Authors:János Földessy, Éva Seress-Hartai, and Géza Szebényi
The Lahóca and Recsk Deep ore complex was formed in relation with andesite volcanics and diorite porphyry intrusives of Paleogene age. The zone is long known for significant enrichment of Cu, Pb and Zn ores. The presence of gold was recorded in the early years of the Lahóca mine. Epithermal and mesothermal gold enrichments are both known in the ore complex. In the epithermal zone low and high sulfidation varieties were identified on the volcanic level of the complex. In the mesothermal zone, significant gold enrichment was indicated in the porphyry copper and skarn copper, zinc ore zones and Pb-Zn veins. In the high sulfidation and the mesothermal copper skarn ore types a moderate correlation between Au and Cu was recorded.
Authors:Robab Hajialioghli, Mohssen Moazzen, and Ralf Milke
The Kaleybar nepheline syenite intrusion forms the largest silica undersaturated alkaline exposure in northwestern Iran. It consists of various rock types ranging from nepheline syenite to nepheline diorite that were emplaced during Eocene-Oligocene times, corresponding to the Alpine orogeny. The essential rock-forming minerals in nepheline syenite are plagioclase, K-feldspar, nepheline and amphibole. Clinopyroxene is the dominant phase in nepheline diorites. Titanian garnet occurs as an uncommon accessory phase forming reddish to deep brown individual grains.
Chemically it is intermediate between Ti-andradite (67 to 78 mole %) and grossular (21 to 33 mole %) with TiO2 contents ranging from 1.5 to 5.0 wt %. Stoichiometry and R-mode factor analysis on garnet chemistry show that the dominant exchange vectors are Si-Ti and Al-Fe substitutions in the tetrahedral and octahedral crystal sites, respectively. A magmatic origin of the investigated Ti-garnet is suggested on the basis of mineralogical criteria and chemical properties.
Transport and sorption of water-soluble 85Sr2+ and 125I− in the columns with beds of crushed crystalline rocks from synthetic groundwater has been studied under dynamic flow conditions.
Samples of crystalline rocks: diorite-I, diorite-II, gabbro, granite and tonalite, having the grain size between 0.25 and
0.80 mm, were used. Plastic syringes of 8.8 cm length and 2.1 cm in diameter were applied as columns. The synthetic groundwater
was pumped downward through the columns with a seepage velocity of about 0.2 cm/min and the given radioactive nuclide was
added into the water stream individually in a form of a short pulse. In case of 85Sr, desorption from diorite-I was also studied using an artificial acid rainfall and then, the longitudinal distribution of
the residual 85Sr activity along the bed was measured. Retardation, distribution and hydrodynamic dispersion coefficients were determined
by the evaluation of respective breakthrough curves. A corrected integral form of a simple advection–dispersion equation was
derived and used for fitting the experimental data. The Kd-parameters resulting from dynamic experiments were also compared with the results of static sorption experiments.
An accurate and simple method has been developed for the determination of Pt, Ru, Ir and other elements employing instrumental neutron activation analysis (INAA). Nondestructive analysis has been carried out for the determination of these elements in different rock samples such as Dolerite, Dyke Dolerite, Country Basalt, Hyaloclastite, Trachyte, Ijolite, Spillite, Diorite and Lamprophyre from various locations like Daman, Tapti, Murud, Talasari, Ranala and Bassein in Maharashtra state. High flux provided by the CIRUS reactor (1×1013 n cm–2s–1) has been used for thermal neutron bombardment followed by radioassaying of the (n,) products on a HPGe detector coupled to a PC-based MCA unit.
Authors:Andrea Varga, Béla Raucsik, Zsuzsanna Hartyáni, and György Szakmány
The clay mineralogical and chemical compositions of Upper Carboniferous siliciclastic rocks from the western flank of the Villány Mountains (Téseny Sandstone Formation) have been investigated to determine paleoweathering conditions, as well as to appraise the influence of the post-depositional processes upon source rock signature. The clay-mineral assemblage of the samples consists predominantly of illite±muscovite, suggesting a potassium metasomatism in the Téseny clastics. Therefore the use of the Chemical Index of Alteration (CIA), which provides a consistent quantitative framework for examining weathering, leads to erroneous conclusions without correction for K-metasomatism. When considered in Al2O3-CaO* + Na2O-K2O (A-CN-K) compositional space, orthogneiss and igneous rock clasts selected from the Téseny conglomerate reflect two different weathering trends; one (including orthogneiss, quartz diorite, and andesite samples) shows an ideal trend observed for granodioritic rocks, and the other (including aplite, rhyodacite, and rhyolite samples) follows a trend from a slightly more K-feldspar-rich fresh rock composition than that of average granite. Intermediate to intense chemical weathering of the source areas is indicated by premetasomatized CIA values of 77–84 for the samples from borehole Siklósbodony-1, suggesting that these rocks have gained about 6–7% K2O (in A-CN-K space) during metasomatism.
