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Fractured aquifers, especially dolomites, are important hydrocarbon reservoirs and sources of thermal and groundwater in many parts of the world, especially in the Alpine-Dinaric-Carpathian region. The most dominant porosity type is fracture porosity, which acts as the preferential fluid pathway in the subsurface, thus strongly controlling fluid flow. Outcrops provide valuable information for the characterization of fracture networks. Dolomite rock properties and structural and diagenetic processes result in fractured systems that can be considered fractals. The fracture network was analyzed on 14 vertical outcrops in 35 digitized photographs. The values of the fractal dimensions varied slightly by the software and method used, but the trends were consistent, which confirms that all methods are valid. Small values of fractal dimension indicate the dominance of a few small or large fractures, and high values of fractal dimension result from a combination of large numbers of small fractures accompanied by a few large fractures. The mean value of the fractal dimension for analyzed fracture networks was 1.648. The results indicate that the fracture network of the Upper Triassic dolomites can be approximated by fractal distribution and can be considered a natural fractal, and values can be extrapolated to higher and lower scales (1D and 3D).

The effect of Satureja montana L. extract (SM) and phenolic fraction of Satureja montana L. (PF) on the corrosion behaviour of iron in 0.1 mol L-1 sodium chloride solution was studied by electrochemical techniques, UV/Vis spectrophotometry and atomic absorption spectrometry. The results of all techniques showed that SM and PF contributed to iron corrosion inhibition. The calculated inhibition efficiency values were about 45% for SM and 55% for PF. Results indicate that the inhibitive action occurs via a precipitation of the Fe-complex onto the iron surface which resulting in a decrease of the passive current density. The atomic absorption spectrometry (AAS) method was applied to the quantitative determination of iron in solution. The obtained results demonstrated good agreement with results obtained by electrochemical techniques.

In the bauxite-bearing area of Jajce (Bosnia & Herzegovina), exploitation of karst bauxite has occurred for more than 40 years, during which time extensive geological and mining research was also conducted. Here, the geological map of the Jajce bauxite bearing-area (Bosnia & Herzegovina) at a scale of 1:25.000 is presented, accompanied by a geological column and regional geological cross-sections. The map shows the main stratigraphic and tectonic features and positions of the bauxite deposits of the area. This research area covers 343 km2, divided into two structural units with four bauxite districts, Liskovica, Bešpelj, Crvene Stijene and Poljane. The Liskovica-Bešpelj structural unit is tectonically very complex, characterized by W-E trending structures in subvertical, vertical and overturned positions. The Crvene Stijene-Poljane structural unit is characterized by gentle folds and normal faults. The geological map summarizes all the available data and represents the necessary basis for further geological and mining research of the area.

The paper presents a new approach to exploring bauxite deposits from underground mining works in the bauxites area of Bešpelj near Jajce in Bosnia and Herzegovina. In the area considered, bauxite deposits are being investigated and exploited over 60 years. Despite the high degree of exploration in the geologically intricate structures of Bešpelj there are numerous up to the unexplored reservoirs. Up to now, they have been mainly investigated by drilling from the surface into the wells net to dictate the legal regulations. Due to the increase in depths on which deposits are located and complex structural relationships, such research has become more and less effective. From the geological point of view, the bauxite deposits are in the horizontal position. But long-lasting geological evolution from the upper Cretaceous to the present, has led to deposits in very different structural positions. That is why we find them in a tilted position, in subvertical and vertical, and often in an inverse position. For further research to become rational and efficient, a new approach to exploring basement from underground mining works will be developed that will serve for exploration and then for the exploitation of bauxite deposits.

This paper presents results of fractal analysis of fracture systems in upper Triassic dolomites in Žumberak Mountain, Croatia. Mechanical rock characteristics together with structural and diagenetic processes results with fracture systems that can be considered as fractals. They are scale-invariant in specific range of scales. Distribution of fractures can be than described with power law distribution and fractal dimension. Fractal dimension is a measure of how fractures fill the space. Fractal dimension can be estimated form photographs of outcrops by converting photographs to binary photographs. In binary photo there is only black (rock or fractures) and white (fractures or rock). Fractal dimension is then estimated based on box-counting method. In this paper we present results of fractal analysis from three outcrops. Results are very similar to previous published results from outcrops of dolomites in Slovenia. Obtained fractal dimensions are in range 2,69-2,78 and it depends on how fracture systems are distributed in the outcrop. Lower values indicate smaller number of fractures and higher significance of larger fractures. Higher values indicate distribution of more similar sized fractures throughout whole outcrop. Fractal dimension is very significant parameter in rock fracture system characterisation sense it describes how fractures are distributed in the outcrop. It can be used in discrete fracture network modelling if spatial distribution of fractures is represented with power law distribution.

