Showing 13 results for Geochemical
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Volume 3, Issue 2 (10-1995)
Abstract
Homoginization temperature of fluorite [luid
indus ian indicate that mineralization has mostly take place
within the temperature ranging 70 to 1500C . the last ice
melting tcmpenttur ranges from 0 1O·2.2°C and shows that
salinity varies from 0 to 3.69 wt% equivalent NaC!.
Chemical analysis performed on The liquid phases of fluid
indusion show that mineralizing fluids were rich in Ca and
K. The above results along wilh data obtained by SEM
equipped with EDAX spectrophotometery reveals that
metal deposit of this mine were probably transported by
chloride complexes. Temperature decrease and boiling
accurancy were probably the cause of decomposition of
chloride complex at the depusitiunal sites.
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Volume 5, Issue 2 (10-1997)
Abstract
Geochemical variations of the Pro terozoic
dolomite samples close to the ore deposits in the Renison
mine area, Tasmania, Austra lia. arc the result of alteration.
The oxygen tsotope va lues of the most altered dolomites
surrounding the orc deposit indicates that these arc affected
oy hot (up to abou t 350°C) hydro thermal nuids. There is a
trend of decreasing lighter oxygen and carbon isotope values
LOwards the are deposit. Carbon isotope val ucs in dolomites
are significantly lighter than those least· altered dolomites
away from mineralised area, due to alteration ranging from
47 to 95% . Oxygen isotope values arc also significantly
li ghter close 10 the a re deposil, than less allered sa mples
away from mineral ised area. Alteration in oxygen rang ing
from 20 10 97% . Geochemical analys is also indicates th aI
Fe a nd Mn are very high but Ca, Mg, Sr and Na arc very
low in dolomile sa mples close 10 Ihe ore deposils. Thus, the
result of thi s study shows Ih at the gradual decreases in
oxygen and carbon isotope values, which corresponds to the
increasing a lt e ralion perce nt , lowards Ihe o rebody, a long
with e lemenlal composi tio ns, are us eful for recognition of
ore deposiLs.
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Volume 16, Issue 2 (7-2008)
Abstract
The study area is situated within the Lut Block 50 Km northeast of Ferdows. The oldest exposed rocks are Cretaceous limestone. Kerman conglomerate cover the limestone. Dacite-rhyodacite lava and pyroclastic rocks erupted over Kerman conglomerate. Volcanic activities took place at different time in Tertiary. The composition ranges between trachyandesite, andesite, andesite-basalt and rhyolitic tuff. Sub-volcanic diorite, monzodiorite, monzonite, quartz monzonite and granite porphyry intruded the volcanic rocks during Oligo-Miocene time. Both volcanic and intrusive rocks are K-rich calc-alkaline to shoshonitic. Intrusive rocks (except granite porphyry) are I-type granite and belong to magnetite series. The pattern of spider diagrams both volcanic and intrusive rocks are similar. In comparison with mantle, They are enriched in Cs, K, Rb, La and Zr and depleted in Ba, P and Ti. Two groups of alteration zones are recognized: 1- silicified assemblages (silica-sericite-propylitic, silica-propylitic & silica- sericite). This group is related to granitic magma. 2- propylitic-sericitic-argillic group which are associated with monzonite, quartz monzonite-diorite intrusive rocks. Mineralization associated with granite porphyry show Mo, Ag, Pb and Zn anomalies. Mineralization associated with monzonite, quartz monzonite-diorite show signs of porphyry copper. They have Cu, Au, Pb and Zn geochemical anomalies.
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Volume 21, Issue 1 (4-2013)
Abstract
Tarikdarreh prospect area is situated in northeastern Iran at the boundary between Central Iran and Kopet-Dagh structural zones. Torbat-e-Jam granitoid intrusion of Triassic age is the main magmatic display in the district. These plutonic rocks with NW-SE trending intruded Miankouhi Formation (Upper Triassic) consisting of coaly shale, siltstone and sandstone converting those to hornfels for tens of meters around the plutons. Heavy mineral studies resulted in detecting minerals such as gold, scheelite, arsenopyrite, malachite, barite, jarosite, hematite, magnetite, specularite, galena, pyrite and garnet. Stream sediment analysis have shown anomalies of As, Cu, Bi, Co, W, Fe and Ti and a positive relationship between gold and As, Bi and Cu. Further exploration based on systematic sampling of soils around the plutonic rocks through determining statistical parameters for distribution of elements and fitting variogram of logarithmic data, has determined the anomaly threshold and quantified possible and probable anomalies. According to multi-variable statistics and factor analysis, the As, Cu, Au, Co, Fe, Mn and Ti, (W, Sb) package has a meaningful relationship with gold mineralization. The accomplished studies, as well as findings from heavy mineral, stream sediment and soil sampling show an interesting display of As, Au and to some extent Cu anomalies. Secondary dispersion halo maps for gold and its pathfinder elements such as As, Cu and Bi as well as factor analysis and additive index imply a high potential for gold in the Tarikdarreh prospect area.
