OLCA

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1 - مقایسه مواد آذرآوری (پومیس و لاهار) دره های ملار و رینه در مخروط آتشفشانی دماوند
امیرهوشنگ شیرازی منوچهر فرج زاده

در این مقاله به مقایسه مواد آذرآوری در دره های ملارورینه در حوضه آبخیز یخار در دامنه جنوب شرقی مخروط آتشفشان دماوند پرداخته می شود.نقش مطالعه مواد آذرآوری در شناخت بیشتر مخروط آتشفشانی دماوند و قدرت انفجاری آن و خسارت احتمالی به مناطق مسکونی پیرامون، نکته قابل توجهی است چکیده کامل

در این مقاله به مقایسه مواد آذرآوری در دره های ملارورینه در حوضه آبخیز یخار در دامنه جنوب شرقی مخروط آتشفشان دماوند پرداخته می شود.نقش مطالعه مواد آذرآوری در شناخت بیشتر مخروط آتشفشانی دماوند و قدرت انفجاری آن و خسارت احتمالی به مناطق مسکونی پیرامون، نکته قابل توجهی است که اهمیت این تحقیق را نشان می دهد. جوانترین فوران شناخته شده دماوند، جریان گدازه ها در دامنه غربی با سنی حدود 7.3 هزار سال و قدیمی ترین آن با سنی حدود 1.5 میلیون سال مربوط به بخش شمالی منطقه می باشد. سه بخش از رسوبات پومیس جوان در دامنه جنوبی غربی تا جنوب شرقی با عناوین کرم پشته، رینه و ملار با محدوده سنی 7.3 تا 25 هزار سال قابل شناسائی می باشند که پومیس رینه و ملار موضوع مورد مطالعه این تحقیق می باشد. پومیس های بارشی ملار و رینه به سمت شرق پراکنده شده و رسوبات پومیس جریانی آذر آواری به فاصله 20 کیلومتری از قله گسترش پیدا کرده و در آخرین مرحله توسط لاهار پوشیده شده است. این تحقیق با استفاده از روش توصیفی تحلیلی و با بهره گیری از ابزار های مناسب به همراه بازدید میدانی به انجام رسیده است. هدف از این تحقیق شناخت مواد آذرآواری جوان و محدوده پراکندگی و تفاوتهای موجود بین آنها وشناخت قدرت انفجاری دماوند با توجه به پراکندگی مواد آذرآواری می باشد. نتایج مطالعه نشان میدهد، دماوند فوران های انفجاری با قدرت بالا داشته که سبب پراکندگی مواد آذرآواری از جمله پومیس در محدوده وسیع شده وبین پومیس مناطق مختلف از جمله ملار و رینه تفاوت هایی در زمینه جورشدگی، گردشدگی، نوع تشکیل (بارشی و جریانی) دیده می شود. رسوبات آذرآواری توسط لاهار پوشیده شده و میزان و گستردگی لاهار در تمام قسمت ها یکسان نبوده بطوریکه در منطقه مورد مطالعه لاهار رینه بدلیل کاهش شیب از ضخامت و گستردگی بیشتری نسبت به ملار برخوردار می باشد. پرونده مقاله

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2 - Development of Geotourism in the southeast caspian seaboard with special view on mud volcanoes
Parvaneh Rezaei Rouzbahani

The development of geo-tourism in the southeast of the Caspian seaboard with a special view on the therapeutic potential of mud volcanoes by geochemical and mineralogical methods for the first time was studied (Case study: Naftlicheh mud volcano). The results of mineral چکیده کامل

The development of geo-tourism in the southeast of the Caspian seaboard with a special view on the therapeutic potential of mud volcanoes by geochemical and mineralogical methods for the first time was studied (Case study: Naftlicheh mud volcano). The results of mineralogical and geochemical studies carried out by XRF&XRD methods show that Naftlicheh mud volcano has no significant toxic substances and its main minerals are quartz, calcite, dolomite, halite, clay minerals such as smectite and illite. There is a high amount of elements such as boron, copper, iodine, bromine, vanadium, magnesium, sodium, calcium, organic acids, aromatic hydrocarbons, and bicarbonate. So Naftlicheh mud volcano has a therapeutic aspect and can be one of the essential destinations for curative geo-tourism. In addition to therapeutic effects, mud volcano contains essential scientific information about evaluating gas and oil reservoirs, salt domes and the tectonic situation of the region (faults and subduction) therefore as an educational geo-site can attract a large number of domestic and foreign tourists and geo-tourists. Also, in line with geo-tourism development of the Naftlicheh volcanic mud area, some guidelines are suggested, such as: Presenting media publicity nationally and internationally about the therapeutic potential of Naftlicheh mud volcano. پرونده مقاله

