Economic Geology
Fatemeh Sabahi; Mohammad Lotfi; Peyman Afzal; nima nezafati
Abstract
Gardaneshir carbonate-hosted Pb-Zn deposit on the ground of study area located southwest of Ardestan in Isfahan province. Base on lithostratigraphy,the main structure, besides the small outcrops of Jurassic shales, has been made up of carbonate and detrital rock materials depending on Paleozoic,Triassic ...
Read More
Gardaneshir carbonate-hosted Pb-Zn deposit on the ground of study area located southwest of Ardestan in Isfahan province. Base on lithostratigraphy,the main structure, besides the small outcrops of Jurassic shales, has been made up of carbonate and detrital rock materials depending on Paleozoic,Triassic and Cretaceous time stages. Dolomitic carbonate which is attributed to Shotori Formation , played the major role of host rock in ore-mineralization. Ore-mineral description obtained from the mineralized zone and caused the following ore-paragenesis in ascending order.of:pyrite,chalcopyrite,galena,sphalerite,malachite,cerussite,smithsonite,iron oxides and gangues of barite, quartz and calcite. Physico-chemical information of ore-solutions performed by entrapped fluid inclusion studies in gangue minerals. Liquid-rich two phase(L+V) inclusions as predominant types were recognized. These type of inclusions are homogenized into liquid state with a range of TH and related salinities between; TH :78 to 183 and 216 to 283°C, Salinity:3.5 to 9.7 and 10.2 to 25 wt% NaCl eq. The microthermometric data reflect the nature of two population of fluid inclusions originating from different sources. The source materials could have been provided by basinal brines, derived during compaction of sediments in a shallow sea environment and by movement into sediments, the stratabound Pb-Zn deposit are formed. Furthermore, the negative delta value ranges(δ34S) from -0.6 ‰ to -20.4 ‰ that have been extracted by galena can be an evidence of bacterial sulfate reduction in a subsidence sedimentary basin. In conclusion, based on field, mineralogical, fluid inclusion and sulfur isotope evidence, we propose that Gardaneshir Pb-Zn deposit is a stratabound carbonate hosted of Mississipi Valley Type(MVT).
Economic Geology
Mohammad Boomeri; Somayeh Naruyi; Mohammadreza Ghodsi
Abstract
The Chah Sorbi area is located in the Sistan suture zone. The geology in the Chah Sorbi, from old to young, are flysch type rocks, Zahedan granitoid, subvolcanic granodiorite porphyry, dioritic to granodioritic dikes and recent deposits. The Pb mineralization in the study area occurs as thin and short ...
Read More
The Chah Sorbi area is located in the Sistan suture zone. The geology in the Chah Sorbi, from old to young, are flysch type rocks, Zahedan granitoid, subvolcanic granodiorite porphyry, dioritic to granodioritic dikes and recent deposits. The Pb mineralization in the study area occurs as thin and short galena-bearing veins associated with pyrite, quartz, calcite, goethite and limonite. The host rocks are flysch and the subvolcanics that are undergone phyllic and argillic alteration. Propylitic alteration occurs in most dikes in the area and is characterized by chlorite, calcite and epidote. In northeast part of the area, the subvolcanic rocks were intruded by quartz stockworks and was strongly altered. The most intensive and extensive alteration with these rocks is phyllic alteration that is characterized by pyrite, quartz and sericite. Cu mineralization in the stock is characterized by presence of Cu-carbonate and –sulfides. Galena-bearing veins are probably epithermal type in the Chah Sorbi area that is situated in margin of a porphyry Cu system. Major and minor elements were measured in 7 least altered samples from intrusive rocks. The igneous rocks in the study area are metaluminous that are formed from a calc-alkaline magma in a continental margin volcanic arc setting.
Economic Geology
Fardin mousivand; Fayeq Hashemi; Mehdi Rezaei-Kahkhaei; Amir Pakizeh
Abstract
The Darreh Amrood Pb (Ag) deposit is located in south of Ghohrood, in the Urumieh-Dokhtar magmatic arc (UDMA). Host rockes to the deposit are Middle to Late Eocene grey-green siliceous tuff and crystal lithic tuff. Geometry of orebodies is stratabound, irregular, and semiconcordant to discordant to layering ...