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Volume 21, Issue 2 (7-2013)
Abstract
The study area is located at the Soghanchi village (east of Miyandoab city, NW of Iran). The Oligocene age Soghanchi stock is intruded into Permian carbonate rocks during Pyrenean orogenic epoch. Petrographically, the main minerals of this intrusive are plagioclase, biotites, pyroxenes, olivines, hornblendes, and alkali-feldspars. The microscopic and geochemical assessments of intrusive, show gabbro-dioritic, monzo-gabbroic and monzonitic composition with high potassic- calc-alkaline to shoshonitic and meta-aluminous characters. Based on this investigation, the Soghanchi pluton has formed in a continental arc setting. Intrusion of this stock into the Permian limestones, results in different degrees of recrystalization and skarnification. The Soghanchi calcic skarn is mainly composed of anhydrous calc-silicates, retrograde metasomatic products, some calcite, and quartz. Magnetite and minor hematite are the main metallic minerals in this area. Physco-chemical investigations showed 450-650oC for skarnification (prograde stages) and 400-450oC for retrograde metasomatic event and iron mineralization.
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Volume 22, Issue 1 (4-2014)
Abstract
The study area is located at northeast of Neyshabour in the Khorasan Razavi Province, northwest Arghash Gold Mine. The rocks of area are composed of polutonic to subvolcanic units with acid- intermediate in composition. They consist of granodiorite, diorite and granite. Alteration zones are: propylitic, sericitic, silicified and argillic. In the study area, mineralization is divided into two types: primary and secondary .The Primary mineralization consists of disseminated type in intrusive bodies (syngentic) and vein-type mineralization in fault zones (epygentic). Pyrite is recognized in dioritic and granitic intrusive as disseminated.The vein- type mineralization consists of chalcopyrite, pyrite, quartz and calcite minerals which are related to NE-SW, NW-SE, E-W fault zones dipping 60 degree. Secondary minerals in the study area are malachite, azurite, hematite, goethite and covellite. Geochemical study in the area shows anomalies for Cu, Pb and Zn in primery and secondary geochemistry halos. High concentration of Cu, Zn and Pb in stream sediments samples are 124, 85 and 38 ppm and in rock samples are 2200, 336 and 589 ppm respectively. Based on present of disseminated mineralization in the surface and undersurface Arghash area, present of vein-type mineralization Au and Sb in the arghash area and present of vein-type mineralization in the fault Zone in the study area, present of geochemistry halos for Cu, Zn, Pb in the study ares and surrounded, probably Arghash area can be vein-type mineralization ralatad to copper porphyry system in this area.
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Volume 23, Issue 2 (7-2015)
Abstract
Keybarkuh is located about 70 Km southwest of Khaf city (Khorasan Razavi Province) in the northeast of the Lut block. Rock units in the area comprises of slate, phyllite, schist and recrystalized limestone with Paleozoic age that was intruded by granite to diorite as dikes and stocks of Cretaceous to Tertiary age. Based on magnetic susceptibility, intrusive bodies are oxidant and reducing which the oxidant bodies mostly having alteration and mineralization. The eastern Keybarkuh oxidant bodies are of Midlle Eocen, related to subduction environment of continental margin, often high-K to shoshonitic and metaluminous. Propylitic alteration zones with broader area and sericitic, argillic and silicic with less distribution were observed in the southern area. Mineralization is seen in the contact of intrusive bodies or in joint and fractures of them as veins and veinlets in south of the area. Veins and veinlets with northwest to southeast strike, 70 to 80 degrees dip to the northeast have thickness upto half meter. They can be divided into two sets: 1-Veins and veinlets associated with galena, sphalerite and barite as primary minerals, which formed the first generation of mineralization. 2- Veins and veinlets associated with pyrite, chalcopyrite and quartz as primary minerals; covellite, bornite, chalcocite, malachite, azurite and iron oxides (magnetite, hematite and limonite) as secondary minerals which is the second generation of mineralization. Paragenetic sequences of minerals and relationship between minerals are indicative of a hydrothermal activity and deposition of the above mentioned minerals in at least two stages in the upper part of oxidant intrusive bodies. Geochemical exploration of stream sediment show anomalous Cu (68 ppm), lead (1691 ppm), zinc (320 ppm), barium (5003 ppm) and the rock also show anomalous Cu (3%), gold (2657 ppb), silver (ppm 160), lead (4%), zinc (2159 ppm), barium (1466 ppm) bismuth (1767 ppm) and Mo (66 ppm) in the southern parts of the area which are relatively high.