The successful exploration of dimension stone mainly depends on the quality, size, and shape of extractable blocks of dimension stone. The investigated area is in the Pelješac Peninsula (Croatia), in the External Dinarides orogeny, built from thick carbonate succession, characterized by relatively small deposits of high-quality dimension stone. These conditions demand challenging geological investigations in the “pre-quarry” phase to find optimal quarry location. The size and shape of dimension stone blocks are mainly controlled by fracture pattern systems. In the rugged, covered terrains, it is very hard to obtain a satisfactory amount of fracture data from the surface, so it is necessary to collect them from the underground. Borehole camera technology can visualize the inner part of the rock mass and measure the fracture characteristics. The main conclusions are as follows: (1) the digital borehole camera technology provides a quick, effective, and low-cost geological survey of fractured rock mass; (2) statistical fracture distribution parameters, P10, fracture spacing, Volumetric Joint Count (Jv) based on borehole wall survey can reflect the integrity of rock mass, providing a solid decision-making base for further investment plans and dimension stone excavation method.

In this paper we present and elaborate one example when bauxite was the main target of investigation. During reprocessing and reinterpreting original input data from locality “Crvene stijene” near Jajce in Bosnia and Herzegovina, it was established that bauxite hanging wall and footwall rocks in fact present even more valuable mineral resources, dimension stone. This paper presents results of reprocessing and reinterpretation of original data with focus not only on primary resource, but on resources that are developed in footwall and hanging wall. Final goal of the research was to optimize the ratio between research and exploration cost and total profit by exploration of all available mineral resources in the area. For that purpose, new method of bauxite (primary resource) and associated deposits is developed and named “integrated approach”. Integrated, joint evaluation of bauxite and associated deposits (dimension stone), would give far greater significance to whole area. Finally, with this new method, the ratio between overall profit and cost will be maximized.

Fractured aquifers, especially dolomites, are important hydrocarbon reservoirs and sources of thermal and groundwater in many parts of the world, especially in the Alpine-Dinaric-Carpathian region. The most dominant porosity type is fracture porosity, which acts as the preferential fluid pathway in the subsurface, thus strongly controlling fluid flow. Outcrops provide valuable information for the characterization of fracture networks. Dolomite rock properties and structural and diagenetic processes result in fractured systems that can be considered fractals. The fracture network was analyzed on 14 vertical outcrops in 35 digitized photographs. The values of the fractal dimensions varied slightly by the software and method used, but the trends were consistent, which confirms that all methods are valid. Small values of fractal dimension indicate the dominance of a few small or large fractures, and high values of fractal dimension result from a combination of large numbers of small fractures accompanied by a few large fractures. The mean value of the fractal dimension for analyzed fracture networks was 1.648. The results indicate that the fracture network of the Upper Triassic dolomites can be approximated by fractal distribution and can be considered a natural fractal, and values can be extrapolated to higher and lower scales (1D and 3D). [ABSTRACT FROM AUTHOR]

The paper presents the stratigraphy of Paleogene strata fromthe central part of carbonate Dinarides. The carbonate and the clasticrock units were stu died. Their contact with underlying Senonian limes toneis marked by unconformity as a result of Laramian tectonic phase.The unconformity is denoted by the abundance of bauxite deposits.The abundance of calcareous nanoplancton species as well asben tic foraminifera points at the sedimentation of Paleogene strataduring the Eocene period. The succession of sediments with easilyrecognizeable transgressive, inundation and regres sive features hasbeen established.Lithostratigraphical characteristics enabled the distinguishing oflarger lithofacies groups. The simultaneousness of carbonate rockswith lower part of clastic succession as well as the transitionallitho·facies have been approved. The simultaneous overburden of bauxitedeposits regardless of its lithology (carbonate of clastic) speaks infavour of the unite bauxitebearing phase.

