Economic Geology
nader taghipour; Tahereh Rabani; Reza Zahiri
Abstract
Coal deposits in Gheshlagh region are embedded in the sediments of Shemshak formation with lithological units such as sandstone, conglomerate, siltstone, limestone and argillite. For investigation of mineralogy and structural characteristics of Gheshlagh coal seams sampled of eleven coal seams in four ...
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Coal deposits in Gheshlagh region are embedded in the sediments of Shemshak formation with lithological units such as sandstone, conglomerate, siltstone, limestone and argillite. For investigation of mineralogy and structural characteristics of Gheshlagh coal seams sampled of eleven coal seams in four active mines. Occurrence of minerals with distribution and nature of organic – mineral bonds in coals seams of this region is considered by using of petrographic and XRD and FT-IR analyses. Study of hand specimen and polished section are approved the presence of clay minerals, pyrite, chalcopyrite, siderite and quartz. Also The presence of minerals like kaolinite, quartz, siderite, dolomite, calcite, pyrite, montmorillonite and biotite was revealed by XRD. Mineral–organic bands such as: OH, CO2, CH3, Si-O, S-S, C-S, Al-OH, carbonate minerals, C=C, aromatic and aliphatic CH have been identified by the FT-IR in Gheshlagh coal seams. Raman spectroscopic confirms the presence of the graphitic band (G) (1581 cm−1- 1585 cm−1) and the defect band (D1) (1341 cm−1 – 1352 cm−1) in Gheshlagh coal seams. Graphitic bands contain high intensity and insignificant broadening.
S. Esmailnezhad; N. Taghipour; A. A. Hassannezhad
Abstract
The Nukeh iron deposit is situated at the north of Semnan and at south of Central Alborz structural zone. Volcano-pyroclastic rocks with Eocene age are the host of this deposit. Iron mineralization occurs as massive, disseminated, vein and breccia types in the Nukeh deposit and magnetite, hematite, pyrite, ...
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The Nukeh iron deposit is situated at the north of Semnan and at south of Central Alborz structural zone. Volcano-pyroclastic rocks with Eocene age are the host of this deposit. Iron mineralization occurs as massive, disseminated, vein and breccia types in the Nukeh deposit and magnetite, hematite, pyrite, chalcopyrite, garnet, epidote, quartz and calcite are the main minerals in this deposit. Fluid inclusions and stable isotopes (O, C, S) have been used to reveal the physico-chemical characteristics of hydrothermal fluids and genesis of the Nukeh Fe deposit. Seven types of fluid inclusions are identified in quartz, according to the phase numbers, which include, liquid inclusions (L), liquid-rich inclusions (L+V), vapor-rich inclusions (V+L), vapor inclusions (V), simple brine inclusions (L+V+S), halite-bearing liquid inclusions (L+S) and opaque-bearing liquid-rich inclusions (L+V+O). The ranges of homogenization temperature and salinity of liquid-rich fluid inclusions in quartz are 100-200˚C and 10-20 wt. % NaCl equivalent, respectively, whereas the ranges of homogenization temperature and salinity of vapor-rich fluid inclusions are 350-500˚C and 10-30 wt. % NaCl equivalent, respectively. Also homogenization temperature and salinities of liquid-rich fluid inclusions in calcite in garnet (type a) and magnetite (type b) zones is 75-125 ˚C but the salinity of fluid inclusions in calcite in garnet zone (15-25 wt. % NaCl) is more than salinity of these inclusions in magnetite zone (10-20 wt. % NaCl). δ13C and δ18O values of calcite (n=15) vary between -1.9 to +0.1 ‰ (VPDB) and -19.4 to -14.9‰ (SMOW), respectively. The average value of δ18OWater is of +17.85‰ (SMOW) in the Nukeh Fe deposit is different from the values for the primary magmatic fluid. Pyrite is the main sulfide mineral in the Nukeh Fe deposit and δ34S values of pyrite (n=9) is within the range of +3.9 to +5.4 ‰ CDT . The source of sulfur is considered to be magmatic on this basis. Fluid inclusions and stable isotopic (O, C, S) data suggest that the ore-forming fluids evolved by the various mixtures of magmatic brines and meteoric water and probably the genesis of the Nukeh Fe deposit is similar to skarn deposits.
N. Taghipour; A. Aftabi; M.R. Ramezani
Abstract
The Miduk porphyry copper deposit is located in 85 Km northwest of Sarcheshmeh porphyry copper deposit, Kerman province. The deposit is hosted by Eocene volcanic rocks of andesite-basalt composition. The porphyry-type mineralization is associated with two calc-alkaline intrusive phases (P1 and Miduk ...
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The Miduk porphyry copper deposit is located in 85 Km northwest of Sarcheshmeh porphyry copper deposit, Kerman province. The deposit is hosted by Eocene volcanic rocks of andesite-basalt composition. The porphyry-type mineralization is associated with two calc-alkaline intrusive phases (P1 and Miduk porphyry) of Miocene age. Five hypogene alteration zones are distinguished in the Miduk deposit, magnetite-rich potassic, potassic, potassic-phyllic, phyllic and propylitic. The main stage of mineralization consists of chalcopyrite, magnetite and anhydrite in potassic alteration zone. The mineralization is mostly associated with Miduk porphyry intrusive phase. Three different types of biotite including magmatic, magmatic affected by hydrothermal fluids and secondary are distinguished at the Miduk deposit. Magmatic type biotites affected by hydrothermal fluids and secondary biotites contain higher XMg values than the magmatic biotites. The XMg are positively correlated with Si, Al, Mg, K, Mg/Ti, but negatively correlated with Al×Ti, Fe, Na, Fe/Ti contents. The variations of Cu, Mo, Au and Ag are controlled by vein - type alteration and mineralization zones. The tonnage of deposit is about 170 Mt with average grade of 0.82 % Cu, 0.007% Mo, 82 ppb Au and 1.8 ppm Ag, respectively. Highest values of Mo and Au occur in leached and oxide, supergene sulfide mineralization, phyllic and potassic-phyllic alteration zones, respectively. Gold displays positive correlation with Cu in magnetite-rich potassic and potassic alteration zones. Based on petrography, mineralogy, alteration halos and patterns of Cu, Au, Ag and Mo, the Miduk porphyry copper deposit is similar to those of continental arc setting porphyry copper deposits.