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3 - Pliocene volcanic activity of the Harrat Ash-Sham, South of Syria: geochemistry and petrogenesis
Safwan Dawod Ali Al-Mishwat Abdulkarim Al Abdalla

The Cenozoic volcanic activity of the Harrat Ash Sham volcanic field in south of Syria is a part of the extensive magmatism that took place in the auxiliary extension faults along the Dead Sea Fault Zone from upper Eocene to Holocene. Pliocene volcanic rocks form an imp چکیده کامل

The Cenozoic volcanic activity of the Harrat Ash Sham volcanic field in south of Syria is a part of the extensive magmatism that took place in the auxiliary extension faults along the Dead Sea Fault Zone from upper Eocene to Holocene. Pliocene volcanic rocks form an important part of igneous succession in Syrian Part of Harrat as Sham. These rocks vary from basalts flows to scoria. Pliocene basalts are divided into three primary petrographic groups: olivine basalt, olivine-pyroxene basalt and basanite. The three petro-types are alkaline and have similar compositional ranges of major and trace elements. Variations in the contents of major and minor elements in the Pliocene basaltic rocks are very slight. Such homogeneity in the chemical composition indicates to the operation of petrological processes that reinforced each other during the genesis of these rocks. The geochemical characteristics of the Pliocene basalt rocks reflect crystallization from primitive basic magmas that have experienced limited crystal fractionation process subsequent to their derivation by partial melting of the upper mantle. پرونده مقاله

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4 - Eocene-Oligocene volcanic units of momen abad, east of Iran: petrogenesis and magmatic evolution
Sahar Tarabi Mohamad Hashem Emami Sourosh Modabberi Seyed Jamal Sheikh Zakariaee

10.30495/ijes.2019.665319

This study investigates petrology and major, minor, and rare earth elements &lrm;geochemistry of &lrm;East Iranian Eocene–Oligocene volcanic rocks in Sistan suture &lrm;zone, to examine their &lrm;petrogenesis and magma evolution. The volcanic rocks include andesi چکیده کامل

This study investigates petrology and major, minor, and rare earth elements &lrm;geochemistry of &lrm;East Iranian Eocene–Oligocene volcanic rocks in Sistan suture &lrm;zone, to examine their &lrm;petrogenesis and magma evolution. The volcanic rocks include andesite, trachy-andesite, dacite &lrm;and rhyolite. &lrm;These calc-alkaline rocks of high-K series are enriched in Large &lrm;Ion Lithophile &lrm;Elements of Rb and Ba and depleted in High Field Strength Elements &lrm;(e.g. Ti and Nb). The REE &lrm;pattern shows Eu negative anomaly. These &lrm;features are comparable with rocks in subduction &lrm;zone of continental &lrm;margin setting. &lrm;The petrographic features and the geochemical variation &lrm;of major oxides and trace &lrm;elements against SiO2 can be related to fractional &lrm;crystallization in parent magma. The trace &lrm;element ratios, e.g. Nb/La, Nb/U, Ba/Rb, Nb/Y and Rb/Y, verify crustal &lrm;contamination with a remarkable upper &lrm;crustal contamination as the main &lrm;process in the &lrm;formation of volcanic series. &lrm;The ratios of Nb/Ba and Nb/Zr indicate that magmatic activity in Momen Abad had &lrm;resulted &lrm;from sub-continental lithospheric mantle. In addition, Nb/Y and Zr/Yb versus &lrm;Ta/Yb reveals an &lrm;E-MORB like mantle source. A spinel lherzolite composition &lrm;with significant role of the &lrm;AFC processes are deduced from the concentrations of Yb and &lrm;Y, and the ratios of Th/Yb and &lrm;La/Yb. &lrm;The Ba/Nb, Ba/Th and Th/Nb ratios presume a metasomatized mantle source &lrm;resulted from &lrm;the melting of upper crust sediments inherited from the subduction of &lrm;Neotethys ocean beneath &lrm;the Lut Block. &lrm; پرونده مقاله

