Evolution of ore-forming fluids in the Bukovik-Kadiica porphyry Cu deposit, Republic of Macedonia

The Bukovik-Kadiica mineralized system is hosted by Tertiary dacitic and andesitic volcanic rocks which have intruded the basement of Palaeozoic schists in the Serbo-Macedonian Massif of eastern Macedonia. The latest geological exploration has confirmed that this porphyry copper mineralizationis characterized by a dominance of chalcocite and covellite with associated chalcopyrite, emplectite, and bornite, with the highest grades in a zone of supergene enrichment. Silicification is the dominant alteration within the mineralized system, whilst zones of potassic, phyllic, argillic, propylitic, and advanced argillic alteration are also present. Silicification and sulphide mineralization are located in stockworks in altered dacite and andesite breccia. Dissolution of primary sulphides and chemical leaching are evident in the zones of oxidation, dominated by limonite breccia.The main copper mineralization has a vertical extent between 90 and 220 m. Fluid inclusion studies of mineralized quartz veins have identified three separate groups of fluids: saline inclusions which homogenize at 326-501 °C and have a salinity of 32-45 wt% NaCl equiv., vapour-dominated inclusions which homogenize at 438-497 °C and have a salinity of 6–16 wt% NaCl equiv., and more dilute, two-phase vapour–liquid inclusions that homogenize at 360-627 °C and have a salinity of 3-24 wt% NaCl equiv

Egg Quality Characteristics in Autochthonous Genotypes of Chickens Raised on Macedonian Rural Farms

Egg quality characteristics of three different autochthonous chicken phenotypes (phenotype having ashy-silvery-brown leghorn laced plumage color, phenotype having light brown spangled plumage color and phenotype having black or blue plumage color) were examined. These types of chickens are mainly raised as backyard rural area flocks in the villages of R. Macedonia. The data were collected through first systematic approaches in phenotypical identification and characterisation of these autochthonous genotypes realized recently. Three small flocks of old hens collected from different villages and placed in control pens were established. No data about number of eggs/hen/year is available for the established flocks. Further investigations are needed to record productive (number of egg produced) and reproductive data. The plan was that additional, yearly production records be collected from the flock produced as offspring from established flock of old hens collected from different villages and placed in control pens. Set of 90 eggs was collected (30 eggs from each plumage phenotype) and basic egg quality parameters measured. Egg size (weight) was 50.71g for brown laced plumage phenotype, 60.48g for blue plumage phenotype and 52.6 g for light brown spangled plumage phenotype. Egg shell strength was 3965, 3628 and 3924 g/cm2 for brown laced, blue and brown spangled plumage phenotype, respectively. Light brown spangled plumage phenotype had the highest value of yolk color (10.29) and Hough Units (76.63) compared to brown laced (10.08 and 75.27) and blue (9.09 and 71.65) plumage phenotype

Generalized Synchronization in Ginzburg-Landau Equations with Local Coupling

The establishment of generalized chaotic synchronization in Ginzburg-Landau equations unidirectionally coupled at discrete points of space (local coupling) has been studied. It is shown that generalized syn-chronization regimes are also established with this type of coupling, but the necessary intensity of coupling issignificantly higher than that in the case of a spatially homogeneous couplingComment: 4 pages, 2 figure

The Sb–As Lojane Deposit (Republic of North Macedonia): Types of Ores and Conditions of Their Occurrence and Geochemical Features

This article presents the results of comprehensive studies of Sb–As ores from the Lojane deposit, located in the northeastern part of the Republic of North Macedonia, near the border with Serbia. Five types of Sb–As ores are distinguished in the deposit: brecciated realgar orpiment ores; realgar breccias; brecciated antimonite ores; massive, almost monomineral realgar ores; and realgar–antimonite nested ores. The ores are characterized not only by the unusual paragenesis of minerals of nickel, arsenic, and antimony, but also by a very close fusion of antimonite, realgar, and collomorphic quartz. A wide range of elements in ores (As, Sb, Cr, Ti, Mn, Ni, Mo, Co, Ag, Tl, U, etc.) is likely due to the combination of mineralization from multiple distinct parageneses that occurred at different times. Thermometric studies of fluid inclusions in quartz indicate a temperature range of Thom varying from 180 to 220°C, with an average value of 201°C. Studies of the isotopic composition of sulfur in antimonite and realgar showed fairly narrow intervals of δ34S values from – 5.19 to –0.26‰ and from –4.80 to 1.92, respectively, indicating an endogenous sulfur source. Based on these findings, the Lojane deposit can be attributed to the epithermal class

