Economic Geology
Mahdi Ghorbani- Dehnavi; Azadeh Malekzadeh -Shafaroudi; Mohammad Hassan Karimpour
Abstract
Chah-Nar Pb-Zn deposit is located south of Rutchun plain, 110 km SW Baft, within Sanandaj- Sirjan Zone. Mineralization occurs at calitic-dolomitic marble of Rutchun complex as epigenetic with structural control. Paragenetic minerals are galena and minor sphalerite and pyrite associated with ...
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Chah-Nar Pb-Zn deposit is located south of Rutchun plain, 110 km SW Baft, within Sanandaj- Sirjan Zone. Mineralization occurs at calitic-dolomitic marble of Rutchun complex as epigenetic with structural control. Paragenetic minerals are galena and minor sphalerite and pyrite associated with quartz, and minor calcite and dolomite, as gangue minerals. These minerals show veinlets, open space filling, breccia, and disseminated textures. Galena can be seen in the form of coarse grain crystal and cuboctahedral texture and fine grain crystal. Silicification and carbonatization are the most important alteration zones. Galena chemistry indicates galena is Ag, As, Cd and Zn -rich and Sn, Bi-poor. Sb/Bi ratio in galena is close to 3, which is indicator of low temperature deposits. Host rock type, stratabound and epigenetic mineralization, postsedimentary fault controlling, texture, ore types and gangue minerals, and lack of significant correlation between mineralization and igneous activities, chemistry of galena, indicate that Chah-Nar deposit is similar to MVT deposits, although it has some differences with this deposits type.
Economic Geology
Maryam Javidi Moghaddam; M.H Karimpour; Azadeh Malekzadeh Shafaroudi
Abstract
The Rashidi area, which comprises a part of the north Khur in eastern Iran is located at 120 km northwest of Birjand city. Preliminary prospecting in the area using the image processing of ASTER data by Spectral Angle Mapper (SAM) algorithm resulted in the identification of propylitic and argillic alteration ...
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The Rashidi area, which comprises a part of the north Khur in eastern Iran is located at 120 km northwest of Birjand city. Preliminary prospecting in the area using the image processing of ASTER data by Spectral Angle Mapper (SAM) algorithm resulted in the identification of propylitic and argillic alteration zones together with iron oxy-hydroxide minerals. The area consist of outcrops of Eocene pyroclastic rocks ranging from andesitic to rhyolitic in composition, intruded by diorite porphyry dikes. Vein mineralization in the area was mainly occurred along a fracture system hosted by andesitic tuff breccia unit. Vein copper mineralization was formed during two stages including the: (1) quartz-pyrite-chalcocite-tennantite assemblage, and (2) quartz-chalcocite-pyrite-sphalerite assemblage. The values of δ18O for quartz in the first and second stages of vein mineralization was 19.26 and 14.94 and the amount of δ18O water in equilibrium with quartz was 10.96 and 4.94 respectively that shows a magmatic origin and mixing with meteoric water in the second stage. Based on geology, vein geometry, fluid inclusion, and stable isotope geochemistry, the Rashidi Cu deposit can be classified as vein-type copper deposits, which has been formed along fault zones.
Economic Geology
Hossein Abasnia; M. H. Karimpour; Azadeh Malekzadeh Shafaroudi
Abstract
Damanghor area is located northern Bardaskan, Khorasan Razavi province, and structurally, it is a part of Taknar zone. Geology of the area includes of Taknar metamorphosed sedimentary rocks and metarhyolite, which is intruded by diabasic rocks as stoke and dyke. The texture of metarhyolies is porphyry ...
