Geochemistry and metamorphic evolution of the Pohorje Mountain eclogites from the easternmost Austroalpine basement of the Eastern Alps (Northern Slovenia)

Kyanite-rich and quartz-rich eclogites occur as lenses within amphibolite-facies quartzo-feldspathic gneisses in the Pohorje Mountains, Northern Slovenia, that form the easternmost Austroalpine basement. Major and trace elements indicate that the kyanite-rich eclogites were derived from plagioclase-rich gabbroic cumulates, whereas the quartz-rich eclogites represent more fractionated basaltic compositions. Both varieties are characterized by a LREE-depleted N-MORB type REE signature. Geothermobarometry and P-T pseudosections indicate that eclogites equilibrated at 1.8-2.5 GPa and 630-700 °C, consistently with the lack of coesite and with equilibration conditions of the chemically similar eclogites from the adjacent basement units at Koralpe and Saualpe type localities. Decompression reaction textures include (i) clinopyroxene-plagioclase intergrowths after omphacite, (ii) replacement of kyanite by corundum-plagioclase-spinel±sapphirine symplectites, (iii) breakdown of phengite to biotite-plagioclase sapphirine symplectites. The results of this study indicate that Koralpe, Saualpe and Pohorje high-pressure rocks represent former MORB-type oceanic crust that was subducted in the course of the late Cretaceous (approximately 100 Ma ago) collision between the European and the Apulian plates.     

Ultrahigh-pressure metamorphism and exhumation of garnet peridotite in Pohorje, Eastern Alps

New evidence for ultrahigh‐pressure metamorphism (UHPM) in the Eastern Alps is reported from garnet‐bearing ultramafic rocks from the Pohorje Mountains in Slovenia. The garnet peridotites are closely associated with UHP kyanite eclogites. These rocks belong to the Lower Central Austroalpine basement unit of the Eastern Alps, exposed in the proximity of the Periadriatic fault. Ultramafic rocks have experienced a complex metamorphic history. On the basis of petrochemical data, garnet peridotites could have been derived from depleted mantle rocks that were subsequently metasomatized by melts and/or fluids either in the plagioclase‐peridotite or the spinel‐peridotite field. At least four stages of recrystallization have been identified in the garnet peridotites based on an analysis of reaction textures and mineral compositions. Stage I was most probably a spinel peridotite stage, as inferred from the presence of chromian spinel and aluminous pyroxenes. Stage II is a UHPM stage defined by the assemblage garnet + olivine + low‐Al orthopyroxene + clinopyroxene + Cr‐spinel. Garnet formed as exsolutions from clinopyroxene, coronas around Cr‐spinel, and porphyroblasts. Stage III is a decompression stage, manifested by the formation of kelyphitic rims of high‐Al orthopyroxene, aluminous spinel, diopside and pargasitic hornblende replacing garnet. Stage IV is represented by the formation of tremolitic amphibole, chlorite, serpentine and talc. Geothermobarometric calculations using (i) garnet‐olivine and garnet‐orthopyroxene Fe‐Mg exchange thermometers and (ii) the Al‐in‐orthopyroxene barometer indicate that the peak of metamorphism (stage II) occurred at conditions of around 900 °C and 4 GPa. These results suggest that garnet peridotites in the Pohorje Mountains experienced UHPM during the Cretaceous orogeny. We propose that UHPM resulted from deep subduction of continental crust, which incorporated mantle peridotites from the upper plate, in an intracontinental subduction zone. Sinking of the overlying mantle and lower crustal wedge into the asthenosphere (slab extraction) caused the main stage of unroofing of the UHP rocks during the Upper Cretaceous. Final exhumation was achieved by Miocene extensional core complex formation.     

大别-苏鲁造山带大理岩碳氧同位素地球化学研究

大别-苏鲁造山带的大理岩分布非常广泛,在三叠纪的陆-陆碰撞中,经受了不同程度的变质作用。本文对分布在大别地区北淮阳、苏家河、桐柏、宿松和苏鲁地区张八岭、五莲和坪上等地区的浅变质大理岩进行了碳氧同位素分析。结果发现,除了张八岭大理岩δ~(13)C值出现明显正异常(1‰～8‰)外,其他地区大理岩的δ~(13)C值均处于0±2‰(PDB)范围之内。所有地区大理岩的δ~(18)O值都有不同程度的降低,最低的δ~(18)O值达到4.5‰(SMOW)。与前人对大别-苏鲁超高压大理岩碳氧同位素研究结果相对比,我们发现大理岩δ~(13)C值分布与岩石是否经过超高压没有联系,而主要反映了其原岩沉积的时代和环境,并且其特征可以与发生在新元古代的冰川事件相关联。区域性的δ~(18)O值降低则说明,大部分岩石都经过了流体交换,并且流体的主要成分是水,含碳很少或者不舍碳,因此流体的来源是大气降水,可能与新元古代冰川溶融有关。     

