Petrology
J. Ghalamghash; Sara Houshmand; Sayad Jamal Shaikhzakariaee; Hamideh Rashid
Abstract
The Kharsare intrusive mass (South of Ghorveh) is located in the middle part of the Sanandaj–Sirjan zone. The batholith comprises three plutonic units including gabbro- diorite, granite and syenite. In addition, the hybrid rocks with a lot of mixing and minling evidences (including lobate or/and ...
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The Kharsare intrusive mass (South of Ghorveh) is located in the middle part of the Sanandaj–Sirjan zone. The batholith comprises three plutonic units including gabbro- diorite, granite and syenite. In addition, the hybrid rocks with a lot of mixing and minling evidences (including lobate or/and ellipsoidal micro granular mafic enclaves sometimes with chilled margins in granite or in hybrid rocks; net-veining granite; and synplutonic brecciated mafic dikes) crop out in interaction zone between granites and gabbros. The calc-alkaline and metaluminous gabbro-diorite and High-K calc-alkaline and peraluminous granites emplaced in Late Jurassic, simultaneously. The peraluminous A-type syenite formed later and intrude two above mentioned plutonic rocks. Geochemical features suggest that gabbro-diorites and granites formed in an active continental margins. It seems the pioneer mafic magma formed in a subduction setting by partial melting of metasomatized mantle. It ascent and emplace in lower crust to produce the granitic melt. The mingling and mixing evidences that may support local crustal contamination of the mafic melt. The younger syenite is resulted from heating by intrusion of the mafic magma in the end phase of continental arc magmatism.
Economic Geology
Sahar Tarabi; Mohamad Hashem Emami; Sourosh Modaberi; Seyed Jamal Shaykh Zakariaee
Abstract
Momen-abad area, in the southeast of Birjand and the northeast of Sarbisheh, is located in the Sistan-Zemestan zone. Based on the field studies, petrography, geochemical (XRF) and X-ray diffraction (XRD) in two volcanic sequences, the alteration conditions in the area have been investigated. According ...
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Momen-abad area, in the southeast of Birjand and the northeast of Sarbisheh, is located in the Sistan-Zemestan zone. Based on the field studies, petrography, geochemical (XRF) and X-ray diffraction (XRD) in two volcanic sequences, the alteration conditions in the area have been investigated. According to mineralogy and chemical studies, bentonites are sodium-calcium and heterogeneous. Mineralogy findings indicate that smectite minerals, cristobalite and quartz, alkaline feldspars (albite and anorthite and sanidine), gypsum, calcite, hematite, holandite, klinoptiolite, kaolinite, ileite, and halite minerals form bentonites. In the first sequence, the effects of argillic and iron oxide alterations and in the second sequence, the effects of alteration of argillic, carbonate, chlorite, calcite, albite, silicification and iron oxide are found. Altered units which are related to the second sequence in four layers include Rhyolytic perlites of the vein, masses, lenses; white bentonites and green; Rhyodacite and dacite with the effects of alteration of devitrification, and the alteration of perlite to bentonite, advanced argillic and silicification. In addition, the composition textures of lava-pyroclastic, devitrification and the alteration of perlite to bentonite due to diagenetic alteration are found out. Glass argillization and feldspars in volcanic units, and the alteration of plagioclase to albite + sericit, biotite to chlorite, stone to quartz, calcite, zeolite and chlorite in perlites, iron oxide veins and red unit are found out in the sequences. Moreover, the change color of bentonite in the region related to alteration hydrothermal, and the presence of fluids and iron-magnesium-rich solutions are obvious in these sequences.
somaye kazemi koohbanani; seyed jamal sheikh zakariai; mohammad hashem emami; Rahim Dabiri
Abstract
KoheSiah volcanic complex is in north east of Qorveh in the Kurdistan province and in Sanandaj-Sirjan zone.The age of the studied region rocks are related to the quaternary time. Set volcanic cone with a crater that has been identified as unspecified and are an average height of 2157 meters above sea ...