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5 - Distribution and geochemical variations among paleogene volcanic rocks from the north-central Lut block, eastern Iran
Saeed Saadat Charles Stern

The Lut block in eastern Iran is a micro-continental block within the convergent orogen between the Arabian, Eurasian and Indian plates. Large areas of the north-central, eastern, and western Lut block are covered by volcanic rocks of Paleogene, Neogene and Quaternary a چکیده کامل

The Lut block in eastern Iran is a micro-continental block within the convergent orogen between the Arabian, Eurasian and Indian plates. Large areas of the north-central, eastern, and western Lut block are covered by volcanic rocks of Paleogene, Neogene and Quaternary age. Peak volcanic activity took place in the north-central part of the Lut block during the Eocene, and then dramatically decreased, becoming more restricted to the eastern and western margins of the block during the late Miocene and Quaternary. There is also significant variation in chemistry between the Paleogene igneous rocks from the north-central part compared to the Neogene and Quaternary volcanic rocks from the western and eastern margins of the Lut block. The Neogene and Quaternary olivine basalts, which were erupted along both margins of the Lut block, are similar in trace element chemistry to the average composition of oceanic island basalt. In contrast, the Paleogene volcanic units of the north-central Lut block, which include basalts through rhyolites, follow both calc-alkaline and alkaline trends. Low TiO2 and high Ba/Nb and La/Nb ratios for both Paleogene basalts and andesitic samples from the north-central Lut block suggest affinities, at least for some of these samples, with convergent plate boundary arc magmas. LILE/HFSE ratios, interpreted as an indication of subduction signature, increase to the south-southwest of the central Lut block, where Neotethys oceanic crust was subducted beneath Iran in a northeastern direction from approximately Late Triassic to Late Oligocene time. We suggest that components derived from low angle subduction of this crust during the Mesozoic and early Tertiary were stored in the mantle lithosphere below the north-central Lut block until the Paleogene, when changing subduction geometry, associated with the collision of Arabia with Iran and the closing of Neotethys, caused hot asthenosphere to well up under the Lut block. This created the Eocene peak in volcanic activity, generating basalts from asthenospheric mixed with lithospheric melts, with both alkaline and calc-alkaline affinities. After this volcanism waned, becoming restricted during the Neogene to OIB-type alkaline basalts erupted through deep lithospheric structures along both the western and eastern margins of the Lut block. پرونده مقاله

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6 - Magmatic interactions as recorded in plagioclase phenocrysts of quaternary volcanics in SE Bam (SE Iran)
Abdollah Yazdi Afshin Ashja Ardalan Mohammad Hashem Emami Rahim Dabiri Mohammad Foudazi

10.30495/ijes.2019.667379

In the southeast of Iran (SE Bam), there is a collection of volcanic rocks with andesite, basalt and trachyandesite composition. The textures of these rocks are often porphyritic with microlithic, porphyric cavity, and sometimes glomeroporphyritic, sore throat trachytic چکیده کامل

In the southeast of Iran (SE Bam), there is a collection of volcanic rocks with andesite, basalt and trachyandesite composition. The textures of these rocks are often porphyritic with microlithic, porphyric cavity, and sometimes glomeroporphyritic, sore throat trachytic. Main minerals include olivine, clinopyroxene, plagioclase and secondary minerals including opaque minerals, Iddingsite, secondary biotite, chlorite and calcite. The analysis of magma textures gives us valuable information about magmatic processes. Micro textures in plagioclase of volcanic rocks in the region are divided into two groups: a) texture-linked to crystalline growth including: sieve texture, oscillatory zoning and degraded surfaces and b) Morphological textures such as glomerular crystals. Sieve texture and zoning in crystal represent processes such as magmatic mixing and abrupt reduction of pressure and, in general, unbalanced conditions in magmatic reservoirs. Based on electron microscope studies, plagioclase of igneous rocks of the region is within the boundaries of labradorite and bytownite.In the southeast of bam, there is a collection of volcanic rocks with andesite, basalt and trachy andesite composition. The texture of these rocks are often porphyritic with microlithic, porphyric cavity, and sometimes glomerulophorphuri, sore throat trachytic. Main minerals include Olivine, Clinopyroxene, Plagioclase and secondary minerals including opaque minerals, Iodenzyte, secondary Biotite, Chlorite and Calcite. Sieve texture and zoning in crystal represent processes such as magmatic mixing and abrupt reduction of pressure and, in general, unbalanced conditions in magmatic reservoirs. پرونده مقاله

