Strata-bound barite deposits occur in Devonian dolomites, situated in the Mid-Bosnian Palaeozoic Schist Mountains. These contain barite as the main ore mineral (5.9 wt% SrSO4 on average and d34S= ...+8.3‰) which comprises 90-99 wt% of the bulk ores. The subordinate components are calcite, fluorite, Hg-Sb-tetrahedrite, pyrite and quartz.
Analysis of REE by INAA revealed an extremely low content of lanthanides (1.584 ppm), negative Eu anomalies (Eu3+/Eu+ = 0.7398), and (Tb)N/(La)N = 6.2 indicating late-stage mineralization.
Primary fluid inclusions show a uniform number of infilling phases (L+V+S), and persistent volume ratio. This indicates homogeneity of the hydrothermal ore-forming fluids and an absence of boiling phenomena at the time of fluorite formation. Th is between 200° and 310°C, with a distinctive maximum at 250°C. Tfm -20.3°C predominates but careful examinations of the early melting behaviour of the inclusions warrants the existence of Tfm -51°C, and the presence of CaCl2. High salinity between 25 and 26 wt% eq. NaCl was determined from the hydrohalite melting temperature (Tmh). Some additional daughter minerals are also present. Fluorite, barite and calcite formed from the high saline waters probably originated by mixing of heated hydrothermal fluids with the highly evolved post-Variscan Upper Permian formation waters. This is supported by the study of the isotopic composition of the carbon, oxygen and sulphur of the paragenetic carbonates and sulphides.
Syngenesis versus epigenesis in the Kupferschiefer genetic model is still a matter of controversy. The title of the article seems to be a paraphrase of a well-known paper by WEDEPOHL (1971), ..."Kupferschiefer as a prototype of syngenetic sedimentary ore deposits". It is intended, however, more as a paradigm for the genesis of the hydrogen-sulphide geochemical barrier, an important ore formation episode prior to heavy metal accumulation, which shows the utility of RENFRO's (1974) epigenetic model.
Barite mineralization in Lokve is a stratabound ore deposit conformably situated at the Permian-Triassic boundary. It bears only two ore minerals, barite and pyrite exclusively, separated into two distinct, juxtaposed horizons stretching for tens of kilometers.
The discovery of cryptalgal fabrics and other conspicious sedimentary features in underlying siliciclastics with massive pyrite and surmounting barite-bearing dolomites supports their affiliation to a tidal flat facies and sabkha environment. Barite and pyrite accumulation were formed by an early diagenetic, bacteriogenic sulphate reduction in a peritidal muddy environment, concommitant to a widespread process of evaporative dolomitization. The early diagenetic model is supported by an analysis of the sedimentary facies, trace element geochemistry and sulfur isotope distribution along two vertical profiles across the stratabound barite and pyrite mineralization.
The evaluation of the heavy metal discharge from liming materials into the arable soil in NW Croatia is based upon the contents of Fe, Mn, Pb, Cu, Zn, Cd, Co and Hg in the studied carbonate raw ...materials, obtained under simulated conditions of the lowest presumed acidity (pH>3) which can occur in the agroecological environment. From the agroecological viewpoint, the heavy metal contents of the analyzed liming materials are much lower than the permissible levels. Only cadmium contents indicate that a certain amount of care should be taken into account. Because cadmium is bound in labile forms (pH>3 soluble fraction), it has to be considered quite mobile and biologically available in limed arable soils that are affected by drastic pH changes in the agroecological environment.
Mineral and ore occurences at Mt. Ivanščica are situated in the Middle Triassic carbonate rocks and are of epigenetic origin. These occurences are characterised by simple paragenesis of primary ...sulphides of leads and zinc and traces of sulphides of iron and copper. This mineralization is similar to Mississippi Valley Pb-Zn deposits (the paper is published in Croatian).