Generalized Chaotic Synchronizationin Coupled Ginzburg-Landau Equations

Generalized synchronization is analyzed in unidirectionally coupled oscillatory systems exhibiting spatiotemporal chaotic behavior described by Ginzburg-Landau equations. Several types of coupling betweenthe systems are analyzed. The largest spatial Lyapunov exponent is proposed as a new characteristic of the state of a distributed system, and its calculation is described for a distributed oscillatory system. Partial generalized synchronization is introduced as a new type of chaotic synchronization in spatially nonuniform distributed systems. The physical mechanisms responsible for the onset of generalized chaotic synchronization in spatially distributed oscillatory systems are elucidated. It is shown that the onset of generalized chaotic synchronization is described by a modified Ginzburg-Landau equation with additional dissipation irrespective of the type of coupling. The effect of noise on the onset of a generalized synchronization regime in coupled distributed systems is analyzed.Comment: 12 page

Plavica Epithermal Au–Ag–Cu Deposit in Eastern Macedonia: Geology and 3D Model of Valuable Component Distribution in Ore

The Plavica Au–Ag–Cu deposit is related to the large Neogene volcanic center, which complicates the paleocaldera in the central Kratovo–Zletovo ore district of eastern Macedonia. Based on the geology, ore mineralogy, wall-rock alteration, and fluid inclusions, the Plavica deposit has been referred to the epithermal high-sulfidation type. The general 3D model of orebody at this deposit is based on its general geological structure and complex distribution of metal contents. The framework of the 3D model, which has been constructed in the ArcGIS System, comprises 195 exploration boreholes 47295.8 m in total length. The 3D model allows to a better understanding of distribution of mineralization and supplements the geological data on the deposit

Ore loses and dilution of the ore vein no. 4 in the Zletovo mine, Republic of Macedonia

Zletovo mines have a tradition of exploration and exploitation of vein lead-zinc ores for almost a century. Ore losses and dilutions have always been imperative in production since traditional old methods of mining and low-productivity mineralization are used. In conditions of classical and sub-level method excavations used, the calculated ore losses in ore vein No. 4 are 13.5%, while at the level of all excavations in the Zletovo mines dilution averages at 10%. Ore dilution is also an important technical parameter and several possible variants were calculated. When analyzing the dilution that occurs during the preparation of the sub-level corridor with parameters such: different drop angle (45-60o), constant thickness of 1.47 m as the average vein thickness in the calculated ore reserves, width of the sub-level corridor of 1.57 m or to the width of the ore vein No. 4 were added 10 cm (left and right to 5 cm) as much as is taken in the calculation of the planned dilution and height of 2.5 m as suggested for this mining method, it can be noticed that the planned dilution during this method of mining ranges from 26.3% to 42.3%. In conditions of use of this underground method of excavation, parameters are selected that allow for the indicated lowering of the dilution. Namely, the thickness of the ore wire would be 1.47 m, the mining width would be 1.57 m, only 10 cm (left and right up to 5cm) to the thickness of the ore vein will be added, the height difference between the consecutive levels would be 7.5 m, dip angle of 45 to 60°, and with the excavation the whole ore vein would be covered in height. On the basis of these parameters, models were prepared in which the ore vein would have a different dip angle, from which the values for the planned ore dilution ranged from 6.7 to 7.8%, which is significantly lower than the average dilution in the Zletovo Mine