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7 - Study of micro-textures and chemistry of feldspar minerals of East Sarbisheh volcanic complex (Eastern Iran), for evidence of magma chamber process
Mahboobeh Jamshidibadr Sahar Tarabi Kazem Qolizadeh

10.30495/ijes.2020.671654

The Eocene-Oligocene Sarbisheh volcanic complex is a part of the Lut-Sistan Zone that outcrops in eastern Iran. In the east of this complex, three groups of volcanic rocks (i.e., andesite, dacite, and rhyolite) exist. Plagioclase as the main mineral of these rocks is fo چکیده کامل

The Eocene-Oligocene Sarbisheh volcanic complex is a part of the Lut-Sistan Zone that outcrops in eastern Iran. In the east of this complex, three groups of volcanic rocks (i.e., andesite, dacite, and rhyolite) exist. Plagioclase as the main mineral of these rocks is found with varying micro-textures. Based on a changing trend in the concentration of anorthite, the developed micro-textures (coarse/fine-sieve, fine-scale oscillatory zoning, and resorption surfaces) are not affected by the chemical composition of the magma. Rather, such changes can occur by temperature variations during magma crystallization or H2O fugacity changes in the magmatic system. The recharge of basic magma leads to a temperature rise, partial melting of the central part of the crystal, and formation of sieve texture, and resorption surfaces. Consequently, the chemical changes of magma in the chamber cause the formation of An-enrichment in the outer layer of the plagioclase crystal and formation of oscillatory zoning. In addition, the morphological micro-textures (i.e., glomerocryst, synneusis, swallow-tailed, microlite, and broken crystals) are developed by the influence of dynamic behavior of the crystallizing magma and magmatic differentiation. The thermobarometry evaluation using pyroxene and biotite chemistry showed that the temperature ranges between 700 and 1150°C and the pressure were less than 2 kbar. پرونده مقاله

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8 - Petrology and tectono-magmatic environment of the volcanic rocks of West Torud – Iran
Abdollah Yazdi Elham Shahhosseini Farhad Moharami

10.30495/ijes.2022.1929200.1601

Middle-Upper Eocene volcanic and volcano-sedimentary rocks of the Torud region have been formed by the sequences of basic-intermediate lavas, pyroclastic rocks, and sedimentary layers (e.g., siltstone, sandstone, and nummulite-bearing limestone) within a shallow marine چکیده کامل

Middle-Upper Eocene volcanic and volcano-sedimentary rocks of the Torud region have been formed by the sequences of basic-intermediate lavas, pyroclastic rocks, and sedimentary layers (e.g., siltstone, sandstone, and nummulite-bearing limestone) within a shallow marine basin. According to microscopic studies, the volcanic rocks of the region include basalt, basaltic andesite, trachyandesite, andesite, and dacite. These rocks have originated from the differential crystallization processes and occasionally calc-alkaline contamination geochemical properties. Generally, they contain olivine, clinopyroxene, and plagioclase ± amphibole minerals. Porphyritic to megaporphyritic textures with microlithic and flow matrixes are observed in these rocks. Studying the main and rare elements of these rocks indicates that reducing MgO content is accompanied by an increase in Al2O3, K2O, Na2O, and SiO2 and a decrease in Fe2O3 and CaO concentrations. These rocks are mainly enriched in LIL and LREE elements but depleted of HFS elements. The prominent features of these rocks are the presence of positive anomalies in the K, Sr, Rb, and Ba elements, the depletion of some samples of Nb and Ta, and their depletion of Ti and P. This result reveals the crustal contamination of the mantle mafic magma constructing these rocks. According to the geochemical data, magmatic pollution has not been an effective process in the formation of these rocks. In addition, the relatively higher levels of Cr, Ni, and MgO in the alkali basalts of the region indicate that these rocks are originated from partial melting (5 to 10%) of a spinel-garnet peridotite. Overall, they have no subduction-dependent rock characteristics and mainly represent characteristics of alkali basaltic magmas of the preliminary back-arc basin (BAB). These features, attributed to their calc-alkaline nature, represent the formation of these rocks in a tectonic back-arc setting in the Middle-Upper Eocene. پرونده مقاله