Military training area in Kras (Slovenia)

 Slovenia's main military training area at Poček is located in the mountainous Javorniki Watershed. This is a karstic district without surface drainage or river valleys. The typical landscapes are conical hills and plateaus with many dolines. The lithology, tectonic structure and speleological data indicate a typical karst aquifer with underground water moving rapidly through fissures and conduits. Little attenuation occurs in such conditions and as a result there is a high risk of pollution. Tracer tests have shown that a significant proportion of the water recharging the Malni and Vipava springs comes from the vicinity of the military training area. As a result any polluting activities taking place within the military training area are likely to affect the two springs. This is a very serious matter as the springs have been developed to provide the water supply for the population of south-western Slovenia. Received: 20 April 1998 · Accepted: 24 August 1998     

Chromium in minerals as tracer of the polycyclic evolution of eclogite and related metabasite from the Pohorje Mountains,Slovenian Eastern Alps

Significantly different peak pressure–temperature (P–T) conditions (18–26 kbar and 630–760°C versus 29–37 kbar and 750–940°C) have previously been published for eclogite and related metabasites from the south-eastern flank of the Pohorje Mountains in Slovenia. These rocks can show a bimodal distribution of chromium in the rock-forming minerals, particularly garnet, the role of which in their metamorphic evolution is unclear. Therefore, we studied an eclogite and a related rock with clinopyroxene containing only 17 mol% jadeite + acmite (sample 18Ca35a). KαCr intensity maps of garnet particularly in sample 18Ca35a show a sharp irregular boundary between the core (Gt1) and the mantle (Gt2). Gt1 of millimetre-sized garnet in this rock is nearly Cr-free and unzoned, whereas Gt2 is of different composition (0.22 wt.% Cr₂O₃) and slightly zoned. Nearly Cr-free amphibole, (clino)zoisite, kyanite and staurolite inclusions are present in Gt1. The matrix consists of garnet and Cr-bearing clinopyroxene, (clino)zoisite and amphibole. Thermodynamic modelling suggests peak P–T conditions of 22.5 ± 2 kbar at 710 ± 25°C (Gt1) and 23 ± 2 kbar at 700 ± 25°C (Gt2) in both samples. We interpret these findings to suggest that olivine- and hornblende-bearing gabbros with some chromite experienced early metamorphism in the eclogite facies, when Gt1 formed. The rock was subsequently exhumed and cooled leading to significant garnet corrosion. A second stage of metamorphism, recognized by mappable Cr contents in garnet, led to the growth of Gt2 and other Cr-bearing minerals at the expense of chromite relics, which survived stage I. The peak P–T conditions of stage II are compatible with those previously derived by same authors and support the view that probably no ultrahigh-pressure eclogite exists in the Pohorje Mountains. We relate the two metamorphic events to the Cretaceous and Palaeogene high-pressure events recently reported from micaschists of the Pohorje Mountains.     

Macroseismic practice in Slovenia

In 1986, a project was started concerning the improvement of macroseismic data management in Slovenia. It was decided to establish a network of collaborators all over Slovenia (20 251 km², approx. 2 million inhabitants), dense enough to allow the use of the MSK scale. Since the uniform spatial distribution with desired density of collaborators is hard to achieve, several methods are being used to obtain new collaborators. At present we have approximately 4100 collaborators in our computer supported database.When an earthquake is felt in Slovenia, the seismologist decides to what areas the questionnaires are to be sent. The prospective observers can be chosen by two criteria: density and quality marks. The density mark allows us to choose a number of observers in the same town or village, based mostly on the quality of answers and demographic conditions. The quality mark is computed, combined with the previous marks, and updated every time a completed questionnaire is returned.The average number of shocks for which the questionnaires are being sent is about 25 per year during the normal seismic activity. The average number of questionnaires is approximately 300 per event. The percentage of the returned questionnaires is above 66%. A user-friendly, interactive program has been developed to manage the database with information about collaborators, to select an area, density and quality threshold of inquiry, and to print addresses onto questionnaires.     