Displacements of the Adriatic microplate, particularly of itssouthern part, are of crucial importance for the understanding ofrecent tectonic movements. Deformations of the structural fabric andthe resulting tectonic activity also encompass the studied area. Thereare four most active fault zones - Mosor-Biokovo, Zagvozd-Vrgorac-Metkoviæ, Trilj-Tihaljina-Èapljina and Imotski-Meðugorje-Popovopolje. In the explored area, these zones delimit the Imotsko polje.The calculated regional stress is oriented in the range between10-190¡ and 350-170¡. The relationship between the orientation ofstructural units and stress enables reverse displacements, most frequently in the direction of the south and south-east. The change instress orientation in the Mt. Biokovo hinterland makes the aforementioned fault zones surrounding the Imotsko polje favourably oriented in respect to the stress, thus enabling dextral horizontal tectonic transport of the structures in different fault blocks.In the two fault zones - Trilj-Tihaljina-Èapljina and Imotski-Meðugorje-Popovo polje, there are 98 outcrops suitable for the structuralgeology measurements. The obtained data on the local stress orientation and spatial displacement of structures are the most important.The character of faults and the most active fault sections are marked,as well as the local structures that are formed due to strong horizontalcomponent of structural displacement in the studied fault zones.Recent tectonic activity is confirmed by the occurrence of earthquakes.Spatial distribution of the earthquake epicentres depicts zonesof seismotectonic activity that are related to the aforementioned mostimportant fault zones. Two of the fault zones - Trilj-Tihaljina-Èapljinaand Imotski-Meðugorje-Popovo polje are especially well markedby earthquakes occurring at depths of between 3 and 15 km.

exploration area and for building of a detailed hydrogeological model, especially with complex geological models and 3-D structure shapes. Electrical sounding is based on a theoretical assumption of a horizontally stratified earth model, and electrical profiling maps only lateral resistivity changes at the same depth. Two-dimensional (2-D) electrical imaging (or 2-D electrical tomography), that has been introduced recently, can map the both vertical and lateral resistivity changes and provides for building three-dimensional (3-D) resistivity model of the underground. Exploration has been carried out in the area of the Seona spring to investigate the possibility for pumping more water during dry season, from the well located near the spring. The water of the Seona spring emerges from Badenian carbonate aquifer, which shows irregular 3-D shape and heterogeneous lithologic composition. A network consisting of four electrical profiles has been established to acquire a 3-D resistivity model, which can be transformed in a 3-D hydrogeological model. Inverse resistivity model sections revealed high resistivity zone which has been correlated with Badenian limestone by means of existing outcrops. Low resistivity zones point to the marly layers. Exploratory borehole located on the basis of electrical data has confirmed derived hydrogeological model from the electrical imaging data. Heterogeneous limestone aquifer has been uncovered at depth 8.2 – 55 m. The aquifer is weathered and karstificated with two main cavern intervals. Hydraulic connections between the caverns and the spring have been established during drilling, but also in a pump test by means of the airlift method. The presented case demonstrates great possibilities of the electrical imaging method in mapping of irregularly shaped aquifers and building of a precise 3-D hydrogeological model.

At the end of Pliensbachian or during the Toarcian, several carbonateplatforms were individualised by extensional tectonics in southernTethys, of which the Adriatic Carbonate Platform is one. As a uniqueand isolated shallow marine depositional system it existed until theend of the Cretaceous. In the Late Lias, the platform margins andslopes were formed by the individualisation processes. Due to thepresence of younger sedimentary cover and tectonic disruption fromthe Early Jurassic until the present, only small parts of the north-easternmargin and its slope are exposed at the surface.During the entire “life-span” of the platform, its NE margin andslope retained more or less the same palaeogeographic position – fromwestern to south-eastern Slovenia, through the central part of Croatia,western and central Bosnia, northern Herzegovina and Montenegroall the way to northern Albania. The region between Žumberak inCroatia and central Bosnia was the most dynamic part of the platformmargin during the Jurassic and Cretaceous. Shifts of the marginal andslope facies were recorded in Žumberak, where the platform area wasprogressively reduced during the period from the Lias to the Malm.At the same time, the platform was extended in central Bosnia andMontenegro. A more pronounced reduction of the platform in Cenomanian times marked the beginning of the process of disintegration.The end of the Cretaceous was also the end of the “life” of the AdriaticCarbonate Platform. It mostly became emergent, and the renewedshallow marine carbonate depositional environments in the Eocenewere short-lived and lacked the previous platform characteristics, aswell as the regional distribution and integrity.