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9 - Geochemistry and tectonomagmatic environment of Eocene volcanic rocks in the Southeastern region of Abhar, NW Iran
Masoud Nazari Mohammad Ali Arian Ali Solgi Reza Zareisahamieh Abdollah Yazdi

10.30495/ijes.2023.1956689.1746

Eocene volcanic are exposed in southeast of Zanjan in the Tarom magmatic zone that located in the Central Iran structural zone. The Abhar Eosen pyroclastic with andesite, trachy-andesite, dacite and rhyolite along with tuff compositions is located 120 km southeast of Za چکیده کامل

Eocene volcanic are exposed in southeast of Zanjan in the Tarom magmatic zone that located in the Central Iran structural zone. The Abhar Eosen pyroclastic with andesite, trachy-andesite, dacite and rhyolite along with tuff compositions is located 120 km southeast of Zanjan. Mineralogically point of view, the studied volcanic rocks have low quartz, negligible alkaline feldspar, abundant plagioclase, and pyroxene contents. Textureally, Porphyritic, microlithic porphyritic, glomeroporphyritic, and poikilitic are predominant in these rocks. All of the studied samples display REE patterns characterized by LREE-enriched (Rb and Ba) and HREE-depleted segments typical of arc lavas which is one of the characteristics of subduction zone. The geochemical characteristics of the studied samples indicated that fractional crystallization is the primary cause of the diversity and differentiation of these rocks compared to crustal contamination. The rocks of the study area are composed of a similar origin to the OIB (mantle components) and partial melting of subcontinental lithospheric mantles. Of course, this mantle source has been modified by recycled sediments and melt released from the edge of the subducting oceanic crust. پرونده مقاله

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10 - A study of different zoning types in clinopyroxenes of sodic and potassic alkaline volcanic rocks from North Lahrud, NW Iran
Gholamreza Ahmadzadeh Reza Zamani

Clinopyroxene phenocrysts and microphenocrysts in potassic and sodic Eosen alkaline volcanic rocks from the northern Lahrud (NW Iran) record various stages in the crystallization and evolution history of the alkaline melt as well as its origin. The rock series hosting t چکیده کامل

Clinopyroxene phenocrysts and microphenocrysts in potassic and sodic Eosen alkaline volcanic rocks from the northern Lahrud (NW Iran) record various stages in the crystallization and evolution history of the alkaline melt as well as its origin. The rock series hosting the clinopyroxene phenocrysts is phonolitic tephrite and tephritic phonolite composition. Theses rocks generally show porphyritic texture and have a variable phenocryst-rich nature (25–50%), with phenocryst assemblages characterized by Cpx ± An ± Pl. The studied clinopyroxenes have relatively high Mg-numbers (0.66-0.90), variable Al2O3 (3.77-7.31 wt%), low TiO2 (<2.02 wt%) and Na2O (<1.23 wt%) contents and low AlVI/AlIV ratios (mostly <0.25), suggesting relatively low-pressure crystallizing conditions of the magma in the magma chamber. The calculated pressures for the clinopyroxenes in these rocks vary in the range of 4–5.5 kbars. Oscillatory reverse zoning of clinopyroxenes related to the different crystallization paths under a variable oxygen fugacity and different oxidation conditions and sudden pressure differentiation and magma mixing processes. Normal zoning related to the differentiation and fractional crystallization of the magma. The resorption texture of core parts of some clinopyroxenes are attributed to the changes of crystallization pressure though such textures have been ascribed to magma mixing. پرونده مقاله

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11 - Petrological and geodynamical constraints of Chaldoran basaltic rocks, NW of Iran: evidence from geochemical characteristics
Farhad Moharami Issa Azadi Mirsaleh Mirmohamadi Javad Mehdipour Ghazi Mohammad Rahgoshay

Chaldoran area in NW of Iran has Mesozoic oceanic crust basement. The studied rocks of this region can be divided into three groups: ophiolitic gabbros and pillow lavas, ophiolitic volcanoclastics and Eocene lava flows. Ophiolitic mafic rocks show continental volcanic a چکیده کامل

