Majid Ghsemi Siani | Kharazmi University (original) (raw)

Papers by Majid Ghsemi Siani

Journal of Geochemical Exploration, 2022

Abstract In this study, the styles, types, and degrees of hydrothermal alteration associated with... more Abstract In this study, the styles, types, and degrees of hydrothermal alteration associated with Pb-Zn-Cu-Ag-Au epithermal deposit systems in the Tarom-Hashtjin metallogenic province are evaluated using petrographic studies, as well as mass changes and molar elements ratios (MER), in order to examine regional exploration implications. The MER plots show that the hydrothermally altered rocks were most affected by various types of K-metasomatism, mainly characterized by K gains and Na and Ca losses. The intensity of K-metasomatism is related to precious and base-metal mineralization, showing increasing K trends toward the ore veins. The alteration index (AI) and chlorite-carbonate-pyrite index (CCPI) reveal that argillic, sericitic, and propylitic alteration types are the main zones of alteration surrounding ore veins indicating that AI increases and CCPI decreases toward more proximal to the structures linked to these ore systems. Determination of mass changes in altered rocks surrounding selected epithermal deposits suggest Si, K, and Al gains and Na and Ca losses increasing in intensity toward ore veins, consistent with alteration zoning from the silicic and K-metasomatic (sericite and argillic) inner zones to the propylitic (Fe-rich chlorite alteration) outer zone typical of epithermal ore systems. Data from this study show that the intensity of K-metasomatism in the acidic rocks is greater than in the intermediate and mafic rocks, where it is related to high to intermediate sulfidation epithermal systems. We suggest that exploration can be focused on highly altered volcanic rocks (especially andesite-dacite) with both high intensity of K-metasomatism and higher Pb, Zn, Ag, Au, Ba and Rb and lower Sr.

Ore Geology Reviews, Nov 1, 2020

Cenozoic magmatism in Iran is associated with many epithermal-porphyry Cu-Au ore systems, which m... more Cenozoic magmatism in Iran is associated with many epithermal-porphyry Cu-Au ore systems, which mainly occur within the Alborz Magmatic Arc and Urumieh-Dokhtar Magmatic Arc systems. The Tarom-Hashtjin metallogenic province in the NW part of Iran is located in the western Alborz Magmatic Arc, and is host to numerous LS-IS and HS-type epithermal deposits within Eocene volcano-plutonic rocks. Whole-rock geochemical data indicate that volcanic rocks vary extensively and continuously from subalkaline basaltic to rhyolitic compositions. Granitoid rocks are characterized by subalkaline, metaluminous to peraluminous, I-to A-type magmatism. Geochemical and geochronological studies of the igneous rocks associated with epithermal deposits, particularly the enrichment of large-ion lithophile elements, depletion of high field strength elements, including Nb-Ta depletion and their Eocene ages, are consistent with extensional back-arc tectonic settings, suggesting that primary source magmas were generated by partial melting of the mantle-wedge (garnet-bearing depleted lithospheric upper mantle) and were subsequently affected by both fractional crystallization and crustal assimilation during their magmatic evolution. The regional magmatism likely contributed to the heat advection and composition of metal-bearing hydrothermal fluids in the formation of the epithermal deposits. Considering strong plagioclase fractionation relative to hornblende fractionation, an extensional back-arc tectonic setting, the lack of any skarn mineralization, and a considerably shallower depth of magma generation, the Tarom-Hashtjin metallogenic province is proposed to be prospective for precious metal epithermal mineralization. By contrast, the Urumieh-Dokhtar Magmatic Arc and Ahar-Arasbaran zone systems are probably more eroded and thus more prospective for porphyry Cu-Au exploration. concentrated in the Alborz Magmatic Arc (AMA) in the north, Urumieh-Dokhtar Magmatic Arc (UDMA) parallel to the Sanandaj-Sirjan zone (SSZ), and the Central-East Iran (Fig. 1). Many epithermal-porphyry deposits worldwide hosted by potassic and shoshonitic igneous rocks related to arc and back-arc magmas in subduction settings, which favor the generation of magmas under oxidizing conditions (

Research Square (Research Square), Jul 18, 2023

Based on new Sr-Nd-Pb isotope-compositional and lithogeochemical data combined with previously pu... more Based on new Sr-Nd-Pb isotope-compositional and lithogeochemical data combined with previously published data of the Kahnouj ophiolite, we propose a tectonic model for the Kahnouj ophiolitic complex. The Kahnouj ophiolitic complex is the largest ophiolite of the Makran zone and consists of isotropic and layered gabbros with ultrama c lenses at the bottom and sheeted dikes, and basalts and pelagic limestones on the top. A cyclic succession of isotropic and layered gabbros indicates a distinct differentiation trend of early clinopyroxene crystallization followed by hornblende. Crystal fractionation and partial melting processes are also inferred by Nd isotopic and whole-rock geochemical data (e.g., fractionation recorded by the Al 2 O 3 /TiO 2 versus Ti/1000 diagram). Geochemically, the gabbros are subalkaline and show tholeiitic features. The εNd values of + 7 to + 7.6 and initial 87 Sr/ 86 Sr ratios of 0.70352 to 0.70377 indicate a mid-ocean ridge mantle source for the gabbroic rocks. The whole rock geochemistry of the layered and isotropic gabbros suggest that they formed in a back-arc basin setting and represent MOR-to supra-subduction type ophiolites in the Neotethys Ocean during Jurassic to Early Cretaceous (156 to 121 Ma).