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Damanghor area is located northern Bardaskan, Khorasan Razavi province, and structurally, it is a part of Taknar zone. Geology of the area includes of Taknar metamorphosed sedimentary rocks and metarhyolite, which is intruded by diabasic rocks as stoke and dyke. The texture of metarhyolies is porphyry and contains of quartz and feldspar, whereas diabas has ophitic texture and contain plagioclas, pyroxene, and hornblend. Age of metarhyolite and diabas determined 550 Ma (Neoprotrozoic) and 8.8 Ma (Miocene), respectively, using zircon U-Pb method. Metarhyolites have peraluminous nature and were formed at intracontinental rift. Low enrichment in LREE relative to HREE and Eu negative anomaly indicates the magma is formed at plagioclase stability depth. (87Sr/86Sr)i (0.700712), (143Nd/144Nd)i (0.511852), and εNdi (–1.51) values show source of magma was mantel or lower crust. Diabases have toleitic to metaaluminous nature and were formed at subduction zone. (87Sr/86Sr)i (0.710527), (143Nd/144Nd)i (0.512716), and εNdi (+1.7) values indicate magma is drived from partial melting of metasomatized mantle wedge by released fluid of subducted slab, which is assimilated with continental crust. Taknar formation acidic Neoprotrozoic magmatism, which is formed at rift setting, associated with Miocene basic magmatism, which is formed at subduction zone, reveals an insight of tectonomagmatic conditions of Taknar zone in different times.
Pooneh Eshbak; Azadeh Malekzadeh Shafaroudi; Mohammad Hassan Karimpour
Abstract
Jalambadan area is located northwestern Sabzevar, Khorasan Razavi province, and southwestern Quchan-Sabzevar magmatic belt. Geology of the area includes of andesitic-trachyanesitic volcanic rocks, which is intruded by monzodioritic to dioritic subvolcanic intrusive rocks. The texture of igneous rocks ...
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Jalambadan area is located northwestern Sabzevar, Khorasan Razavi province, and southwestern Quchan-Sabzevar magmatic belt. Geology of the area includes of andesitic-trachyanesitic volcanic rocks, which is intruded by monzodioritic to dioritic subvolcanic intrusive rocks. The texture of igneous rocks is porphyry and the main minerals are plagioclase, alkali fldespar, pyroxene, hornblende, and magnetite. Age of intrusive rocks determined 44.7 to 45.2 Ma (Middle Eocene-Lutetian), using zircon U-Pb method. Geochemically, igneous rocks of the area are calc-alkaline and were formed at subduction zone. Relativelly, enrichment in LREE relative to HREE and enrichment of K, Rb, Cs, and Sr relative to Ti and Nb elements are observed in all of samples. Eu anomaly and Sr/Y ratios can be attributed to the presence of residual plagioclase and a few garnet in a source. (87Sr/86Sr)i (0.703708 to 0.704444), (143Nd/144Nd)i (0.512858 to 0..512933), and εNd I (5.42 to 6.88) values of intrusions and geochemical signatures of volcanic rocks indicate magma is drived from partial melting (7-5% for intrusions and 15-25% for volcanic rocks) of spinel lherzolite mantle wedge above subducted slab, which is assimilated slightly with upper continental crust very little.
Economic Geology
Hakima Taghadosi; Azadeh Malekzadeh Shafaroudi
Abstract
Namegh area is located northeastern Kashmar, Khorasan Razavi province, and centeral part of of Khaf-Kashmar-Bardaskan magmatic belt. Geology of the araea is covered by Eocene volcanic rocks having andesite to rhyolite composition, which are intruded by subvolcanic intrusions with monzonite, monzodiorite, ...
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Namegh area is located northeastern Kashmar, Khorasan Razavi province, and centeral part of of Khaf-Kashmar-Bardaskan magmatic belt. Geology of the araea is covered by Eocene volcanic rocks having andesite to rhyolite composition, which are intruded by subvolcanic intrusions with monzonite, monzodiorite, and diorite composition. All of units are affected by well development alteration, which are silicified-sericitic, moderate argillic, and propylitic alteration zones. Mineralization is occurred as stockworck and disseminated. Primary minerals include chalcopyrite, pyrite, magnetite, and gold and secondary minerals include goethite, hematite, malachite, and azurite. High anomaly of Cu (up to 1%) and Au (up to 12 ppm) are correlated with strong silicified-sericitic alteration. Based on fluid inclusion studies, formation temperature of mineralization is between 404 to 551 ºC and it is occurred from NaCl-, and CaCl2-bearing fluid with 15 to 23 wt. % NaCl equivalent salinity. Decrease of temperature and HCl activity during boiling time and decrease of temperature due to mixing of magmatic and meteoric fluids could be the most important factors for formation of mineralization. Evidences of tectonic setting, lithology, development and types of alteration, mineralization form and limited outcrops, types of ore minerals, geochemical anomalies, types of fluid inclusions and temperature and salinity of fluid indicate the mineralization of Namegh is probably upper level of porphyry Cu-Au deposit. The Khaf-Kashmar-Bardaskan belt can be one of the most important porphyry deposits metallogenic zones of Iran due to tectonic setting and magmatic-mineralization evidences, which needs detailed exploration in future.