Miocene emplacement and rapid cooling of the Pohorje pluton at the Alpine-Pannonian-Dinaridic junction,Slovenia

New laser ablation-inductive coupled plasma-mass spectrometry U-Pb analyses on oscillatory-zoned zircon imply Early Miocene crystallization (18.64 ± 0.11 Ma) of the Pohorje pluton at the southeastern margin of the Eastern Alps (northern Slovenia). Inherited zircon cores indicate two crustal sources: a late Variscan magmatic population (~270–290 Ma), and an early Neoproterozoic one (850–900 Ma) with juvenile Hf isotope composition close to that of depleted mantle. Initial εHf of Miocene zircon points to an additional, more juvenile source component of the Miocene magma, which could be either a juvenile Phanerozoic crust or the Miocene mantle. The new U-Pb isotope age of the Pohorje pluton seriously questions its attribution to the Oligocene age ‘Periadriatic’ intrusions. The new data imply a temporal coincidence with 19–15 Ma magmatism in the Pannonian Basin system, more specifically in the Styrian Basin. K-Ar mineral- and whole rock ages from the pluton itself and cogenetic shallow intrusive dacitic rocks (~18–16 Ma), as well as zircon fission track data (17.7–15.6 Ma), gave late Early to early Middle Miocene ages, indicating rapid cooling of the pluton within about 3 Million years. Medium-grade Austroalpine metamorphics north and south of the pluton were reheated and subsequently cooled together. Outcrop- and micro scale structures record deformation of the Pohorje pluton and few related mafic and dacitic dykes under greenschist facies conditions. Part of the solidstate fabrics indicate E–W oriented stretching and vertical thinning, while steeply dipping foliation and NW–SE trending lineation are also present. The E–W oriented lineation is parallel to the direction of subsequent brittle extension, which resulted in normal faulting and tilting of the earlier ductile fabric at around the Early / Middle Miocene boundary; normal faulting was combined with strike-slip faulting. Renewed N–S compression may be related to late Miocene to Quaternary dextral faulting in the area. The documented syn-cooling extensional structures and part of the strike-slip faults can be interpreted as being related to lateral extrusion of the Eastern Alps and/or to back-arc rifting in the Pannonian Basin.     

Flow and solute transport monitoring in the karst aquifer in SW Slovenia

The role of the unsaturated zone in the karst aquifer hydraulic behaviour was brought into focus in these studies of the catchment of the Hubelj spring (SW Slovenia). The variations of natural tracers in precipitation and in groundwater during a summer storm event made it possible to trace local flow and solute transport in the observed aquifer. The results produced data on the aquifer recharge, storage and discharge processes, as well as on mechanisms that affected them, which reflects a karst groundwater dynamics also at a regional scale. They point out the significance of effects of the fast preferential flow—epiflow that is the main factor controlling solute/contaminant transport towards the aquifer saturated zone. Numerous arguments indicate that the karst aquifer flow and solute transport mechanisms depend on the hydraulic behaviour of the epikarst zone.     

Tracking meteoric infiltration into a magmatic-hydrothermal system: A cathodoluminescence, oxygen isotope and trace element study of quartz from Mt. Leyshon, Australia

