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The Olympias Pb-Zn(Au, Ag) sulfide ore deposit, E. Chalkidiki, N. Greece, is hosted by marbles of the polymetamorphic Kerdilia
Formation of Paleozoic or older age. The geologic environment of the ore also comprises biotite-hornblende gneisses and amphibolites
intruded by Tertiary pegmatite-aplite dikes, lamprophyre dikes, the 30-Ma Stratoni granodiorite, and porphyritic stocks. Only
limited parts of the deposit display shear folding and brecciation; most of it is undeformed. Microthermometry of fluid inclusions
in gangue syn-ore quartz indicates three types of primary and pseudosecondary inclusions: (1) H2O-rich, 1–18 wt.% NaCl equivalent, <3.6 mol% CO2; (2) H2O-CO2 inclusions, <4wt.% NaCl equivalent, with variable CO2 contents, coexisting in both undeformed and deformed ore; (3) aqueous, highsalinity (28–32 wt,% NaCl equivalent) inclusions
found only in undeformed ore. Type 2 inclusions are differentiated into two sub-types: (2a) relatively constant CO2 content in the narrow range of 8–15 mol% and homogenization to the liquid phase; (2b) variable CO2 content between 18 and 50 mol% and homogenization to the vapor phase. Type 1 and 2b inclusions are consistent with trapping
of two fluids by unmixing of a high-temperature, saline, aqueous, CO2-bearing fluid of possible magmatic origin, probably trapped in type 2a inclusions. Fluid unmixing and concomitant ore mineralization
took place at temperatures of 350 ± 30 °C and fluctuating pressures of less than 500 bar, for both undeformed and deformed
ores. The wide salinity range of type 1 inclusions probably represents a complex effect of salinity increase, due to fluid
unmixing and volatile loss, and dilution, due to mixing with low-salinity meteoric waters. High solute enrichment of the residual
liquid, due to extreme volatile loss during unmixing, may account for high salinity type 3 inclusions. The Olympias fluid
inclusion salinity-temperature gradients bear similarities to analogous gradients related to Pb-Zn ores formed in “granite”-hosted,
low-T distalskarn, skarn-free carbonate-replacement and epithermal environments. 相似文献
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Mineralium Deposita - On the basis of the Cu:Zn:Pb ratios, the Tsunokakezawa no. 1 orebody is classified as a ‘B’ (black) Kuroko ore sub-type. With the exception of zirconium the... 相似文献
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In hilly regions, retaining walls along roads, motorways and railway lines are numerous. In some cases the knowledge of the details of the construction is limited. If rehabilitation work becomes necessary, a detailed knowledge of the construction is desirable for the improved planning of maintenance and repair. This paper describes the application of Ground Penetrating Radar (GPR) for the inspection of retaining walls. The work was carried out in two steps. First, an investigation was carried out on large retaining walls at a Swiss motorway within the framework of a service contract. This included the development of an apparatus enabling high precision positioning of the antennas on the walls. Second, a pilot study was performed on a smaller wall with optimized acquisition and processing parameters. This included the use of antennas with different orientations and the fusion of the two corresponding datasets as well as true 3-D data processing. This paper describes the approaches to data acquisition and processing in the form of the two case studies. Results from different acquisition and processing strategies are compared and the benefits and limits are discussed. 相似文献
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Landsat (TM) imagery studies combined with photogeology, heliborne EM-radiometric interpretations and field data provided the fracture pattern in the eastern Chalkidiki peninsula, northern Greece. Processing of the respective data revealed the following four main directions of lineaments trending 070°–080°, 120°–130°, N-S and E-W. This fracture pattern is persistent in all geological units including the Tertiary basins and may represent reactivated older or even Tertiary fractures superimposed on all units. The control and the distribution of the major mineralization such as Pb---Zn (Au---Ag) massive sulphides, Mn (Fe) oxides, and porphyry Cu (Au) are of similar orientation to the deduced fracture pattern.These findings support the remote sensing is an important mineral exploration tool which can become quite effective when combined with ore deposit type, geochemical and geophysical data in partly explored areas. 相似文献
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Vein and stratabound base metal sulfide mineralization of the Thermes ore-field, Rhodope Massif, NE Greece, is hosted in marbles.
The Thermes area is a structurally complex, E-W-trending zone consisting of felsic gneisses alternating with amphibolites,
amphibole-biotite, and biotite gneisses, and marbles. These rocks have undergone amphibolite facies metamorphism (5–7 kbar,
580°–620°C), in Upper Cretaceous to Eocene times, and were subsequently retrograded to greenschist facies metamorphism of
Miocene age. Granitoids of Oligocene age, and volcanic rocks of Eocene-Oligocene age, crosscut the metamorphic rocks. Two
major base metal sulfide ore varieties occur in the Thermes ore-field. The first comprises brecciated vein Pb-Zn mineralization,
related to NNWand NNE-trending faults. The second comprises stratabound (manto) polymetallic, and Pb-Zn replacement ores with
associated veins. On the basis of ore geochemistry, as well as field and textural evidence, these two ore varieties form part
of a vein associated skarnreplacement base metal sulfide ore system. Based on fluid inclusion data in quartz, together with
the iron content of sphalerites and existing lead and sulfur isotope data, it is suggested that after the cessation of the
regional amphibolite facies metamorphism circulating evolved meteoric waters, probably with magmatic fluid contributions,
deposited sulfide ores at temperatures of 200°2-400°C, and pressures of less than 300 bar. Ore was deposited as a result of
increase in pH of the mineralizing fluids due to fluid-rock interaction, and adiabatic cooling and/or simple cooling accompanying
fluid boiling. Thermochemical considerations indicate a pH increase from about 4 to 7 and a decrease in
and
. 相似文献
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S. I. Kalogeropoulos 《Mineralium Deposita》1985,20(2):135-142
Tetsusekiei (literally, iron quartz) is in the form of thin, discontinuous beds that occur in the hanging wall of the Kuroko-type massive sulphide ores and at some distance beyond ore, along the uppermost part of the ore horizon tuff. The presence of tetsusekiei within a volcano-sedimentary sequence marks a horizon of fossil hydrothermal activity. Tetsusekiei shows elevated concentrations in trace elements of exhalative input relative to normal pelagic sediments and consists of two components; a clastic and a chemical component. Discriminant analysis applied to the following three groups: chemical component of tetsusekiei, clastic component of tetsusekiei and the upper part of the ore horizon tuff which is stratigraphically equivalent to tetsusekiei, has aided in providing the exploration geologist with a number of statistically significant major and trace elements that may be useful to exploration. The lateral distribution of the statistically significant major elements, expressed in the alteration index $$\operatorname{R} \% = \frac{{\left( {K_2 O + MgO} \right) \times 100}}{{K_2 O + Na_2 O + MgO + CaO}}$$ (Ishikawa et al. 1976) for the clastic component of tetsusekiei along the same stratigraphic horizon, shows an increase from about 50% to 90% approaching the Fukazawa mine from the northwest. The trace elements which are of exhalative origin show a relatively erratic distribution. In addition, the accommodation of barium, which is of exhalative origin, in the sericite constituent of the clastic component, combined with its higher concentration in the clastic relative to that in the chemical component, may indicate the presence of sulphide and/or barite ore lower in the stratigraphy. 相似文献
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