmental significance of metal (Cd, Cu, Pb, and Zn) concentrations in surface water and river channel sediment have been investigated along a 140 km reach of the Rivers Abrud and Arieş and 9 tributaries affected by mining. The speciation of sediment-bound metals was established using a 4-stage sequential extraction procedure (SEP) that identified four chemical phases: (1) exchangeable, (2) Fe/Mn oxides, (3) organic matter/sulphides and (4) residual. Peak solute and sediment-bound metal concentrations were found to occur in the River Abrud downstream of the EM Bucium mine and in mining-affected tributaries, with up to 71% of sites containing sediment metal concentrations in excess of Dutch intervention values. The River Arieş was found to be much less polluted than the River Abrud, with only Cu showing concentrations above guideline values, as a consequence of porphyry Cu mineralization in the catchment. The magnitude and spatial extent of metal pollution is influenced by local physico-chemical conditions and hydrological linkages between mining and local river systems. Sediment-bound Cd and Zn were found to be predominantly associated with the exchangeable phase of the sediment (9–74% and 6–65%, respectively), whilst Fe/Mn oxides (5–76%) and organic matter/sulphides (1–45%) generally accounted for a majority of Pb and Cu partitioning, respectively. Sites of environmentally significant sediment-metal pollution were identified in the Rivers Abrud and Arieş where exchangeable metal concentrations exceeded Dutch intervention values. The implications of metal contamination in the Arieş river basin to the proposed mining development at Roşia Montana are discussed in relation to other contaminated Romanian catchments and with the EU Water Framework Directive. 相似文献
78.
A new argyrodite occurrence has been discovered in the Ro?ia Montan? ore deposit located in the South Apuseni Mountains, Romania. Argyrodite is associated with common base metal sulfides and sulfosalts (galena, sphalerite, chalcopyrite, tetrahedrite ± alabandite, pyrite, and marcasite), tellurides (hessite, altaite, sylvanite) and rare electrum grains in the Ag-rich Cârnicel vein hosted by an extracraterial phreatomagmatic breccia within the Cârnic massif. SEM and EPMA analyses revealed that this argyrodite is Te-rich and a mean Ag8.04Ge0.9Te2.07S3.77 formula was calculated. This phase could be the germaniferous equivalent of the previously-described Te-rich canfieldite. To cite this article: L. Bailly et al., C. R. Geoscience 337 (2005). 相似文献
79.
The evaluation of the vulnerability of the karst aquifer and the source in the Coteţul Dobreştilor system was performed on
the basis of geological, hydrogeological and pedological data. The methods proposed in the Final Report of COST Action 620
were used. The available field data resulted in assessing the parameters P, I and in characterizing the saturated aquifer karstic network parameter (K). The soil cover over the carbonate deposits is generally shallow and easily bypassed by the superficial flow, the protection
of the karstic aquifer and the source thus being minimal. 相似文献
80.
Olivier Féménias Tudor Berza Mihai Tatu Hervé Diot Daniel Demaiffe 《International Journal of Earth Sciences》2008,97(3):479-496
The Motru Dyke Swarm intrudes the Precambrian Danubian basement of the Southern Carpathians (Romania). It is a marker of a
sub-volcanic event that occurred during the early Palaeozoic (Cambrian to Ordovician). The geographical distribution of dykes
on a ∼2,000 km2 area is heterogeneous; several areas of high dyke density have been the subject of a detailed petrological and geochemical
study. Taken altogether, the 150 samples define a single complete magmatic series, from basaltic andesite to rhyolite. Whole-rock
major element variations show a medium- to high-K, calc-alkaline magmatic suite. The compositional variations and the general
decrease of trace element contents (both compatible and incompatible, including REEs) from basaltic andesite to rhyolite are
consistent with 1) the fractionation of the observed phenocryst assemblages, Ca-amphibole (Ti-pargasite to magnesiohornblende)
followed by intermediate plagioclase, clinopyroxene and accessory biotite and quartz and 2) the absence of lower and/or upper
crustal contamination. Trace elements diagrams display typical arc patterns (LILE, Pb and LREE enrichment and relative depletion
in Nb-Ta, Zr-Hf and Ti). The Th/U, Nb/Ta and Zr/Hf ratios are constant and close to the mantle values throughout the whole
series, which argues that the parental magma was generated from a single and homogeneous enriched lithospheric mantle source.
The field regional evidence implies that melting occurred during a late- to post-orogenic period of lithospheric extension,
and thus took place quite lately after the cessation of Pan-African subduction. 相似文献