The oxygen isotope and trace element composition of hydrothermal quartz has been integrated with scanning electron microscope-cathodoluminescence (SEM-CL) images and fluid inclusion properties to track fluid sources and hydrothermal processes in the Mt. Leyshon Au deposit, Australia. Oxygen isotope and trace element data were collected on parallel traverses across the same quartz sections, using secondary isotope mass spectrometry (SIMS) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS), respectively, with SEM-CL images obtained before analysis for petrographic context. Over the 280 to 650 °C quartz precipitation range suggested by fluid inclusion microthermometry, δ¹⁸O_quartz varies from 0.0 to 14.4‰, corresponding to a wide range of equilibrium δ¹⁸O_fluid values, from-6.1 to 10.2‰ (vs. V-SMOW). The δ¹⁸O_quartz signature varies systematically among distinct SEM-CL quartz generations (both within and between samples), and can be correlated with variations in temperature and fluid composition, but is independent of intra-generational oscillatory zoning. In contrast, Al and Li concentrations correlate broadly with CL intensity in oscillatory quartz, whereas their concentration is unpredictable in sealed fractures and overgrowths. Concentrations of B, Mg, Na, P, Cl, K, Ti, Mn, Fe, Ge, and Sn are independent of Al, Li, and oscillatory CL features, but Ti correlates with quartz precipitation temperature. Although no systematic correlation between δ¹⁸O_quartz and trace element concentrations was found, complementary patterns exist in narrow overgrowths of low δ¹⁸O_quartz ( 0‰) and high Al (> 10,000 ppma). These quartz zones likely formed during the incursion of ¹⁸O-depleted meteoric water into the magmatically-dominated Mt. Leyshon hydrothermal system. We interpret the highest Al concentrations as the result of high quartz precipitation rates, triggered by depressurisation of the hydrothermal cell. The decoupling of oxygen isotope and trace element patterns in quartz leads to the suggestion that (1) under most circumstances, temperature and fluid chemistry dominate δ¹⁸O_quartz, and (2) the trace element record, and in particular Al and Li, is influenced by the superimposed effects of quartz precipitation rate.     

Quantitative high resolution cathodoluminescence spectroscopy of diagenetic and hydrothermal dolomites

A combination of high resolution cathodoluminescence-spectroscopy (HRS-CL=high resolution spectroscopy of cathodoluminescence emission) with spatial resolving trace element analyses (PIXE=proton induced X-ray emission) is used to establish a method for the quantitative determination of the Mn-content of diagenetic and hydrothermal dolomites using the measurements of peak areas of Mn-activated CL emission bands. This method takes into account the overlap of the CL broad bands of Mn²⁺ in the Mg- and the Ca-lattice-position of dolomite. There is a linear correlation between the peak areas and Mn concentration up to approx. 1000–1500 ppm. Thus, CL spectroscopy allows a determination of Mn concentrations below the abilities of PIXE (10–15 ppm) to less than 1 ppm by extrapolation of this linear relation.

Up to an Fe-content of approx. 2000 ppm, no quenching effect of Fe on this linear relationship occurs. However, Fe-contents above 2000 ppm result in a decrease of Mn-induced luminescence. Even at Fe-concentration >25,000 ppm spectroscopy reveals that Mn-activated CL of dolomite is not entirely extinguished.     

Laboratory and case studies of thermal cycling and stored strain on the stability of selected marbles

Studies of marble panels from the exterior of two buildings document the processes leading to bowing of the material. Bowing of panels is most extensive in those areas that are exposed to direct or reflected thermal energy. The thermal anisotropic behavior of calcite results in grain-boundary separation, grain sliding and microfracturing. The resulting loss of strength is one factor leading to bowing. The development of bows further reduces the panel strength as the outer portions elongate by inelastic deformation mechanisms. Laboratory experiments cycling marble samples for over 200 cycles at three temperatures up to 107°C above room conditions show similar strength losses as the natural situation. The second factor contributing to the bowing process is the release of residual elastic strain. The strain is in part stored in the marble from its geologic history, but may also be accumulated during thermal cycling due to the properties of calcite. Marble panels have been found to bow when stored outside, but not attached to any framework, indicating that the release of residual strain is a critical factor in producing the bows.     

Diagenetic effects on the well yield of dolomite aquifers in Slovenia

Diagenetic effects upon the hydraulic parameters of dolomite aquifers were examined. Results indicate that dolomites affected only by late (burial) diagenesis are economically more interesting to exploit than those formed first by early and then also affected by late diagenesis, as the values of most studied hydraulic parameters (transmissivity, specific capacity, linearized specific capacity and maximum yields) are higher in the former group. Data were collected from the hydrogeological reports of 298 wells in dolomites from Permian to Cretaceous age in Slovenia, classified in a relational hydrogeological database and analyzed by statistical methods. The studied parameters are hydraulic conductivity K, transmissivity T, specific capacity q (=Q/s), linearized specific capacity Ql (=q/d) and maximum yields Q _max. Values of the studied parameters are distributed log-normally according to most normality tests and span several orders of magnitude. Statistical tests show significant differences between the “late” and “early + late” groups for parameters q, Ql and T, and non-significant differences for K and Q _max.     