Chaldoran area in NW of Iran has Mesozoic oceanic crust basement. The studied rocks of this region can be divided into three groups: ophiolitic gabbros and pillow lavas, ophiolitic volcanoclastics and Eocene lava flows. Ophiolitic mafic rocks show continental volcanic arc natures and Eocene lava flow shows OIB-like nature. During the Mesozoic,the Chaldoran region was situated in the active continental margin of the Iranian plate due to Neotetyhan subduction beneath the SSZ (Sanandaj-Sirjan Zone). As the Neo-Tethyan subduction regime changed, a rift in the Chaldoranareagenerated, which caused a continental back arc basin during the Upper Cretaceous. Along with spreading basin in the oceanic ridge, in the surface of new formed oceanic crust, some oceanic island were active and formed volcanoclastic rocks in the Chaldoran Oceanic crust. They were result of ascending continental arc nature plumes that formed in the sub-oceanic crust and up on Neo-Tethys subducted slab in the mantle wedge. After of finishing of spreading this basin in early time of Paleocene, sedimentation followed up to the Middle Eocene. In the Upper Eocene, alkaline and OIB-like volcanism was active in the Chaldoranareadue to breaking off the Neo-Tethyan subducted slab in the sub-oceanic crust of Chaldoran area and developed an asthenosphric window. پرونده مقاله

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12 - Gatan Mud Volcanoes, Oman Sea Coast in Southwestern Hormozgan, Iran
Mohammadsadegh Dehghanian Zahra Abedpour Seyed Mohammad Mirhosseini

Iran's mud volcanoes are clearly visible on the coastal plains of the Oman and Caspian Seas. There are 30 Gatan Mud Volcanoes located in the southeast of Iran: 15 of which are located between Jask and Minab in Hormozgan province, nine are between Chabahar and Jask Ports چکیده کامل

Iran's mud volcanoes are clearly visible on the coastal plains of the Oman and Caspian Seas. There are 30 Gatan Mud Volcanoes located in the southeast of Iran: 15 of which are located between Jask and Minab in Hormozgan province, nine are between Chabahar and Jask Ports, and another six are between Chabahar and the Iran-Pakistan border in Sistan and Balouchestan Province. After some studies and investigations, research was performed on some of the mud volcanoes in the western Jask city located in the west of lower Gatan village. Gatan is located in the eastern coast of Hormozgan Province between the counties of Jask and Minab and on the coastal region of Makran. Being located on the entrance of the Strait of Hormuz and due to marine currents, it has certain sedimentology circumstances. Formation of Gatan Mud Volcanoes is a result of rising muddy water along the faults and cracks in the crust to the earth's surface. Results of mineralogical studies indicate that clay and limestone samples contain fossils and abundant minerals include quartz, albite, illite, calcite and dolomite. پرونده مقاله

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13 - Petrogenesis of volcanic rocks from Razei region in Northwest Ardabil, Iran
Yousef Vasigh

The Razei region in the northwest of Ardabil is considered a part of West Alborz-Azerbaijan. Rocks in this area were created by Eocene volcanic activities. These rocks range from andesite to olivine basalt. The common texture of these rocks is Porphyritic with microlith چکیده کامل

The Razei region in the northwest of Ardabil is considered a part of West Alborz-Azerbaijan. Rocks in this area were created by Eocene volcanic activities. These rocks range from andesite to olivine basalt. The common texture of these rocks is Porphyritic with microlithic matrix. The phenocrysts of these rocks are often clinopyroxene, plagioclase, and olivine. The texture is made of microlithic plagioclase and fine crystals of pyroxene. The studied rocks have clear desire to alkali basalts in terms of chemical nomenclature. Disequilibrium factors between liquid and crystal show the processes of magmatic evolution in an open thermodynamic system. The mixed climate in this region has probably contributed the most to changing the chemical composition of these rocks. In the spider diagrams, enrichments often include some LIL elements and depletions usually include some HFS elements. Enrichment of LILE is probably accompanied with the contamination of the basic magma with materials from continental lithosphere. The volcanic rocks in Razei have mainly geochemical characteristics of back arc basin, and the magmas that created the rocks in this region have an origin of lithospheric mantle. پرونده مقاله

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14 - Using Wind Data to Predict the Risk of Volcanic Eruption: An Example from Damavand Volcano, Iran
M. Mortazavi R.S.J. Sparks

Damavand volcano is located 60 km to the East North- East of Tehran. It is a dormant stratovolcano outcrop in the Alborz Mountains of northern Iran and is the highest mountain (5670 m) in the Middle East and West Asia. Mazandaran Province, one of the most populous provi چکیده کامل