The Role of Magmatic and Hydrothermal Fluids in the Formation of the Sasa Pb-Zn-Ag Skarn Deposit, Republic of Macedonia

The Sasa Pb-Zn-Ag deposit belongs to the group of distal base metal skarn deposits. The deposit is located within the Serbo-Macedonian massif, a metamorphosed crystalline terrain of Precambrian to Paleozoic age. The mineralization, hosted by Paleozoic marbles, shows a strong lithological control. It is spatially and temporally associated with the calc-alkaline to shoshonitic post-collisional magmatism that affected the Balkan Peninsula during the Oligocene–Miocene time period and resulted in the formation of numerous magmatic–hydrothermal ore deposits. The mineralization at the Sasa Pb-Zn-Ag deposit shows many distinctive features typical for base metal skarn deposits including: (1) a carbonate lithology as the main immediate host of the mineralization; (2) a close spatial relation between the mineralization and magmatic bodies of an intermediate composition; (3) a presence of the prograde anhydrous Ca-Fe-Mg-Mn-silicate and the retrograde hydrous Ca-Fe-Mg-Mn ± Al-silicate mineral assemblages; (4) a deposition of base metal sulfides, predominately galena and sphalerite, during the hydrothermal stage; and (5) a post-ore stage characterized by the deposition of a large quantity of carbonates. The relatively simple, pyroxene-dominated, prograde mineralization at the Sasa Pb-Zn-Ag skarn deposit represents a product of the infiltration-driven metasomatism which resulted from an interaction of magmatic fluids with the host marble. The prograde stage occurred under conditions of a low water activity, low oxygen, sulfur and CO2 fugacities and a high K+/H+ molar ratio. The minimum pressure–temperature (P–T) conditions were estimated at 30 MPa and 405 ◦C. Mineralizing fluids were moderately saline and low density Ca-Na-chloride bearing aqueous solutions. The transition from the prograde to the retrograde stage was triggered by cooling of the system below 400 ◦C and the resulting ductile-to-brittle transition. The brittle conditions promoted reactivation of old (pre-Tertiary) faults and allowed progressive infiltration of ground waters and therefore increased the water activity and oxygen fugacity. At the same time, the lithostatic to hydrostatic transition decreased the pressure and enabled a more efficient degassing of magmatic volatiles. The progressive contribution of magmatic CO2 has been recognized from the retrograde mineral paragenesis as well as from the isotopic composition of associated carbonates. The retrograde mineral assemblages represented by amphiboles, epidote, chlorites, magnetite, pyrrhotite, quartz and carbonates, reflect conditions of high water activity, high oxygen and CO2 fugacities, a gradual increase in the sulfur fugacity and a low K+/H+ molar ratio. Infiltration fluids carried MgCl2 and had a slightly higher salinity compared to the prograde fluids. The maximum formation conditions for the retrograde stage are set at 375 ◦C and 200 MPa. The deposition of ore minerals, predominantly galena and sphalerite, occurred during the hydrothermal phase under a diminishing influence of magmatic CO2. The mixing of ore-bearing, Mg-Na-chloride or Fe2+-chloride, aqueous solutions with cold and diluted ground waters is the most plausible reason for the destabilization of metal–chloride complexes. However, neutralization of relatively acidic ore-bearing fluids during the interaction with the host lithology could have significantly contributed to the deposition. The post-ore, carbonate-dominated mineralization was deposited from diluted Ca-Na-Cl-bearing fluids of a near-neutral pH composition. The corresponding depositional temperature is estimated at below 300 ◦C

La lithotritie par laser, un regard vers l'avenir? [Lithotripsy with a laser, a look toward the future?]

In the last few years the treatment of urinary calculi has been dramatically transformed by new endoscopic methods and extracorporeal shock wave lithotripsy. Laser lithotripsy is in keeping with this evolution. After a short description of the principle of laser lithotripsy, a prototype pulsed dye laser lithotriptor, developed by the Centre d'applications laser, Ecole polytechnique federale de Lausanne, is presented. This device is compared with other lasers proposed for the same application