مجله بلورشناسی و کانیشناسی ایران, Apr 1, 2022

مجله بلورشناسی و کانیشناسی ایران, Mar 1, 2020

Dardvey iron skarn ore deposit is located in the central part of the Sangan mininig area, northea... more Dardvey iron skarn ore deposit is located in the central part of the Sangan mininig area, northeastern Iran. In this study, silicate geothermometr were used to estimate the formation temperatures of skarn zones in Dardvey Fe-skarn deposits. The main metamorphic minerals in prograde and retrograde skarn zones are garnet-clinopyroxene-tremolite/actinolite-amphibolechlorite-epidote-feldspar-phlogopite-dolomite. Two feldspar geothermometry indicate that endoskarn zone in Sarnowsar granite form at temperatures between 635 to 725 °C, which is not consistent with fluid inclusion tempertures. Based on clinopyroxene-garnet geothermometry, temperature of 300 to 505 5C was calculated for prograde skarn stage. Chlorite and Caamphibole geothermometry of retrograde zone indicates temperature of 200 to 290 °C and 200 to 300 °C respectively. Silicate minerals geothermometry of prograde and retrograde skarn zones are in accordance with fluid inclusion data. Both geothermometery methodes of prograde and retrograde skarn zones indicate that contact metamorphic sakarn development occuured in <600 5C that is consistent with hornblende hornfels facies.

فصلنامه علمی-پژوهشی علوم زمین, Jun 1, 2016

Arabian Journal of Geosciences, Jul 1, 2021

Shallow subsurface geology and Vs characteristics of sedimentary units through out Rasht city Ira... more Shallow subsurface geology and Vs characteristics of sedimentary units through out Rasht city Iran BEHZAD MEHRABI , ANNALS OF GEOPHYSICS

Arabian Journal of Geosciences, Oct 27, 2018

The Garau Formation in western Iran is a potential shale gas play. To evaluate its gas potential,... more The Garau Formation in western Iran is a potential shale gas play. To evaluate its gas potential, a geochemical, geological, and petrophysical study was conducted on samples from the Baba Ghir 1 well drilled in Lurestan District (W Iran). Organic matter analysis of Garau Formation shows that total organic carbon (TOC) ranges between 0.42 and 2.43 wt% and this formation possesses kerogen type III with a high degree of maturity, reflecting gas window conditions. Mineralogical analyses show that the lithology of Garau Formation in this well is carbonate-dominated and the clay mineral content is less than 4%, and displays several characteristics that are similar to the Eagle Ford shale. Based on the relationship among quartz, carbonate, and clay minerals, the brittleness index is about 25%, a value of importance to select the best stimulation fluid. Petrophysical evaluation shows a porosity of about 5-15%. Estimation of the amount of free gas reserves possesses a good correlation with the reserves that were estimated based on petrophysical interpretation. Because of absence of underground contour maps, calculation of adsorbed gas volumes was not possible but estimates of gas storage capacity (G C) shows an increase with depth. All data indicate that the Garau Formation can be considered as a promising gas shale play.

Open Geosciences, Aug 14, 2015

Eocene to Oligocene volcano-plutonic rocks are widespread throughout NW Iran. The Tarom-Hashtjin ... more Eocene to Oligocene volcano-plutonic rocks are widespread throughout NW Iran. The Tarom-Hashtjin metallogenic province is one of the most promising epithermal-porphyry ore mineralized districts in NW Iran. The Glojeh gold deposit, located in the center of this province, is a typical high to intermediate sulfidation epithermal system, spatially and temporally associated with a granite intrusion and associated high-K calc-alkaline to shoshonitic volcano-plutonic rocks. The intrusive complexes of the Glojeh district are characterized by: SiO 2 contents of 60.9 to 70.7 wt.%, K 2 O+Na 2 O of 7.60 to 8.92 wt.%, and K 2 O/Na 2 O ratios of 0.9 to 1.8. They are enriched in light rare earth elements (LREEs), and large ion lithophile elements (LILEs), depleted in high field strength elements (HFSEs), and have weak negative Eu anomalies (Eu/Eu*= 0.5 to 0.9). 40 Ar/ 39 Ar geochronology applied to biotite and feldspar, separated from two intrusives (Goljin and Varmarziar), and two feldspar aliquots separated from hydrothermal veins at North Glojeh and South Glojeh, was carried out to constrain magmatic and hydrothermal events. Plagioclase (± sericite), from North Glojeh and South Glojeh produced ages (42.20±0.34 Ma, and 42.56±1.47 Ma respectively) that overlap with the age of the Goljin intrusion (41.87±1.58 Ma). Geochemical data for the volcano-plutonic rocks in the Glojeh district, that have87Sr/86Sr isotopic compositions that range from 0.706344 to 0.708331, suggest an origin involving partial melting of a depleted mantle source during Neo-Tethyan subduction.