In the Pannonian Basin three Paleogene igneous regions can be outlined, namely the Zala Basin Shear Zone, the Velence Mts and the Recsk Region. These igneous regions are aligned along the easternmost Periadriatic-Balaton Lineament System. The igneous bodies are built up mostly by effusive rocks (andesite, dacite and basaltic andesite); however, intrusive rocks (tonalite, diorite) have been identified as well. The radiometric age of the effusive and intrusive rocks is scattered around 30 Ma, which falls into the range of the igneous bodies aligned along the Periadriatic Line (Bergell, Adamello, Riesenferner, Karawanke, etc.). Nevertheless, an Eocene onset of the magmatic activity in the Pannonian Basin is accepted on the basis of biostratigraphic data. As major and trace element composition range of the Paleogene igneous suites in the Pannonian Basin are basically the same, they are thought to have undergone the same pre-crystallization history. Geochemical characteristics of these calc-alkaline igneous rocks suggest that the magmatic activity represents a post-syncollisional volcanic arc environment.
Permo-Triassic rift-related magmatism in the Dinarides produced an intrusive gabbro-diorite-syenite-granite formation and an extrusive basalt-andesite-dacite formation with abundant pyroclastic rocks. They are spatially and genetically related to Late Permian to Norian rift-related sedimentary formations of the Adriatic-Dinaridic carbonate platform (ADCP). The volcanic and pyroclastic rocks are interlayered with fossiliferous sediments that range between the Late Permian and Middle Norian; the plutonic rocks, which are intrusive into Late Paleozoic and Scythian-Anisian sediments, have radiometric ages ranging between 262 and 212 Ma. Based on major and trace element contents, rocks of the Permo-Triassic magmatic association originated by fractional crystallization from primitive alkalic basalt to olivine tholeiite melts. Volcanic rocks were affected by strong ocean-hydrothermal metamorphism. Initial 87Sr/86Sr ratio of 0.703 and d18O of 5.6‰ of the most primitive rocks indicate an upper mantle origin. Most initial 87Sr/86Sr ratios range between 0.704-0.707, indicating a slight degree of crustal contamination. The Permo-Triassic igneous rocks of the Dinarides represent a specific and autonomous paleorift-related association, which cannot be correlated with the magmatic associations either from recent oceans or with alkali rocks from the Cenozoic African rift and Permian Oslo graben.
Authors:H. Widestrand, P. Andersson, J. Byegård, G. Skarnemark, M. Skålberg, and E. Wass
Three radially converging in situ migration experiments over a distance of 5 m were performed in a single fracture at a depth of 400 m in the Äspö Hard Rock Laboratory. Injection and breakthrough curves were obtained for uranine,H3HO (HTO), 22Na+, 42K+, 47Ca2+, 58Co(II), 82Br–, 85Sr2+, 86Rb+, 99mTc (no breakthrough), 131I–, 131,133Ba2+ and 134,137Cs+. The in situ experiments lasted for nearly 1.5 years, with single experimental times up to 10,000 hours. The tracer concentrations span over seven orders of magnitude between injection and sampling under practically undisturbed chemical conditions. Dynamic ranges in the breakthrough curves of up to four orders of magnitude were obtained. Thus, the use of radioactive (especially -emitting) tracers showed to be a most useful tool for in situ tracer experiments. The relative retardation sequence obtained in the field experiment was Na < Ca Sr < K < Ba Rb < Co Cs, which was the same as the relative sequence of the sorption coefficients obtained in the laboratory experiments using crushed rock material. Thus, no scale effect was indicated in the relative retardation sequence between laboratory and field experiments. High recoveries, >90%, were obtained for uranine, HTO, Br, I, Na and Sr and lower recoveries for Ba, Rb, Cs and Co. However, there were indications that there would have been higher recoveries of these elements if it had been possible to continue monitoring over longer experimental times. The low recoveries of Cs and Co indicate either slowly reversible or non-reversible sorption behavior. The laboratory diffusion experiments showed lower diffusivities and porosities and somewhat lower sorptivity of all studied tracers in the site-specific rock samples, dominated by mylonite, than in the diorite host rock. Matrix diffusion and associated sorption within the rock matrix is indicated in the in situ experiments, although this can not be verified without modeling that involves such processes.
Authors:Majid Sudi Ajirlu, Mohssen Moazzen, and Robab Hajialioghli
Late Jurassic ages (176–144 Ma) in the SSMB and granodiorite–diorite of Middle Jurassic age (166–167 Ma) in the UDMB.
In the ZOB, the Neyriz, Kermanshah, and Haji-Abad Ophiolites are unconformably covered by Late Cretaceous limestone and