Seismotectonically active zones are formed due to displacements of segments of the Adriatic micro-plate that differ in size and in their rate of movement, and by the resistance of the rock masses of the Dinarides. The spatial position of these zones can be determined through the locations of earthquake foci. The zones of seismotectonic activity are then correlated with the most important faults on the surface.The seismotectonically active zones are relatively steeply inclined in the shallowest 10-20 km, which is caused by the oblique contacts between the Adriatic micro-plate and the Dinarides. The zones are curved at depth in many cases, which reflects the compression of the area. Curved parts of the zones are characterised by the greatest pressures and also by the most frequent earthquakes. Mildly inclined zones reflect the reverse displacements in the area, also probably the activity on contacts between rock masses of different density, or the extension of the Adriatic micro-plate subduction. The southern part of the plate is the most active. The greatest pressures caused by these movements occur in the area between Mljet island and Dubrovnik. Therefore the majority of earthquakes, and notably the strongest ones, occur in the area between Split, Imotski, Hvar island and Dubrovnik, as well as along the Montenegro coast in a SE direction.

The extensively distributed bioclastic sedimentary bodies in the Podvrsko-Snjegavic Area, Mt. Psunj (Pozega Subdepression, Eastern Croatia) are mostly composed of fragments of bryozoans, echinoids, lamellibranchs and corallinaceans. Apart from this, a relatively compositionally uniform, but granulometrically variable bioclastic detritus occurs, which also contains a smaller proportion (5-30%) of siliciclastic grains of medium to coarse sand, as well as sporadic pebbles up to 60 mm in diameter. These sediments are characterised by remarkably large-scale cross-bedding with erosional surfaces clearly delimiting the sets. They are interpreted as shallow-marine shoreface subaqueous dunes, sand bars and barriers formed on the nearshore - mainly shoreface area during the Late Badenian in a high-energy depositional cycle with strong synsedimentary tectonics. With regard to the petroleum-geological reservoir characteristics, the described Middle Miocene cross-bedded biocalcarenites are compared with numerous large oil and gas pools globally, and in other localities in Croatia on the margins of inselberg massifs between the Drava and Sava rivers and south of the Sava river.

Gravelly Alluvial aquifer of Usora river is developed suitable for water-supply management Of the Usora region. It is a shallow uncon-fined aquifer of high conductivity. Its thickness reaches up to 4.5 meters, unconformably overlying Pliocene clays. The cover above this gravel-dominated layer is thin, partly permeable or completely missing. The aquifer is in fairly good hydraulic continuity with Usora river flow. Capacity of planned wells will lie directly dependent on the well-site positioning to optimal hydrogcoiogical conditions, well-construction modifications to critical flow values for the minimal water level periods, and particularly, on well screen-type selection and construction. Results obtained so far confirm the potential well capacity within range of 5 to 10 l/s (the paper is published in Croatian).

Investigation results of morphological and geological potential bauxite deposit indicators in the Mesihovina-Rakitno bauxitebearing sedimentary basin in Western Herzegovina are presented. Region with carbonate and clastic hangingwalls as well as those without overlying sediments have been studied. It was established that the expression and number of the indicators depend size as well as on character and thickness of hangingwall sediments. The morphological indicators are expressed as a particular relief forms situated right above the deposits or nearby and are a consequence of geological relations and exodynamic processes. Ihe numerous geological indicators resulted from complex geological events. The most important are: preore structural relations, the formation of paleorelief, peculiar way of hangingwall rocks sedimentation, lithification processes and the formation of the recent structural pattern. It has been observed that particular indicators should be recognized within a relatively thick succession of the overlying sediments which is of the great importance in the exploration of bauxite deposits.