Read More
The Darreh Amrood Pb (Ag) deposit is located in south of Ghohrood, in the Urumieh-Dokhtar magmatic arc (UDMA). Host rockes to the deposit are Middle to Late Eocene grey-green siliceous tuff and crystal lithic tuff. Geometry of orebodies is stratabound, irregular, and semiconcordant to discordant to layering of the host rocks. Ore structures and textures are dominated by semi-massive to brecciated, banded and vein-veinlets. Main primary minerals are galena, pyrite and chalcopyrite, and secondary minerals are dominated by covelline, goethite and hematite. Gangue minerals are epidote, chlorite, sericite, clay minerals, quartz, calcite and barite. Wall rock alterations are dominated by epidote-chlorite and sericitic. The rare earth element (REE) pattern of ores is not similar to that of volcanic rocks in the footwall and hangingwall that is concordant with sub-seafloor replacement process for ore formation. Also Ce showed negative anomaly that can be attributed to Ce in the seawater. Also based on structural, stratigraphic, petrographic, textures, mineralogical, alteration and geochemical studies, it is inferred that the Pb (Ag) mineralization in the Darreh Amrood area occurred as bimodal felsic- or Kuroko-type volcanogenic massive sulfide (VMS) mineralization, and formed as sub-seafloor replacement. It should be noted that the Darreh Amrood deposit is the first recognition of base metal-rich and poor barite VMS mineralization in the UDMA.
Economic Geology
SHAHRAM RAHMANI; Hasan Zamanian; reza Zarei Sahamieh
Abstract
Abstract: The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran ...
Read More
Abstract: The study area is located 45Km NE Zanjan in the Azerbaijan-Western Alborz zone. Quartz-monzonite and dacitic brecciated tuffs are the main host rocks to the Lubin-Zardeh deposit. These rocks are predominantly of K-high calc-alkaline shoshonitic I-type, metaluminous magnesian affinities of Cordilleran type. The intrusive rocks are enriched in LILE, LREE and depleted from HFSE, MREE and HREE and Y. A listric-shaped REE pattern and average La/Yb ratios of host rock indicates higher water content and fO2 in the magma and hornblende fractionation. Their relatively low to moderate ISr values (0.7047–0.7051), positive εNd (t = 36 Ma) values (0.39–2.1) and TDM ages of 0.69 to 1.06 Ga, with Pb isotopic ratios of (206Pb/204Pb) i = 18.49–18.68, (207Pb/204Pb) i = 15.58–15.61 and (208Pb/204Pb) i = 38.33–38.77. Based on textural evidence (coarse amphibole crystals), geochemical data (major, trace and Rare earth elements) and isotopic contents of Pb, Sr-Nd, it is suggested that these rocks correspond to geochemical and isotopic compositions of the host rocks of porphyry and epithermal deposits in the Urmia Dokhtar zone of West Alborz-Azerbaijan (Arasbaran) and Eastern Pontides epithermal deposits, Turkey.
Z Boroumand; S Ghassa; M Moradian; H Abdollahi; Gh Fathabadi; K Fakhremoghadam
Abstract
In this research, the bioleaching process of mixture of sulfide and carbonate zinc and lead ore of Angouran Mine, whit local mixed mesophilic bacteria was studied. The purpose of this study was to indicate the effects of pulp density, Fe(II) concentration and initial pH in the zinc and lead bioleaching. ...
Read More
In this research, the bioleaching process of mixture of sulfide and carbonate zinc and lead ore of Angouran Mine, whit local mixed mesophilic bacteria was studied. The purpose of this study was to indicate the effects of pulp density, Fe(II) concentration and initial pH in the zinc and lead bioleaching. In Addition, the pH and Reduction-Oxidation Potential (ORP) have been monitored and evaluated during bioleaching process. The results showed that the zinc recovery through the bioleaching process (64.4 %) was much more than the leaching without bacteria (33.56 %). The results also showed, an increase in the pulp density caused a decrease in zinc recovery, and an increase in initial pH and ferrous concentration increased the zinc recovery. On the other hand, maximum lead recovery was 1.03 %. The study of bioleaching residual showed that the lead was recrystallized as Pb5(AsO4)3Cl. However, presenting the relation between mentioned parameters and Pb recovery was impossible due to lead precipitation. The results of this research could be used for bioleaching of high-grade Pb-Zn ores.