A Hosseinkhani; M.H Karimpour; A Malekzadeh Shafaroudi
Abstract
The SW Sorkh-Kuh area makes part of the Tertiary volcanic-plutonic rocks in the west of the Lut Block, SW of Birjand city. Geology of this area consists of andesitic and basaltic volcanic rocks intruded by hornblende diorite, hornblende microdiorite, hornblende diorite porphyry, hornblende quartz diorite ...
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The SW Sorkh-Kuh area makes part of the Tertiary volcanic-plutonic rocks in the west of the Lut Block, SW of Birjand city. Geology of this area consists of andesitic and basaltic volcanic rocks intruded by hornblende diorite, hornblende microdiorite, hornblende diorite porphyry, hornblende quartz diorite porphyry and biotite quartz monzonite, which caused extensive alteration and mineralization. The vein mineralization with a NW-SE trend have been observed in the NW portion of the area which is composed of quartz, chalcopyrite, pyrite and Fe-Cu secondary minerals. This vein is the youngest occurrence of mineralization, related to intrusive rocks, in the Lut Block (after Miocene). Primary fluid inclusions of quartz in paragnesis with mineralization, revealed three types of two phases inclusions with difference in density, which liquid rich phases have an average 270 and 330°C of homogenization temperature. Based on freezing studies, calculated temperature of last melting point of these fluids equals to 12-15 and 16-19% wt eq. NaCl, respectively. Some fluids, which homogenized to gas, have more homogenization temperature and salinity. In evaluation of depth, using homogenization temperature, salinity, density and pressure of fluid inclusion, 700 m depth was calculated for mineralization, corresponding to the present erosion surface. δ18O values of quartz in mineralized vein and fluid in equilibrium with quartz have a range between +8.66 – +13.09‰ and +3.06 – +7.59, respectively. It could be inferred that the source of ore-forming fluids was magmatic in the mineralized vein. In general, stable isotope and fluid inclusion studies show similarity of mineralization of the SW Sorkh-Kuh with epithermal deposits in which mineralization is related to the dioritic intrusive rocks. The changes in fluid composition and boiling resulted in mineraliztion along a fault as vein.
N Mazhari; A Malekzadeh Shafaroudi; M Ghaderi
Abstract
The Senjedak-I prospect area is one of the six eastern anomalies of Sangan iron mine. Geologic units in the area consist of Jurassic shales and sandstones, skarn rocks and Tertiary biotite monzonite and biotite syenogranite intrusive rocks. Due to the severe alteration of biotite monzonite porphyry intrusive, ...
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The Senjedak-I prospect area is one of the six eastern anomalies of Sangan iron mine. Geologic units in the area consist of Jurassic shales and sandstones, skarn rocks and Tertiary biotite monzonite and biotite syenogranite intrusive rocks. Due to the severe alteration of biotite monzonite porphyry intrusive, geochemical studies have focused on the biotite syenogranite.
This granular intrusive consists of alkali feldspar, plagioclase, quartz, biotite and accessory minerals such as zircon, sphene, apatite and magnetite, with weak sericitic, argillic and silicic alteration. Biotite syenogranite rock is rich in silica (68.7 to 77.2 wt.%) and is chemically peraluminous and has generated by fractional crystallization from an I-type granitic magma poor in P (average 0.1% P2O5). This intrusive rock falls in the range of I-type granites and is oxidized. REE values indicate negative Eu anomaly, mild enrichment of LREE, a positive pattern close to flat HREE, negative anomalies of Ba, Sr, La, Ce, Ti, and Eu. On the basis of Rb, Nb, Yb, Hf, and Ta, tectonic setting of samples fall in Volcanic Arc Granite (VAG) and Post Collision Granite (post-COLG) divisions.