Damavand volcano is located 60 km to the East North- East of Tehran. It is a dormant stratovolcano outcrop in the Alborz Mountains of northern Iran and is the highest mountain (5670 m) in the Middle East and West Asia. Mazandaran Province, one of the most populous provinces by population density, Semnan and Gorgan provinces further east are neighbours of the Damavand. Volcanism in Damavand goes back to at least 1 Ma year ago and the latest eruption occurred 7000 years ago. Tephra dispersal in volcanoes strongly depends on atmospheric information in particular wind direction and velocity in stratospheric and tropospheric levels. We present an analysis of wind data to assess the hazards that would result from tephra fall in the cities and provinces neighbouring Damavand. Atmospheric data were provided from the Meteorological stations at Mehr-Abaad airport, Wyoming University and global data sets. We examine wind data from 17 standard pressure levels which cover from 5700 meter (Damavand peak) to 31 km above sea level. If Damavand moved into a state of unrest then a major explosive eruption is a plausible scenario that should be planned for. The results confirm that the area to the south and east of volcano will be affected by tephra. Communities around the southern and eastern flanks of the volcano also have high hazard. Wind data also shows the effects of season on dispersal of tephra from a 25 km high eruption column. Tephra dispersal is dominantly towards the east in all seasons for eruption columns up to 20 km above sea level. Mazandran, Semnan and Gorgan providence could be affected in this case. At 25 km- high eruption column and during the summer there are easterly winds; therefore, the tephra would disperse toward the east. In this case Tehran could experience a tephra fall deposit پرونده مقاله

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15 - Petrogenetic Evolution of Plio-Quaternary Mafic Lavas in Nehbandan (East Iran)
Mohammad Reza Ghasempour Javad Mehdipour Ghazi Habib Biabangard Rahim Dabiri

Both the Sistan Suture Zone of eastern Iran and the Nehbandan Fault contain Plio-Quaternary Nehbandan mafic lavas. Positive anomalies in the large ion lithophile elements (LILE) and negative anomalies in Nb (niobium) exist in these mafic lavas. This indicates the occurr چکیده کامل

Both the Sistan Suture Zone of eastern Iran and the Nehbandan Fault contain Plio-Quaternary Nehbandan mafic lavas. Positive anomalies in the large ion lithophile elements (LILE) and negative anomalies in Nb (niobium) exist in these mafic lavas. This indicates the occurrence of subduction magmatism and post-collision volcanism. Petrologic and geochemical analyses distinguished two groups of lava. Group I contains alkaline basalts with a slight depletion in Nb while Group II contains sub-alkaline basaltic andesite to andesite with a sharp depletion in Nb. Geochemical studies show that fractional crystallization and crustal contamination played an important part in the evolution of the Nehbandan lavas. Group II, however, was more greatly affected than Group I. Geochemical studies also indicate that these lavas may have been generated due to a low degree of partial melting (<5%) of garnet and the spinel-bearing lithospheric mantle; Group I shows more garnet than spinel while Group II shows the opposite. The research carried out for this paper suggests that the Plio-Quaternary Nehbandan mafic lavas were formed as a result of slab detachment or delamination and domination, an extensional condition correlated to the thinning of the crust and lithosphere in the Sistan Collision Zone. These conditions are concomitant with localized stretching along the Nehbandan Fault and the upwelling of magma forming mafic lavas. پرونده مقاله

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16 - Determination of the Geological Conditions During the Formation of Kaolinite and Bentonite Deposits in NW Alborz Mountains (Pirkoh-Deylaman) of Iran and the Study of Its Practical Properties for Use in the Porcelain Industry
Farzad Asadi Ali Darvishzadeh Ali Montezeri

The area under study is located in northern Iran at 36° 47’ latitude and 50° 12' longitude. It is 15 km from southeastern Deylaman. Petrological study of the kaolin mother rock (Eocene age) under a microscope shows that the rock is vitric tuff with a rhyol چکیده کامل

The area under study is located in northern Iran at 36° 47’ latitude and 50° 12' longitude. It is 15 km from southeastern Deylaman. Petrological study of the kaolin mother rock (Eocene age) under a microscope shows that the rock is vitric tuff with a rhyolitic combination containing falcated and embowed glass shards. The thickness of the layer is approximately 20 meters, formed unconformably on a layer of conglomerate with a thickness of approximately 400 meters. Because the shards have a falcated and embowed shape and the percentage of reworked material within them is low, the tuff can be considered a type of pyroclastic airfall. The results of the study prove that ash falling occurred in the water. The stratabound layers show syngenetic deposits to be the main factor in the formation of the clay, bound as a result of alterations. پرونده مقاله