The purpose of this study was a geochemical assessment of soils developed on a historical Pb–Ag mining site (galena with approx. 500 mg/kg of Ag) situated near the chapel of Sv. Jakob on the crest of ...Mt. Medvednica near Zagreb. A total of 100 brown forest (0–25 cm) soil samples were collected from the regular grid covering an area of approximately 75,000 m
2. Ten samples were selected for detailed chemical and mineralogical analyses. Pb, Zn, Cu, Hg values were obtained by analysis of aqua regia extracts, while residence sites of metals in soils were identified by sequential extraction analysis. Shallow soils developed above the historic mining site `Sv. Jakob' contain very high concentrations of Pb, Zn and Cd due to oxidation of primary sulphides in the near-surface weathering environment. The aqua regia extractable Pb values varied from 9 to 18,188 mg/kg, Zn from 12 to 9125 mg/kg, Cd from <0.25 to 189 mg/kg and total Hg from 0.06 to 1829 mg/kg. Distribution patterns of Pb, Zn, Cd and Hg outline both the surface extent of mineralization and the area affected by historical mining activities (tailings, exploration pits and trenches) which are today almost indistinguishable from the natural landscape. Pb and Cd are dominantly enriched in carbonate and Fe–Mn oxide fractions while Zn exhibits enrichment in organic-sulphide and Fe–Mn fractions. This distribution is probably the result of solubility controls for Cd and Pb in carbonates, affinity of Zn for organic material and coprecipitation of these elements with iron oxides. Fe, Cu and Ni are enriched in the organic-sulphide fraction, indicating that a part of pyrite has probably not been altered completely (or was recently incorporated in soil as a result of downslope movement and colluviation), and in the residual fraction. For the sequential extraction procedure used in this study, mobility and biological availability are assumed to decrease in the order of the metal extraction sequence. On this basis, the apparent mobility and potential bioavailability of the metals for contaminated soils are: Cd > Pb > Zn > Cu > Ni. Spatial distributions and high contents of Pb, Hg, and Zn in topsoils of the northern lowland residential parts of Zagreb were formerly attributed only to fossil fuel consumption and the flooding of the river Sava. The high contents of these elements in topsoils covering areas of historical mining sites situated within the Mt. Medvednica Protected Park of Nature are probably also sources of observed pollution. The streams that drain these areas are characterised by violent mudflows that flood northwestern parts of the city at least once every three years and deposit high quantities of mud. Studies that aim to determine this link are currently in their initial phases but evidently materials with high bioavailable contents of potentially toxic elements are being regularly supplied to the gardens and orchards of northwestern parts of Zagreb.
Ispiranje zlata iz recentnih i starih nanosa rijeka i potoka, jedan je od najstarijih oblika rudarenja, koji seže u predmetalno doba razvoja civilizacije (bakar i željezo). Razlog treba tražiti u ...neposrednoj upotrebi zlata bez znanja složene tehnologije pridobivanja čistog metala. Separacija teških minerala u vodotocima odvija se jednostavnim prirodnim procesom odnošenjem lakših mineralnih frakcija vodenom strujom. Postupci ispiranja zlata, korišteni od čovjeka, nisu ništa drugo nego kopiranje prirodnog procesa, uz male domišljate varijacije priručnog alata. U radu je opisana kratka povijest zlatarstva na Dravi, te data temeljita analiza geološke geneze zlatnih nanosa i mineraloški sastav dravskog zlata.
The Darnó Unit within the Zagorje-Mid-Transdanubian Megaunit is an allochtonous part of Dinarides in NE-Hungary and represents a relict of the Neotethyan accretionary complex. It contains blocks of ...submarine basalts of Triassic age in turbiditic sediments olistrostrome) of Jurassic age. The lava clogged in the lime mud at the original site of volcanism and developed closely packed pillow, pillow fragment hyaloclastite breccia, and peperite facies. Interaction
between the lava and the sea water produced mostly chloritic alteration of basalt and precipitation of hydrothermal calcite in amygdales, feeding channels of lava lobes and hyaloclastite breccia cements. Calcite is associated with chlorite, epidote, hematite and pyrite. Fluid inclusions in calcite infi llings record conditions of fluid/rock interaction. Salinities of fl uid inclusions (3.2–5.6 wt.% NaCl equiv. wt.%.) are close to the salinity of recent sea water and their homogenization temperatures are in the range of 80–150°C. Fluid inclusion data support interpretation that volcanic facies represent rapidly cooled distal zones away from the submarine volcanic centre. This is also confi rmed by the comparison to the volcanic and hydrothermal alteration facies of the submarine basalt lava-flow complex and associated pillow lava formation of Triassic age in the Hruškovec quarry in the Kalnik Mts., NW-Croatia. The obtained data contribute to understanding of the early history of Neotethyan evolution, i.e. dilemma about rifting or oceanization in Triassic time and offer new aspects of correlation between units of Dinaridic origin which had been displaced from their original setting by large scale Tertiary tectonic processes.
