Iranian Journal of Crystallography and Mineralogy
Year:2000 | Volume:8 | Issue:1|Papers Count:6

Qaleh-Zari mine is the largest Cu-Au vein type deposit in Iran and is located about 182 km south of Birjand (Khorasan province). The ore grade ranges from Cu= 0.5-8%, Au= 0.5-15 ppm, and Ag= 20-150 ppm. Mineralization concentrated in three major veins. Host rocks are mainly andesite to basaltic andesite (Paleocene-Eocene). The main paragenesis is: quartz, hematite (specularite), chlorite, chalcopyrite, ±pyrite, ±Ag-sulfosalts, and ± gold. Samples were collected from three veins at depth of -70, -100, -135, and -170 meters. At each level, samples are taken every 10m. Chlorites are mainly Fe-rich ripidolite, however a few sampels are brunsvigite and pycnochlorite. Temperature of chlorites formation were calculated based on the Cathelineau and Nieva (1985) equation. The chlorites were formed between 260-300°C. The temperature of chlorite formation is 10-30°C less than temperature measured from fluid inclusion. Using chlorite composition and t1uid inclusion data from Qaleh- Zari, new equation is presented for calculation of temperature for chlorite formation. The ore fluid contained. log mH2S= -3 to -3.5, log mH2< -5.5 , log fO2= -30 to -29.

In this research, Complex [Cd (phen)2(NO3)] was synthesized and the structure was determined by single-crystal X-ray diffraction method. This complex was synthesized by using 1, 10 - Phenanthroline and each of complexes [Cd (Meurea)6] (NO3) and [Cd (urea)4(NO3)] at 50-60°C. This complex crystallizes in tric1inic crystal system, space group P (-1) (2) with two molecules in the unit cell. Lattice parameters of this compound are: a= 9.6008(5)Å               b= 9.6044(3) Å              c= 13.4376(11) Åα= 99.5624(4)°              β= 99.5564(6)°              У= 105.0862(3)°V= 1152.65(13) Å          Dcalc= 1.7221 mg/m3After structural determination, Rand Rw constants decreased to 0.0772 and 0.0935, respectively. The Cd atom in this complex was eight-coordinated. In addition, Ir and XRD studies also carried out.

Based on this study, the average gold and silver grades in the Sar Cheshmeh porphyry copper deposit are 0.06 and 1.22 g/t respectively which are very different from the ones reported previously. In the biotitic andesite and altered phyllic/potassic samples from the stock, the high positive correlation between the hypogene copper and gold grades (r=0.81), and gold and silver grades (r=0.61), and gold and silver with the hypogene copper grade (r≥0.72), indicate: (1) the contemporaneous deposition of copper, gold and silver, and (2) gold is probably present in the form of exsolution, invisible solid solution and native or electrum within the chalcopyrite grains. Within the secondary sulfide enrichment zone, the gold grade is two times more than the hypogene grade. Silver also indicates the highest concentration within the leached/oxide and secondary sulfide enrichment zones.This study indicates that the Sar Cheshmeh deposit is a gold and silver poor porphyry copper - molybdenum deposit.

Abstract: Antimony mineralization occured in Hamedan district (Faghireh) which is related to Alvand Granitoids. The mineralization occured as a series of veins. Thickness of veins are variable and reach up to 0.7m. The veins are emplaced along high angle faults. These faults acted as a pathway for migration of ore fluids. Veins are composed of stibnite, pyrite, realgar and orpiment with quartz as a gangue. The textures of veins are open space filling, however brecciations also occured. Monzogranites, which formed the main part of Alvand pluton, is the host of quartz - stibnite veins. Monzogranites are composed of quartz, sodium plagioclase (oligoclase), orthoclase, biotite and sometimes muscovite.The veins are composed of 30.5% antimony, 0.83 ppm gold and 498 ppm arsenic. Based on geochemical studies, Sb, Au, AS, Ag, Hg, Sn, Ni, Co and Cr contents of host rocks are much higher than the world's average monzograniets and have probably anomalies. Spiderdiagrams show an identical pattern for host rocks and veins, which strongly suggests that these veins are cogenetic with the intrusive rocks (monzogranite).In summary, with all geological evidences in the region, it can be concluded that the mineralization is probably occured in the epithermal type.

Effloresce means formation of crystals or whitish deposits on the surfaces of objects. The appearance of these crystals are due to the type of art works, pigment, binding factor used, conservation treatments and the environment in which the objects are kept. In order to study the components of eft10rescence and the reasons for thier formation, samples were collected from the sediments present on the surfaces of twenty six ceramic objects. These objects were excavated from regions with different climaticconditions, and were all unglazed, and belonged to the first or second millennium BC. Fourier transform infrared spectroscopy (Fr-IR), X-ray diffraction (XRD) and wet chemical analysis were used for analysing of these minute samples. The results showed that the deposits consisted of either one or a mixture of gypsum, calcite, hydrated ferric chloride, feldspar, pyroxene, hematite and halite. Also the soil of region was analysed and the effects of the environmental factors on components and amount of eft10rescence was studied.

Optically sector - twinned garnet was found in a piemontite quartz schist in the Asemi-gawa area from the Sanbagawa metamorphic belt. The Sanbagawa metamorphic belt was formed during a regional Cretaceous intermediate high pressure type of metamorphism which is present through Southwest Japan. The garnet contains abundant inclusions of piemontite, quartz, hematite, braunite, talc and sodic amphibole. It is almost homogenous spessartine garnet (Xsps = 0.85). Piemontite occurs both in matrix and as inclusion in garnet and albite and it usually shows distinct zonation in which core of the grain contains lower Fe3+ and higher Mn3+ - and Al-contents than those of the rim. The garnet is anisotropic and composed of several parts or sectors visible in crossed polars. They show different patterns such as octahedral, hexahedral and tetrahedral in which optical orientation and extinction position are roughly symmetrical. A rhombododecahedral model garnet was used to interpret the geometry of the optically sector structure and show that sectors with symmetrical Miller's indices have similar optical properties. Textural relation and systematic partitioning of Mn3+ , Fe3+ and Al among garnet, piemontite and braunite indicate that garnet formation is due to the piemontite and braunite reaction.