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Volume 23, Issue 4 (1-2016)
Abstract
Shelgerd area is located south of Mashhad, N.E of Iran, within Binalud Structural Zone. This region is affected by regional metamorphism, slate and phylite are the main metamorphic rocks of the area. Teriassic slate, phyllite, sandstone and Jurassic conglomerates crop out parallel to Sang bast- Shandize fault. Mineralization occurred as vein type, with trend of N65E to N50W with 75 degrees to the south west. In superficial zones slags are common. primary ores are quartz, pyrrhotite, chalcopyrite, galen, orpiment, realgar and secondary minerals are malachite, azurite, covellite, goethite, hematite, limonite and covellite. Stream sediment geochemical sampling method shows anomalities of Ag, Cu, Pb, Zn, Fe elements. In The heavy mineral samples, some mineral such as orpiment, realgar, gold, pyrite and cassiterite are recognized. Also, geochemical analysis conducted on the small rock samples from surface of gold veins and old tunnel show the amount of gold is about 4.424 ppm, silver 8.42 ppm, copper %4.4964, iron %1.4349, laed %0.6939, and zinc %0.2825. Chemical analysis of galena shows high concentration of Ag, Sb, Bi. Depends on the ratio of Sb/Bi, mineralization temperature is low to medium and epigenetic type. According to mineral galena, crystals are the primary type.
Mohammadreza Kazempour, Mohammadreza Hidarian Shahri, Azadeh Malekzadeh Shafaroudi,
Volume 27, Issue 2 (7-2019)
Abstract
Freezi Lead- Zinc- Copper prospect area is located in north east Mashhad in Khorassan Razavi Province. Mineralization was formed in the area as vein type in the host rocks of slate with interlayer of phyllite and meta sandstone of Upper Triassic to Early Jurassic age (equivalent to Shemshak Formation). The only alteration in the host rock is silicification. Primary minerals are quartz, galena, chalcopyrite and pyrite, while secondary minerals are hematite, goethite, limonite, malachite and azurite. The amount of Pb is up to %3.7, Zn is up to %1.6, Cu is up to %4 and Ag 183 ppm. Micro thermometry measurements of two Phases (liquid and vapour) showed that quartz and ores originated from a fluids with mid to high temperature (200 to 347°c) and high salinity (20.2 to 22.35 wt%) which was probably metamorphic liquid. Reduction of temperature of the liquid had greatest importance in Pb, Zn, and Cu mineralization. IP/RS data on the location of Gossan zones, veins, previous digging, and geochemical anomalies showed increasing in chargeability. Mineralization occurred in three part (A, B, C) in the area. In view of mineralization, geochemical anomalies and chargeability in the part B is more important than A and C. Studies of drill cores over the psedousection IP/RS anomaly in part B showed the presence of graphitic coal in the country rocks which is the causative source of anomaly. Based on geology, mineralization and fluid inclusion characteristics, the type of mineralization in the Freezi area is orogenic. Possibly metallic elements originated from the graphitic layers and during the Middle Jurassic orogenic phase, middle Cemmerian, transported by metamorphic water and deposited in places of suitable structure.
Alipour, Abedini, Alipour,
Volume 28, Issue 3 (10-2020)
Abstract
The Avin kaolin deposit is located about 35km of northeast of the Mianeh town, East-Azarbaidjan Province, NW Iran. Field evidence and petrographic studies indicate that development and formation of this deposit is genetically related to alteration of dacite rocks of Eocene- Oligocene age. In attention to mineralogical data, this deposit consists of minerals such as kaolinite, quartz, muscovite-illite, cristobalite, rutile, orthoclase, and goethite. Investigation of some geochemical parameters such as values of TiO2, Ba+Sr, and Ce+Y+La show that development of this deposit is related to function of two processes of hypogene and supergene. Incorporation of the obtained results from mineralogical studies, mass changes geochemistry, and variations trend of elemental ratios indicate that chemistry of altering fluids (pH and Eh), surface adsorption, scavenging by metallic oxides, fixation in neomorphic mineralogical phases, ratio of fluid to rock, and amount of availibility to complexing ions are six effetive parameters in mobilization, distribution, and enrichment of trace and rare earth elements in this deposit. Geochemical analysis indicates that decrease of Eu anomalies in kaolinized samples was related to destruction of plagioclase minerals of the dacitic rocks by high temperature hydrothermal fluids and decrease of negative Ce anomalies is due to development of kaolinization process by fluids with acidic-oxidizing nature.