Journal of Asian Earth Sciences

International Journal of Earth Sciences

Pegmatite dikes in the Malayer–Boroujerd–Shazand magmatic complex, located in the Sanandaj-Sirjan... more Pegmatite dikes in the Malayer–Boroujerd–Shazand magmatic complex, located in the Sanandaj-Sirjan zone of the Zagros orogen, are hosted in both granitoid rocks and their contact and regional metamorphic aureoles. In this study, we report the geochronology, geochemistry and mineral chemistry of these pegmatite dikes. The granitoid rocks in the Malayer–Boroujerd–Shazand magmatic suites are mainly monzogranite, quartz diorite, granodiorite and quartz monzonite characterized by metaluminous to peraluminous I-type compositions of the calc-alkaline series and display the geochemical characteristics of volcanic arc granites related to an active continental margin. The pegmatite dikes mainly consist of quartz, feldspar (albite and orthoclase), tourmaline, muscovite and less common biotite and garnet. The tourmaline content in the igneous-hosted pegmatite dikes is higher than those of metamorphic rocks, whereas the muscovite content is lower in the igneous-hosted pegmatite dikes. The K/Rb ratio and the Rb content of pegmatite dikes and their minerals (K-feldspar and muscovite) indicate that they are less evolved. Pegmatite dikes display a typical calc-alkaline affinity of I-type granites and are classified as peraluminous Lithium-Caesium-Tantalum (LCT) family (barren sub-type) to muscovite class. The tourmaline is a schorl-foitite type, which is common in the early crystallization stage of less evolved pegmatites. U–Pb zircon dating of the Boroujerd and Shazand pegmatite dikes yield weighted mean 206Pb/238U ages of 160.2 ± 1.8 and 121.8 ± 1.5 Ma, respectively. In contrast, U–Pb zircon dating of the Malayer pegmatite dike gives a mean 206Pb/238U age of 43.2 ± 1.5 Ma. Our new geochronological data indicate that the first group of pegmatite dikes (older pegmatite dikes) in the Boroujerd district (160.2 ± 1.8 Ma) shows an overlap with the main and first magmatic episode in the Sanandaj–Sirjan zone during Jurassic times, simultaneous with the Middle Cimmerian Orogenic phase, and formed during the subduction initiation. The second group of pegmatite dikes in the Shazand district (121.8 ± 1.5 Ma) formed in the Early Cretaceous and shows a temporal overlap with previously reported ages (ca. 130–114 Ma) during the early Alpine tectonic movements (Late Cimmerian Orogenic phase). Finally, the younger group of pegmatite dikes in the Malayer district (43.2 ± 1.5 Ma) formed in the Eocene overlapping with previously reported ages (ca. 34–52 Ma) which is equivalent to the Laramian phase. These data reveal that the magmatism in the Malayer–Boroujerd–Shazand magmatic complex started in the Early-Middle Jurassic resembling adjacent areas in the Sanandaj–Sirjan zone (e.g., Hamedan region) by melting of crustal protoliths in a subduction tectonic setting. The second and third groups of pegmatite dikes formed during the late subduction to syn-collisional process, respectively. These pegmatite generation marked the subduction initiation to syn-collisional span in the region. The zircon geochemistry (negative Ce anomalies and positive Eu anomalies) is indicative of the relatively oxidized conditions of the parent magma and shows characteristics of continental crust zircon.

فصلنامه علمی-پژوهشی علوم زمین, Dec 1, 2014

Journal of Economic Geology, 2010

The Cheshmeh Hafez polymetal deposit is located in Troud – Chahshirin mountain range in Southeast... more The Cheshmeh Hafez polymetal deposit is located in Troud – Chahshirin mountain range in Southeastern Damghan. In this province, the volcanism and associated mineralization are closely related to major faults Anjilo and Troud with NW-SE trend. The exposed rocks in the study area consist of volcano clastic sequence of sandstone, tuff, volcano breccias and mostly andesitic and andesitic- basalt flows at Cheshmeh Hafez district. Alteration in Cheshmeh Hafez area is consisting of Proplilitization, Sericitization, Argillic alteration and Silicification. Mineralization occurred in three district stages; 1) quartz, carbonate with early pyrite and chalcopyrite assemblages; 2) the main stage of sulfide deposition, comprises early euhedral galena followed by galena and sphalerite, then galena, chalcopyrite, tetrahedrite, pyrite, bornite and digenite, and 3) quartz and calcite barren veins with minor pyrite and chalcopyrite. The average assays from 12 samples of Cheshmeh Hafez veins are; 0.15 g...