Factors influencing the hydraulic properties of wells in dolomite aquifers of Slovenia

The influence of eight factors on hydraulic parameters (transmissivity, hydraulic conductivity, specific capacity, specific capacity index and maximum yields) are analysed, with data based on hydrogeological reports of 298 wells in dolomite aquifers in Slovenia. Influence of lithological properties is very significant, with the highest values of analysed variables observed in pure late-diagenetic intensely fractured Cordevolian dolomites, followed by Anisian and Late Triassic (‘Main’ dolomite) dolomites with high carbonate content and high primary porosity. The hydraulic parameters are not dependent on aquifer age, partial penetration, and well depth. The effects of depth to the water table and existence of low permeability overburden are not of major importance. The hydraulic parameter values are higher the closer to a river the wells are located, and topographic setting has a major effect. From the well reports, it was not always deduced whether the values of hydraulic conductivity and transmissivity stand for the values of the fractures or of the matrix, so it is proposed that when there is doubt as to whether these values are properly calculated, the most accurate parameters that can be used for a further prediction of aquifer yield are the specific capacity and, to a somewhat lesser extent, the specific capacity index.

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Résumé  L’influence de 8 facteurs sur les paramètres hydrauliques (transmissivité, perméabilité, débit spécifique, courbe caractéristique et débit critique) est analysée sur des données issues des rapports de 298 puits dans les aquifères dolomitiques de Slovénie. L’influence des propriétés lithologiques est très significative : les valeurs les plus élevées sont observées dans les dolomies cordevoliennes pures, intensément fracturées et de diagénèse tardive, puis dans les dolomies de l’Anisien et du Trias Supérieur, avec une teneur élevée en carbonates et une forte porosité primaire. Les paramètres hydrauliques ne dépendent pas de l’age de l’aquifère, de la pénétration partielle ou de la profondeur. Les effets du niveau piézométrique et de l’existence d’une couverture peu perméable sont mineurs. Les paramètres hydrauliques augmentent à proximité des rivières, et la topographie a une influence majeure. Les rapports de forage ne stipulent pas systématiquement si les valeurs de perméabilité et de transmissivité sont relatives au réseau de fractures ou à la matrice ; il a par conséquent été proposé qu’en cas de doute sur le calcul de ces valeurs, les paramètres les plus significatifs pour remonter à la productivité de l’aquifère soient le débit spécifique et, dans une moindre mesure, la courbe caractéristique.

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Resumen  Se analiza la influencia de ocho factores sobre parámetros hidráulicos (transmisividad, conductividad hidráulica, capacidad específica, índice de capacidad específica, y rendimientos máximos) en base a datos de reportes hidrogeológicos de 298 pozos en acuíferos de dolomía en Eslovenia. La influencia de las propiedades litológicas es muy significativa con los valores más altos de variables analizadas presentes en dolomías Cordevolianas con diagénesis tardía fracturadas intensamente, seguidas por dolomías (dolomía “Principal”) del Anisiano y Triásico Tardío con alto contenido de carbonato y alta porosidad primaria. Los valores de los parámetros hidráulicos no son dependientes de la edad del acuífero, penetración parcial, y profundidad del pozo. Los efectos de profundidad al nivel freático y existencia de cobertura de baja permeabilidad no son de importancia fundamental. Los valores de los parámetros hidráulicos son más altos mientras más cerca de un río se localizan los pozos y el ámbito topográfico tiene un efecto principal. No se pudo deducir de los reportes de los pozos si los valores de transmisividad y conductividad hidráulica representan valores de las fracturas o de la matriz, de modo que se propone que cuando exista duda en cuanto a que si estos valores se han calculado de manera adecuada, los parámetros de mayor precisión que pueden utilizarse para una predicción futura del rendimiento del acuífero son la capacidad específica y, en menor medida, el índice de capacidad específica.

     

The vulnerability of karst springs—a case study of the Hubelj spring (SW Slovenia)

The hydraulic behaviour of the karst aquifer in the Hubelj spring catchment area (SW Slovenia) was studied by using an indirect research method based on natural tracers. The variations of natural tracers (in precipitation and in groundwater) during the storm event made possible the separation of the Hubelj spring storm hydrograph by the three-component separation technique. The results produced information on the aquifer recharge, storage and discharge processes, as well as on the mechanisms that affected them. They verified the so-called epikarst hypothesis presuming that an important part of a karst aquifer recharge reaches rapidly and intensively from the epikarst zone. It was demonstrated that epikarst water could occupy up to 50% of the spring discharge during precipitation events. This phenomenon could have important consequences on protection and management of the problems of karst aquifers, including engineering problems in karst areas. With this respect the results could give way to new engineering ideas.     