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KoheSiah volcanic complex is in north east of Qorveh in the Kurdistan province and in Sanandaj-Sirjan zone.The age of the studied region rocks are related to the quaternary time. Set volcanic cone with a crater that has been identified as unspecified and are an average height of 2157 meters above sea level. The composition of volcanic rocks varies from basaltic composition, Basalitic andesites, andesite and , trachyandesite. On the basis of mineral chemistry the amphiboles are classified as calcic (magnesio-hornblende). Plagioclases vary from andesine-oligoclase to labradorite. Al-barometer accounts that the pressure of amphibole crystallization is 3.2 to 6.65 Kbar and Altotal versus Fetotal/(Mg+Fetotal) accounts the pressure between 4.5 to 7 Kbar. Hornblende - plagioclase thermometer shows 464 to 473 °C for equilibrium of these two minerals and biotite thermometer shows 500 to 650 °C for biotite in andesites. The estimated oxygen fugacity imply an oxidation magma (confirms iron oxide and enrichment of Mg in amphibole)
Petrology
mozhgan Taheri; afshin ashjaardalan; Mohammad hashem Emami; Seyed Jamal Shaikh Zakariay
Abstract
Abstract In the west and south-west part of Salafchegan near Zavarian village in Iran (In central Iranian volcano plotonic belt) there are some Plutonic rocks. Based on petrography and geochemistry findings these Plutonic rocks are Diorite, Monzonite and less Quartz monzonite. The main texture in Dioritic ...
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Abstract In the west and south-west part of Salafchegan near Zavarian village in Iran (In central Iranian volcano plotonic belt) there are some Plutonic rocks. Based on petrography and geochemistry findings these Plutonic rocks are Diorite, Monzonite and less Quartz monzonite. The main texture in Dioritic rocks is intergranular and in Monzonite is Porphyritic. Based on TAS diagram Samples located in Diorite, granodiorite and gabbrodiorite. Tectono-magmatic diagram Y Versus Zr shows the magmatic arc setting and Zr/TiO2 Versus Ce/P2O5 diagram contrasts postcolligenal magmatic arcs. Based on Chondrite and primitive mantle Spider diagrams, LREE have enriched to HREE in this area that makes the overal slope of these diagrams declined from left to right and this consident with the overal pattern of subduction zone. The results of petrography, geochemistry and tectonic setting studies in this area, indicate that neogene magmatism occurred in post colligenal tectonic setting - subduction of Neo-thetise ocean under central Iranian plate in neogen era.
Z. Nasr Esfahani; M. H. Emami; S. J. Sheikhzakariaee; S. H. Tabatabaei
Abstract
The study area is located in the Isfahan province and at the north of East Alloun Abad village. This area is a part of Urmia - Dokhtar belt in Central Iran. A large part of the area is formed from Eocene igneous rocks. These rocks include basaltic andesite and pyroclastic rocks of ignimbrite and ...
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The study area is located in the Isfahan province and at the north of East Alloun Abad village. This area is a part of Urmia - Dokhtar belt in Central Iran. A large part of the area is formed from Eocene igneous rocks. These rocks include basaltic andesite and pyroclastic rocks of ignimbrite and tuff. These rocks show porphyritic and microlithic texture with plagioclase, amphibole and clinopyroxene as the main mineral constituents. The secondary minerals such as chlorite, calcite, epidote and iron oxide are formed due to alterations. Electron microprobe analyses reveals that clinopyroxenes are diopside - augite. The study of clinopyroxene chemistry showed that the water was between 2 to 10% during clinopyroxene crystallization. The parental magma was calc-alkaline and tectonic setting is a subduction-related environment, based on clinopyroxene composition. Geothermobarometry of clinopyroxene gives temperature range of 925-1091°C and pressures range of 2-10 kbars for the formation of clinopyroxene in these rocks.
A. Ansari; S. J. Sheikh Zakariaee; S. Dargahi; M. Arvin
Abstract
The Chargonbad batholith is located close to Sirjan and southeast of Urumieh-Dokhtar magmatic zone . This batholith is acidic to intermediate in composition and intruded into the Eocene volcanic rocks. The main volume of these rocks consisted of granodiorite and monzogranite, but it also consists of ...