Nakhjavani, Calagari, Alavi, Siahcheshm,
Volume 29, Issue 2 (6-2021)
Abstract
The copper skarn deposit at Gowdal is located in northeast of Shivardagh batholithic body, north of Ahar, East-Azarbaidjan Province. The Shivardagh intrusive body is a part of the magmatic belt of the Alborz-Azarbaidjan-Lesser Caucasus which in turn is related to the magmatic arc of the Meso-Tethys Ocean. The skarn mineralization of copper, iron, and molybdenum (chalcopyrite, pyrite, molybdenite, magnetite, and specularite) occurred particularly in exo-skarn zone at the contact of this igneous body with limestone- marly limestone unit. Also, the supergene copper-iron minerals (malachite, azurite, and Fe-hydroxides) superimpose the hypogene skarn mineral assemblages. Based upon statistical studies carried out on the data obtained from core logs, copper has very good correlation with silver and good correlation with gold and nickel and these elements are reckoned to be as elemental paragenesis in the Gowdal ore body. In addition, consideration of multiplicative geochemical haloes of elements in the supra-ore (Pb×Zn×Sb) and sub-ore (Cu×Ag×Ni) showed that the greater and more notable haloes of supra-ore elements belong to the near-surface horizons while the bigger haloes of sub-ore elements are observed in the lower horizons of the ore body. The function of erosion in the southwest of deposit caused the ore body to be situated in its present level, and the ore body displays the evidence of hidden mineralization toward northeast. On the other hand, considering the minimum and maximum values of the geochemical zonality indices (0.0016-27) in the present level and the elevation levels of the boreholes, the ore body has a northeastward dip.
Alaminia, Sheikhi, Razavi,
Volume 29, Issue 3 (9-2021)
Abstract
Baghche-Maryam granitoid (in south of Ghorveh Area) is a part of the intrusive bodies of the Sanandaj-Sirjan zone with NW-SE trending. Based on field observations and mineralogical studies, the intrusion complex of Baghche-Maryam including of two acidic and intermediate units: diorite, monzodiorite, granite, syenite, and aplite. Geochemical studies show the rocks of this complex are metaalumine type (A/CNK= 0.81-0.46) and calc-alkaline. Petrological, mineralogical, and geochemical studies together with field observations indicate that these rocks are generated by various magmatic processes and are related to the active continental margin geodynamic environment (e.g. LREE enrichments and HREE depletions) and have I-type magmatic characteristics. According to thermobarometery studies, the average temperature in the studied samples is about 700 oC and the average depth is about 7-10 kilometers.
Ebrahim Tale Fazel,
Volume 31, Issue 4 (12-2023)
Abstract
Investigation of geochemical-metallogenic conditions and mineralogy of the supergene, oxidation, mobilization, fractionation, and reprecipitation of metals, is fundamental for the understanding of the genesis of non-sulfide Pb-Zn deposits. The Changarzeh Pb-(Ag) deposit is located about 75 km northeast of Esfahan Province, within the southern Malayer-Esfahan metallogenic belt. Middle Triassic breccia-dolostone is the main mineralization host rock, and has two hypogene (sulfide) and supergene (oxide, carbonate, and silicate) ores. Frequent minerals of the supergene ore include smithsonite, hemimorphite, hydrozincite, anglesite, and cerussite. Metal separation is caused by a gradual changes from an acidic oxidation zone to alkaline conditions in the adjacent carbonate wall rock. The formation of an acidic oxidation zone within carbonate host rocks is facilitated by the “armouring” of galena by anglesite and by several pH-buffering reactions. The high activity of sulfuric acid-related SO42- ions during the oxidation stage led to the precipitation of highly insoluble anglesite, which results in low Pb2+ concentration within the fluid. Generally, limited availability of meteoric water and deep-water tables protect the non-sulfide ore from subsequent dissolution, where these conditions played an important role in the understanding on trcaing of non-sulfide supergene deposits.