Weathering of marbles and granites in marine environment: petrophysical properties and special role of atmospheric salts

 The aim of this paper was to study the weathering mechanism of marbles and granites exposed to the marine environment at the Delos archaeological site. Alterations, as granular disintegration, contour scaling and alveolus formations, can be observed either at the base of blocks and columns, or at the median-high zones of monuments. A white marble, which originated from Naxos Island, had a weak porosity (0.2%). Its porous network was organized into two subnetworks of rectilinear and sinuous cracks, which limited capillary transfer to ∼10 cm. The granite, which originated from Delos Island, had a relatively high porosity (2.15%), and had a well-connected system of cracks and microporous zones of weathered minerals. This homogeneous network allowed good capillary transfer for long distances (1–2 m). For the marble, as for the granite, evaporation occurred mainly at depth in the stone, and encouraged its deterioration. This damage depends on the dissolution and crystallization of salts, which occur in cycles. First, by the capillary transfer of water and salt from the ground, when the stones are located near the sea. This processes can explain the deterioration of the marble and the granite bases, and the decay of granite on all its surfaces. Second, by fixation of water vapor by sea salt deposited on the stone by wind. This phenomenon can explain the degradations observed on the median-high parts of monuments in marble and granite, even though, for the granite, the first mechanism was more active.     

Groundwater and highways interaction: past and present experiences of highway construction in Slovenia

During the planning, designing, construction, operation and maintenance of highways, groundwater can be of important environmental and constructional constraint that can significantly influence the safety operation of traffic and of big influence on the operational costs of highways. To classify and conceptualize the relation between groundwater and highways, three important groups of problems can be determined: groundwater protection from highway influences, protection of highway from groundwater and economic use of groundwater for highway operation. In the present study, groundwater management strategies are represented during all life cycles of highways. Greater emphasis is given to groundwater protection and field hydrogeological investigations for proper groundwater management related to the highway. The approach adopted in Slovenia and the role of hydrogeology is given as an illustration.     

The Shatter Belt and the European Core - A Geopolitical Discussion on the Untypical Case of Slovenia

Europe in general is in a great state of change. States uniting with difficulty, states collapsing in pain, newly freed states struggling for new political, economic, and social identities - it is a region in a true transition. The paper is focussing primarily on the European Shatter Belt, formerly known as Eastern Europe. This is in fact a subset of new and old nation-states in the region of Central and Eastern Europe or, to use an older, but increasingly popular term, Mitteleuropa (Ruppert, 1997). Mitteleuropa is reemerging from the commotion resulting from the collapse of the old political order - communism. Our focus in this presentation is on personal experiences and observations. We will note the progress and positive dimensions of the change (transition) in the light of Europe's and NATO expansion. We will address the issues at two scales- at the international/national level and then, at the level of a Slovenian case study. This will enable us to discuss the natural system of the process of enlargement and incorporate supporting material of geographical, historical and social nature as envisioned by Hartshorne. Since the collapse of communism, the region has experienced some serious traumas that vary in intensity across the region. Probably the greatest pain has been experienced in the former Yugoslavia - an estimated 150,000 have perished and about 2.5 millions have been displaced within and outside the country. Chaos still exists despite the protectorate arrangement in Bosnia. The hot spot Kosovo has yet to be calmed down. In parts of the region economic pain has been considerable. Every state of Mitteleuropa experienced absolute economic decline from 1990–1995; high inflation rates, increased economic inequality, high levels of poverty, increase of crime and more. Economic and psychological stress effect demographic processes. Things have partly changed to the better in the most recent years. The adoption of capitalism and a democratic political system has been painful, disorienting, and is still in progress. The democratization process varies considerably across the region and in some states is in jeopardy. Reformed communist parties had staged a restoration in nearly all of the states - in some winning the control of the government, in others gaining strong and influential positions, or both. But, two major processes promise future democracy, rule of law, wealth and stability in general. This is the decision of the member states of the European Union and NATO to incorporate some/several states of the Shatter Belt into their own zone of protection and/or federation. Nation-states of the region tend to follow the EU Agenda 2000 rules with Slovenia one of the first!     