The most important event in Senjedak-I area is the penetration of Fe-bearing fluids in carbonate rocks, their recrystallization, skarnification (prograde and retrograde), and iron ore deposition that could be explained by the occurrence of calc-silicate minerals.
The skarn has been separated into 4 zones on the basis of abundance of the calc-silicates: garnet skarn, phlogopite skarn, epidote skarn, and amphibole skarn.
According to Electron Probe Micro Analysis (EPMA), the composition of garnets is andradite-grossular (An 100-42.6 Gr 0-55.32 Sps 0-1.39) and pyroxenes are diopside-hedenbergite (Di 63-92 Hd 4-35 Jo 0.5-3.9).
Mineralization in this prospect area formed as stratabound and massive bodies in the carbonate rocks. The main ore mineral is magnetite (40%) with minor amounts of pyrite. Secondary minerals are hematite and malachite. The FeO in the magnetite is 91.7% and the S content is 0.03%. The Senjedak-I anomaly places along the eastern part of Dardvay deposit (in central division of Sangan mine) and the geochemical similarities of intrusive rocks, chemistry of skarn minerals, and pyroxene and garnet composition confirms that the Senjedak-I is a part of Dardvay, which is separated by a main fault with southeast-northwest trend.
A Askari; M.H Karimpour; S.A Mazaheri; A Malekzadeh
Abstract
The Hired gold prospect area is located in the Southern Khorasan province and 140 Km south of the Birjand city. The Acidic to mafic intrusive bodies with gabbro to granite composition have intruded into the Tertiary volcano-sedimentary sequences. Based on magnetic susceptibility, the intrusives are divided ...
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The Hired gold prospect area is located in the Southern Khorasan province and 140 Km south of the Birjand city. The Acidic to mafic intrusive bodies with gabbro to granite composition have intruded into the Tertiary volcano-sedimentary sequences. Based on magnetic susceptibility, the intrusives are divided into two categories: magnetite (oxidized) and ilmenite (reduced) series. The important alterations recognized on land surface and bore holes consist of: 1) quartz-tourmaline-sericite alteration, 2) carbonation alteration, 3) skarnization, and 4) propylitic alteration. Au and accompany elements mineralization (W, Sn, Bi, As, Sb, Pb, Zn, Ag) have formed as replacement, disseminate, vein-veinlet, massive, breccias, and skarn related to reduced granitic-granodioritic intrusive bodies and with different distance as compared with the bodies. Geological, mineralization, petrographical, mineralogical and alteration studies of the Hired gold deposit and comparison with the characteristics of different types of gold mineralization in the world indicate that this deposit has the most similarity with reduced intrusion-related gold systems (RIRGS). Since In this system, the most of gold reserve is accompanied with sulfide minerals and they form in roof of the reduced granitoid stocks and adjacent hornfels rocks, The IP- RS geophysical methods on reduced granitoid intrusive body and near regions was executed with the aim of recognition of hidden parts. Combination of geophysics data (IP, RS) with geological, alteration, and mineralization studies shows well development mineralization in the east of intrusive body and the country rocks. In this relation, 6 anomalous regions has been defined with Chargeability up to 30 mv/v that on the whole, they can be divided into two groups: 1) anomaly with high induced polarization and low specific resistivity resulting from presence of much metallic sulfurs as disseminate, veinlet, and massive accompanied with high sericitic alteration, 2) anomaly with high induced polarization and medium-high specific resistivity resulting from presence of much metallic sulfurs as disseminate and very high carbonation-silicic alteration.
R Ahmadi Rohany; M.H Karimpour; B Rahimi; A Malakzadeh Shafaroudi
Abstract
The studied area is located in east of BajestanTownship, KhorasanRazaviProvince and this region is a part of the Lut Block. Granite is the most important rock in this area with covering approximately 70km2. Processing of satellite data in this area was done by using of SPOT, ASTER and Landsat ETM+ data. ...