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The Chargonbad batholith is located close to Sirjan and southeast of Urumieh-Dokhtar magmatic zone . This batholith is acidic to intermediate in composition and intruded into the Eocene volcanic rocks. The main volume of these rocks consisted of granodiorite and monzogranite, but it also consists of quartzdiorite, tonalite and syenogranite. Their contacts are gradational. They have allotrimorphic granular texture with subordinate porphyritic texture. Their enclaves consist of xenoliths enclaves, microgranular mafic enclaves (diorite to quartzdiorite in composition) and autolith enclaves(tonalite, granodiorite and monzogranite in composition).The Chargonbad batholith rocks are also cut by different types of dykes which are mainly consisted of dykes and veins of pegmatitic stage, microgranular dykes (andesite and andesite basaltic in composition) and microgranular dykes that are similar to mafic enclaves. Evidenc show that the samples represent properties of I-type granitoids. Chargonbad granitoid has magnesium nature and shows cordellarian granites features. Based on the tectonomagmatic environment diagrams, all samples from the Chahargonbad plot in the island arc setting of a subduction zone and show active continental margin setting characteristics .
R Samadi; H Mirnejad; A.A Baharifar; S.J Sheikh Zakariaee
Abstract
The fibrolite garnet staurolite mica schist and staurolite garnet mica schist cropped out around the northwest of Khalaj, south of Mashhad in a SE_NW direction along the metamorphic complex of Kuh-e-Majuni. They have similar mineralogy and consist of quartz, annite, staurolite, almandine, muscovite, ...
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The fibrolite garnet staurolite mica schist and staurolite garnet mica schist cropped out around the northwest of Khalaj, south of Mashhad in a SE_NW direction along the metamorphic complex of Kuh-e-Majuni. They have similar mineralogy and consist of quartz, annite, staurolite, almandine, muscovite, zircon, and ilmenite; however, fibrolite in fibrolite garnet staurolite mica schist, and chlorite and tourmaline in the staurolite garnet mica schist are additionally found. Application of garnet - biotite thermometry and GBMAQ barometry indicates the temperatures and pressures of 560 and 605 °C / 3.5 and 5 kilobar for fibrolite garnet staurolite mica schist and temperatures of 489 and 547 °C (in 3.5 to 5 kilobar) for the staurolite garnet mica schist. Pressure and temperature increasing during the garnet growth indicates the effect of regional and contact thermal metamorphism on these rocks. Based on mineral paragenesis in KFMASH system, the metamorphic degree of regional metamorphism was about lower amphibolite (in staurolite garnet mica schist) to middle amphibolite facies (in fibrolite garnet staurolite mica schist). Meanwhile, intrusion of the Khalaj granitoid and its thermal diffusion raised the metamorphic temperature up to lower amphibolite facies (in staurolite garnet mica schist) and middle amphibolite facies (in fibrolite garnet staurolite mica schist), and consequently, this caused the fibrolite formation in the sample close to the pluton (i.e. fibrolite garnet staurolite mica schist).
R. Samadi; M. V. Valizadeh; H. Mirnejad; A. A. Baharifar; S. J. Sheikh Zakariaee
A. Ghanbari; S. S. Zerangzadeh; F. Rezaee; S. J. Zakariaee
Abstract
In this study, the geologic formations of central part of Karaj alluvium are studied and a new division for layers is presented. The results of hundreds geotechnical in-situ and laboratory tests in Karaj alluvium were carried out and analyzed. Based on soil material properties, the study area is divided ...
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In this study, the geologic formations of central part of Karaj alluvium are studied and a new division for layers is presented. The results of hundreds geotechnical in-situ and laboratory tests in Karaj alluvium were carried out and analyzed. Based on soil material properties, the study area is divided to six individual layers. In each layer, the results of a large number of in situ and laboratory test to determine geotechnical properties of soil are classified and analyzed. Finally, average geotechnical parameters for different layers of soil in study area are presented. To determine the range of modulus of elasticity and relation between bearing capacity and SPT number in Karaj alluvium, results of laboratory and in-situ tests were assessed and compared with instrumentation data.