Refining the timing of eclogite metamorphism: a geochemical,petrological, Sm-Nd and U-Pb case study from the Pohorje Mountains,Slovenia (Eastern Alps)

High-pressure metamorphism in the Pohorje Mountains of Slovenia (Austroalpine unit, Eastern Alps) affected N-MORB type metabasic and metapelitic lithologies. Thermodynamic calculations and equilibrium phase diagrams of kyanite–phengite-bearing eclogites reveal PT conditions of >2.1 GPa at T<750°C, but within the stability field of quartz. Metapelitic eclogite country rocks contain the assemblage garnet + phengite + kyanite + quartz, for which calculated peak pressure conditions are in good agreement with results obtained from eclogite samples. The eclogites contain a single population of spherical zircon with a low Th/U ratio. Combined constraints on the age of metamorphism come from U/Pb zircon as well as garnet–whole rock and mineral–mineral Sm-Nd analyses from eclogites. A coherent cluster of single zircon analyses yields a ²⁰⁶Pb/²³⁸U age of 90.7±1.0 Ma that is in good agreement with results from Sm-Nd garnet–whole rock regression of 90.7±3.9 and 90.1±2.0 Ma (εNd: +8) for two eclogite samples. The agreement between U-Pb and Sm-Nd age data strongly suggests an age of approximately 90 Ma for the pressure peak of the eclogites in the Pohorje Mountains. The presence of garnet, omphacite and quartz inclusions in unfractured zircon indicates high-pressure rather than ultrahigh pressure conditions. The analysed metapelite sample yields a Sm-Nd garnet–whole rock scatterchron age of 97±15 Ma. These data probably support a single P-T loop for mafic and pelitic lithologies of the Pohorje area and a late Cretaceous high-pressure event that affected the entire easternmost Austroalpine basement including the Koralpe and Saualpe eclogite type locality in the course of the complex collision of the Apulian microplate and Europe.     

Extreme hydrological events in karst areas of Slovenia,the case of the Unica River basin

The study presents natural hazards in Slovenia's karst, focusing on flooding in karst poljes. A specific study was done on the flood dynamics of two typical and connected karst poljes (Cerknica and Planina) of the Classical Karst region. In the case of particularly extreme hydrological conditions in the autumn of 2008, detailed analyses of the recharge-discharge regime and the interrelationship of flooding on the two poljes were done. Daily precipitation, discharge, and water level values from several monitoring sites were analyzed and cross-correlated, and additional hydrological analyses were done using a digital elevation model in order to acquire water level increase and decrease intensity, flood water volumes, and the extent of flooding and to understand the conditions controlling karst flooding. The results reveal that the hydrological functioning of the studied karst poljes is influenced by the hydrogeological and temporary hydrological conditions in the catchment area. The response of the binary karst system (i.e., the influence of autogenic and allogenic recharge) is especially distinct. The study shows that during extremely intense recharge, the reactions of karst aquifer systems to precipitation are as rapid as the response of surface waters (the water level of Cerknica Lake increased with an intensity of 38-63 cm/day or 55 m3/s respectively) while retention capacities are negligible. In contrast to flash floods, floods in karst areas may last from several weeks to several months. For the observed period a three-dimensional simulation of the flooding was made. At the maximum recorded water level, the volume of water on the Cerknica polje was 51 million m³, and 26 million m³ on the Planina polje. The maximum extent of flooding on the Cerknica polje was 23 km² and on the Planina polje 9.5 km². On the basis of the study, information was provided regarding future hazard mitigation. However, the study demonstrated that a sufficiently dense monitoring network is necessary to predict the occurrence and duration of floods with greater certainty.     

Problems of agriculture in Slovenia with special reference to Cirkovce

The transition in the Slovenian countryside is examined through a case study of Cirkovce, a local centre for the central southern section of the Dravsko polje plain where natural and socio-geographical factors underpin a mixed rural-urban structure. Farming is intensive, but a high percentage of people are now employed outside agriculture; a situation which is reflected clearly in the appearance of the settlement. The process of rural depopulation, balanced by the growth of employment in industry and services, is reflected in a secondary knot of settlement around Cirkovce's railway station. Agriculture is still very significant but there needs to be some consolidation of landholding to create larger units suitable for market production and food processing. But the village must also improve its range of functions and provide a better environment for the non-agricultural population which will become increasing important for its future development. This revised version was published online in July 2006 with corrections to the Cover Date.