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The studied area is located in east of BajestanTownship, KhorasanRazaviProvince and this region is a part of the Lut Block. Granite is the most important rock in this area with covering approximately 70km2. Processing of satellite data in this area was done by using of SPOT, ASTER and Landsat ETM+ data. SPOT images processing and using PCA methods (standard and selective) on the ETM+ data show this intrusive body doesn't have an equal chemical composition. The central part of the intrusive body has distinctive from margin and it seems that the central part have more mafic mineral. For enhancing linear structure, high pass, directional, threshold and sobel filters were applied separately and compositional on the SPOT data. By using these filters linear structures became completely obvious and were vectorized digitally. The most of them show northwestern-southeastern trend. ASTER data processing by spectral angle mapper (SAM), band ratio and band composition methods enhanced epidote, sericite, hematite, argilic and silicified alterations. Processing and Interpretation of airborne geophysical data (potassium, thorium, uranium and total magnetic intensity), which collected by airplane show the amounts of these triple elements (K,U,Th) are high and in vice versa Total Magnetic Intensity data (TMI) is low in this granite. Separating geological boundaries and enhancing major faults are other results from processing of geophysics data. Merging all of the data consist of: satellite and geophysics data processing and field research indicate alteration zones have relation to linear structures in this area. This research specifies the most probability of mineralization presence in this area so that Fe and Cu mineralization conform to epidotic-chloritic and argilic alterations. Introducing favorable area can help us to concentrate exploration activities and next researches in this area and prevent wasting money and time.
M. H. Karimpour; A. Malekzadeh Shafaroudi
Abstract
Sangan Iron ore deposit is located 300 km southeast of Mashhad (Eastern Iran). Based on the high grade, low P- content and big ore reserve, Sangan is an important Iron mine in Iran. It is a magnetite skarn and can be classified as iron-oxide type deposit. Based on the surface exposure, the western magnetite ...
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Sangan Iron ore deposit is located 300 km southeast of Mashhad (Eastern Iran). Based on the high grade, low P- content and big ore reserve, Sangan is an important Iron mine in Iran. It is a magnetite skarn and can be classified as iron-oxide type deposit. Based on the surface exposure, the western magnetite skarn (A´), a Ca-rich type skarn, was formed at the contact of intrusive. Eastward, the skarn gradually becomes distal and Mg-type. The A´ magnetite skarn contains andradite, magnetite, K-rich amphibole, hedenbergite and calcite. Magnetite skarn in A, B, and C- south contain magnetite, repidolite, ferro-actinolite, siderite and minor pyrite. Baghak and C- north magnetite skarn comprise Mg-rich- magnetite, phlogopite, chinochlore, talc, dolomite, forsterite, dolomite, pyrite ± chalcopyrite ± arsenopyrite ± pyrrhotite. High S-content is found mainly in Baghak and C-north deposits. In this research, the igneous source rock is found in A´ deposit and identified as ultra-potassic type (K2O> %9). Sarnowsar granite which used to be the source rock for Iron, contains less than %5 K2O, therefore it cannot be the source. The K2O content of Sarnowsar granite increases near the magnetite skarn due to alteration. The Fe-ore bearing solution moved along the contact between Sarnowsar granite and the limestone. Sarnowsar granite was altered and skarn formed in the limestone.
The source rock is quartz biotite-hornblende alkali syenite to quartz hornblende syenite porphyry. The younger intrusive rocks are biotite granite, biotite-hornblende quartz monzonite porphyry and quartz syenite porphyry. Potassium within the ore bearing solution controlled the mineralogy of skarn. Contact skarn in A´ magnetite deposit comprises K-rich amphibole and distal skarn (Baghak and C-north) contains phlogopite.
Comparison of trace elements from source rocks with Sarnowsar granite indicates that the Nb, Zr, Zn and Rb contents are high in the former rocks and Cu and Sr ones are higher in the latter rock. Furthermore, comparison of some trace elements from source rocks with younger intrusive rocks indicate that Cr, Ni, Zr, Ce, Cu, Sr, and La contents are higher in younger intrusive and Rb content is higher in source rocks.