Kharazmi Journal of Earth Sciences, Apr 1, 2019

Ore Geology Reviews, 2022

The Ti- Fe mineralization in the Bafq 15 anomaly is located in 35 Km NW of Bafq city, and is part... more The Ti- Fe mineralization in the Bafq 15 anomaly is located in 35 Km NW of Bafq city, and is part of Poshte Badam Block in the central Iran. The syngenetic Fe- Ti mineralization was hosted by gabbro and pyroxenite intrusions. Mineralization is including magnetite, titanomagnetite, ilmenite and minor pyrite. Based on the whole rock chemistry, FeOt, TiO2, CaO, Ni Cr and V show positive correlation with MgO, whereas Al2O3, Na2O+K2O and SiO2 show negative correlation. These correlations are in agreement with crystallization of clinopyroxene, amphibole, plagioclase and oxide minerals in intrusion. The positive correlation of V, Cr and Ni with Fe indicates concentration of these elements in Fe minerals. The chemical composition of ore minerals mostly plots in the solid solution of magnetite- ulvospinel (titanomagnetite) and magnetite- ilmenite fields. In QFM+1> conditions, the high Fe-Ti contents along high H2O content (>2 Wt. %) of parental magma are the most prominent factors cont...

Researches in Earth Sciences, 2020

Ore Geology Reviews, 2021

Abstract The Sangan mining district, with a proven reserve of 1 Gt of 35 to 60% iron, is a world-... more Abstract The Sangan mining district, with a proven reserve of 1 Gt of 35 to 60% iron, is a world-class iron ore district in Iran, and located in the far eastern part of the Cenozoic Alborz Magmatic Arc. The east-west trending Sangan mining district consists of fourteen iron deposits, spatially associated with the Eocene Sarnowsar composite intrusion (syenite to syenogranite and granite), subvolcanic (quartz monzonite and syenite) and volcanic rocks (andesite and rhyolite). Syenogranite and quartz monzonite rocks in the Dardvay skarn are classified as oxidized I-type granites, with an average SiO2 content of 69.25–65.91 wt.%, Al2O3 content of 13.71–13.98 wt.%, total alkali (Na2O+K2O) content of 8.55–8.02 wt.%, respectively. LA-ICP-MS zircon U-Pb dating on three syenogranite samples yield U-Pb ages of 39.6 ± 0.7 Ma, 39.3 ± 0.3 Ma, and 39.1 ± 0.4 Ma, whereas two zircon samples from skarn zones yield U-Pb ages of 39.7 ± 0.4 Ma and 39.5 ± 0.4 Ma, indicating a Middle Eocene mineralization event closely related to the Sarnowsar syenogranite. Zircon grains from a host rhyolite yield a U-Pb isochron age of 40.2 ± 0.4 Ma and previous published age for quartz monzonite is 42.3 ± 0.8 Ma. The Dardvay deposit is developed along the contact of the Sarnowsar syenogranite with dolomitic limestone with distinct exoskarn and endoskarn zones. The endoskarn zone is limited in extent, whereas the exoskarn is more extensive and includes pyroxene and garnet skarn zones close to the Sarnowsar syenogranite and epidote-phlogopite-actinolite skarn distal to it. The composition of clinopyroxenes plot along the diopside-hedenbergite join in the diopside and augite fields. The garnet composition ranges from Ad60Gr38 to Ad40Gr59. Three main paragenetic stages of skarn formation and ore deposition have been recognized at the Dardvay deposit: (1) a prograde stage developed at 380° to >550 °C with a fluid salinity between 16 and 66 wt.% NaCl equivalent, (2) a retrograde stage which formed at 175°–325 °C with fluid salinity of 2.3 and 33.4 wt.% NaCl equivalent, and (3) a post-ore-stage with quartz veins that developed at 180°–300 °C with salinity range of 8.3 to 17.7 wt.% NaCl equivalent. Oxygen isotope analyses were conducted on magnetite from retrograde stage, resulting in a narrow variation of δ18O between 1.2 and 1.6 per mil with δ18O fluid of 10.3 to 10.7 per mil. Fluid inclusion and oxygen isotope analyses suggest that a possible mechanism for magnetite deposition is boiling and dilution with surface (meteoric) fluids, which together with increasing pH and decreasing T explains iron ore formation.