Samoborska Gora Mts. is situated within westernmost part of the Zagorje-Mid-Transdanubian zone of the Inner Dinarides. The Samoborska Gora Mts. consists dominantly of Permian unmetamorphosed ...siliciclastic sediments and evaporites, overlain by Lower Triassic sediments. Rude mineralization is hosted by Permian siliciclastic sediments, beneath gypsum and anhydrite strata. Central part of the deposit consists of 1.5 km long stratabound mineralization, grading laterally into ferruginous sandstone and protruding vertically into a gypsum-anhydrite layer. Siderite-polysulfide-barite-quartz veins are located underneath the stratabound mineralization. Late stage galena-barite veins overprints the formerly formed mineralization types.
The Rude ore deposit was generated by NaCl±CaCl2-H2O solutions. Stratabound mineralization was precipitated from solutions with salinities between 7 and 11 wt. % NaCl equ., homogenizing between 150°C to 230°C. Vein type mineralization derived from solutions with salinities between 4 and 20 wt. % NaCl equ., homogenizing between 80°C and 160°C, while late stage galena-barite veins were precipitated from solutions with salinities between 11 and 16 wt. % NaCl equ., homogenizing between 100°C to 140°C. Fluid inclusions bulk leachate chemistry recorded Na+>Mg2+>K+>Ca2+>Li+ and Cl - >SO42- ions. Sulfur isotope composition of barites and overlying gypsum steams from the Permian seawater sulfate, supported by increased Br- content, which follows successively the seawater evaporation line. The sulfur isotopic composition of sulfides varies between -0.2 and +12.5 ‰, as a result of thermal reduction of Permian marine sulfate. Ore-forming fluids were produced by hydrothermal convective cells (reflux brine model) and derived primarily from Permian seawater,- modified by evaporation and interaction with the Permian sedimentary rocks. Rude deposits in Samoborska Gora Mts. may be declared as a prototype of the Permian siderite-polysulfide-barite deposits, products of the rifting along the passive Gondwana margin, in the Inner Dinarides, and their equivalents in extension northeastward into Zagorje-Transdanubian Zone and Gemerides, and southeastward to Hellenide-Albanides. <-->
Samoborska Gora Mts. is situated within the westernmost part of the Zagorje–Mid–Transdanubian zone of the Inner Dinarides. The Samoborska Gora Mts. predominantly consists of Permian unmetamorphosed siliciclastic sediments and evaporites, overlain by Lower Triassic sediments. Rude mineralization is hosted by Permian siliciclastic sediments, below gypsum and anhydrite strata. The central part of the deposit consists of a 1.5 km long stratabound mineralization, grading laterally into ferruginous sandstone and protruding vertically into a gypsum–anhydrite layer. Siderite–polysulphide–barite–quartz veins are located below the stratabound mineralization. The stratiform part of the deposit is situated above the stratabound and consists of haematite lajer with barite concretions and veinlets. Late stage galena–barite veins overprint earlier types of mineralization.
The Rude ore deposit was generated by predominantly NaCl ±} CaCl2–H2O solutions. Detrital quartz from stratiform mineralization was precipitated from solutions with salinities between 7 and 11 wt. % NaCl equ., homogenizing between 150 °C to 230 °C. Stratabound/siderite–polysulphide–barite–quartz vein type mineralization was derived from solutions with salinities between 5 and 19 wt. % NaCl equ., homogenizing between 80 °C and 160 °C, while late stage galena–barite veins were precipitated from solutions with salinities between 11 and 16 wt. % NaCl equ., homogenizing between 100 °C to 140 °C. Fluid inclusion bulk leachate chemistry recorded Na+>Mg2+>K+>Ca2+>Li+ and Cl–>SO4 2–ions. Sulphur isotope composition of barites and overlying gypsum stems from Permian seawater sulphate, supported by increased Br– content, which follows successively the seawater evaporation line. The sulphur isotopic composition of sulphides varies between –0.2 and +12.5 ‰, as a result of thermal reduction of Permian marine sulphate. Ore–forming fluids were produced by hydrothermal convective cells (reflux brine model), and were derived primarily from Permian seawater, modified by evaporation and interaction with Permian sedimentary rocks. Rude deposits in Samoborska
Gora Mts. may be declared as a precursor? of the Permian siderite–polysulphide–barite deposits (products of rifting along the passive Gondwana margin), in the Inner Dinarides, and their equivalents extending northeastward into the Zagorje–Transdanubian Zone and the Gemerides, and southeastward to the Hellenide–Albanides.
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