The exploration of bauxite deposits in the region of the carbonaceous Dinarides has been performed by using different geological and geophysical methods. Deposits laying shallower or deeper below the roof sediments have so far most often been discovered by expensive drilling methods in a corresponding grid. Complex geological explorations have led to a series of valuable data thus enabling the application of other much more economical methods as well. In the region of the bauxite sedimentary basin Mesihovina-Rakitno, western Herzegovina, at the site of Studena vrila - after extensive geological explorations - a conclusion was drawn that the shallow seismic reflection geophysical method as well might be successfully applied in locating new bauxite deposits. In the paper, the geological framework of the bauxite deposits occurrences, stipulating the selection of this methode, will be presented. Measurements were performed on a known deposit (L-84, Povaljenica), completely defined by exploration drilling. The obtained results justify the selection of the shallow seismic reflection method as one of the methods for exploring bauxite deposits beneath the roof beds.

Featured Application: The presented methodology is a relatively fast and low-cost method that gives solid input into the state of the investigated rock mass, bedding orientation, degree of jointing, and preliminary block size estimation. All these parameters are very important for decision-making in the initial phase of quarry investment since these factors control the potential of the location for dimension stone deposit and type of excavation. The methodology is also applicable to hydrogeological (fractured aquifers), geotechnical, civil engineering, and engineering geology research (rockfalls, construction of roads, viaducts, railways, bridges, tunnels, etc.) where knowledge about fracture systems in the rock mass is crucial for further works. The successful exploration of dimension stone mainly depends on the quality, size, and shape of extractable blocks of dimension stone. The investigated area is in the Pelješac Peninsula (Croatia), in the External Dinarides orogeny, built from thick carbonate succession, characterized by relatively small deposits of high-quality dimension stone. These conditions demand challenging geological investigations in the "pre-quarry" phase to find optimal quarry location. The size and shape of dimension stone blocks are mainly controlled by fracture pattern systems. In the rugged, covered terrains, it is very hard to obtain a satisfactory amount of fracture data from the surface, so it is necessary to collect them from the underground. Borehole camera technology can visualize the inner part of the rock mass and measure the fracture characteristics. The main conclusions are as follows: (1) the digital borehole camera technology provides a quick, effective, and low-cost geological survey of fractured rock mass; (2) statistical fracture distribution parameters, P10, fracture spacing, Volumetric Joint Count (Jv) based on borehole wall survey can reflect the integrity of rock mass, providing a solid decision-making base for further investment plans and dimension stone excavation method. [ABSTRACT FROM AUTHOR]

In the bauxite-bearing area of Jajce (Bosnia & Herzegovina), exploitation of karst bauxite has occurred for more than 40 years, during which time extensive geological and mining research was also conducted. Here, the geological map of the Jajce bauxite bearing-area (Bosnia & Herzegovina) at a scale of 1:25.000 is presented, accompanied by a geological column and regional geological cross-sections. The map shows the main stratigraphic and tectonic features and positions of the bauxite deposits of the area. This research area covers 343 km2, divided into two structural units with four bauxite districts, Liskovica, Bešpelj, Crvene Stijene and Poljane. The Liskovica-Bešpelj structural unit is tectonically very complex, characterized by W-E trending structures in subvertical, vertical and overturned positions. The Crvene Stijene-Poljane structural unit is characterized by gentle folds and normal faults. The geological map summarizes all the available data and represents the necessary basis for further geological and mining research of the area. [ABSTRACT FROM AUTHOR]

This paper presents a new approach to exploring bauxite deposits from underground mining works in the bauxitebearing mines of Bešpelj near Jajce in Bosnia and Herzegovina. In the area under consideration, bauxite deposits have been investigated and exploited for over 60 years. Despite the high degree of exploration in the geologically complicated structures of Bešpelj, there are numerous unexplored reserves. Up to now, they have been mainly investigated by drilling from the surface into the borehole network as dictated by legal geological regulations. Due to the increase in depths on which deposits are located and complex structural relationships, such research has become more expensive and less effective. From a geological point of view, the bauxite deposits have developed in the horizontal position. However, longlasting geological evolution from the Upper Cretaceous to the present, has brought deposits in very different structural positions. That is why we find them in an inclined position, in subvertical and vertical, and often in an overturned position. For further research to become rational and efficient, a new approach of study from underground mining works was developed that will serve for study and then for the exploitation of bauxite deposits. [ABSTRACT FROM AUTHOR]

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Model studies of prebiotic chemistry have revealed compelling routes for the formation of the building blocks of proteins and RNA, but not DNA. Today, deoxynucleotides required for the construction of DNA are produced by reduction of nucleotides catalysed by ribonucleotide reductases, which are radical enzymes. This study considers potential non-enzymatic routes via intermediate radicals for the ancient formation of deoxynucleotides. In this context, several mechanisms for ribonucleotide reduction, in a putative H2S/HS. environment, are characterized using computational chemistry. A bio-inspired mechanistic cycle involving a keto intermediate and HSSH production is found to be potentially viable. An alternative pathway, proceeding through an enol intermediate is found to exhibit similar energetic requirements. Non-cyclical pathways, in which HSS. is generated in the final step instead of HS., show a markedly increased thermodynamic driving force (ca. 70 kJ mol−1) and thus warrant serious consideration in the context of the prebiotic ribonucleotide reduction. [ABSTRACT FROM AUTHOR]

New organic superbases have been designed using the concept of multiple intramolecular hydrogen bonds. Substituents capable of forming strong intramolecular H-bonds were selected on the basis of the energy of stabilization that occurs upon the formation of a complex between N,N',N"-trimethylguanidine and small model molecules. The proton affinities and the corresponding pKa values in acetonitrile of the new superbases are examined by Density Functional Theory (DFT). It is shown that N,N',N"-substitution of guanidine with appropriate substituents results in new organic superbases with gas phase proton affinities between 286 and 293 kcal mol-1, thus being 15 to 20 kcal mol-1 more basic than parental superbase N,N',N"-tris[(3-dimethylamino)propyl]-guanidine (tris-DMPG), whereas estimated pKa values in acetonitrile range between 29.5 and 33.2. [ABSTRACT FROM AUTHOR]

Karst aquifers are important sources of thermal and groundwater in many parts of the world, such as the Alpine–Dinaric–Carpathian region in Europe. The Upper Triassic dolomites are regionally recognized thermal and groundwater aquifers but also hydrocarbon reservoirs. They are characterized by predominantly fractured porosity, but the actual share of depositional and diagenetic porosity is rarely investigated. In this research, we presented the geometric characterization of the measured microporosity of the Upper Triassic dolomites of the Žumberak Mts (Croatia), through thin-section image processing and particle analysis techniques. Pore parameters were analyzed on microphotographs of impregnated thin sections in scale. A total of 2267 pores were isolated and analyzed. The following parameters were analyzed: pore area, pore perimeter, circularity, aspect ratio (AR), roundness, solidity, Feret AR, compactness, and fractal dimension. Furthermore, porosity was calculated based on the pore portion in each image. The effective porosity on rock samples was determined using saturation and buoyancy techniques as an accompanying research method. We analyzed distributions of each parameter, their correlation, and most of the parameters are characterized by an asymmetric or asymmetric normal distribution. Parameters that quantify pore irregularities have similar distributions, and their values indicate the high complexity of the pore geometry, which can significantly impact permeability. [ABSTRACT FROM AUTHOR]

In this paper we present and elaborate one research example when bauxite was the main target of the investigation. During reprocessing and reinterpretation of the original data from the "Crvene stijene" locality near Jajce in Bosnia and Herzegovina, it was established that bauxite hanging wall and footwall rocks in fact represent an even more valuable mineral resource, as "dimension stone". The final goal of the research was to optimize the ratio between research and exploration costs and total profit by exploration of all available mineral resources in the area. For that purpose, a new research evaluation method encompassing both bauxite (primary resource) and associated deposits was developed and named the "integrated approach". Integrated, joint evaluation of bauxite and associated deposits (dimension stone), gives a far greater economic significance to whole area. Finally, with this new method, the ratio between overall profit and cost will be optimized which results in significant increase in profit because all available deposits are considered for exploitation. Also this method can be applied on abandoned mining sites if there is some secondary profitable mineral deposit in the mine area. [ABSTRACT FROM AUTHOR]