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17 - تحلیل بن‌مایۀ اسطوره‌ای کوه آتشفشان در چهار منظومۀ غنایی همای و همایون، گل و نوروز، جمشید و خورشید و مهر و ماه
سمانه عباسی حسن طباطبایی عصمت اسماعیلی

بن‌مایه‌های اسطوره‌ای نامیرا و ماندگار، با ویژگی انعطاف‌پذیری خود و با معانی گسترده، عمیق و شگرفی که در خود دارند، به مقتضای خصوصیات فکری و اجتماعی ادوار مختلف و همچنین متناسب با مضمون روایات گوناگون همواره در این روایات حضور می‌یابند و به جریان‌یافتن باورهایی که پایه و چکیده کامل

بن‌مایه‌های اسطوره‌ای نامیرا و ماندگار، با ویژگی انعطاف‌پذیری خود و با معانی گسترده، عمیق و شگرفی که در خود دارند، به مقتضای خصوصیات فکری و اجتماعی ادوار مختلف و همچنین متناسب با مضمون روایات گوناگون همواره در این روایات حضور می‌یابند و به جریان‌یافتن باورهایی که پایه و اساس شکل‌گیری آنها محسوب می‌شوند، تداوم می‌بخشند. یکی از این بن‌مایه‌های ماندگار کوه آتشفشان است که چون اژدها یا اهریمنی جلوه می‌کند و مبارزۀ شخصیت اصلی روایت با آن در راستای اثبات شجاعت و لیاقت او برای رسیدن به مقصود و همچنین برکت‌بخشی برای دیگران تعبیر می‌شود. این بن‌مایۀ کهن، که قدمتش به اساطیر آریایی می‌رسد، فقط در روایات حماسی حضور نیافته است، بلکه نمونه‌های جابه‌جاشدۀ آن را می‌توان در برخی از منظومه‌های غنایی نیز مشاهده کرد. در این مقاله، به روش توصیفی-تحلیلی به بررسی بن‌مایۀ اسطوره‌ای کوه آتشفشان در چهار منظومۀ غنایی همای و همایون، گل و نوروز، جمشید و خورشید و مهر و ماه و همچنین شباهت و تفاوت آن با روایات حماسی پرداخته می‌شود و جریان پویای اساطیر در متونی غیر از حماسه‌ها اثبات می‌گردد. پرونده مقاله

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18 - کانی شناسی و ژئوشیمی کانسنگ و سنگ میزبان کانسار منگنز جلال(جنوب غربی قم)
منصور مهدوی محمد یزدی محمد هاشم امامی

معدن منگنز جلال در شمال غرب معدن و نارچ،در جنوب غربی قم و در کمربند ولکانیکی ارومیه-دختر قرار گرفته است.بخش عمده رخنمون های منطقه را سنگهای آذرین -رسوبی تشکیل می دهند.توف،توف شیلی و سیلتی،گدازه های آندزیت بازالتی اسپیلیتی شده و گدازه های اسپیلیتی که با ساختمان بالشی سنگ چکیده کامل

معدن منگنز جلال در شمال غرب معدن و نارچ،در جنوب غربی قم و در کمربند ولکانیکی ارومیه-دختر قرار گرفته است.بخش عمده رخنمون های منطقه را سنگهای آذرین -رسوبی تشکیل می دهند.توف،توف شیلی و سیلتی،گدازه های آندزیت بازالتی اسپیلیتی شده و گدازه های اسپیلیتی که با ساختمان بالشی سنگهای غالب منططقه می باشند.یک سری توده های آذرین درونی در منطقه رخنمون دارند که جوان تر از توالی آذرین- رسوبی بوده و در آنها نفوذ کرده است.بعلاوه دایک های متعددی با ترکیب آندزیت بازالتی،مخصوصا در بخش شمال غرب منطقه مشاهده می شوند که تمام واحدهای سنگی را قطع نموده و جوان تر از همه بخشهای آن ها می باشند.این کانسار درون سنگهای آتش فشانی بالایی قرار دارد.کمر پایین و کمربالایی لایه منگنز دار را گدازه های آندزیت بازالتی و گدازه های اسپیلیتی تشکیل می دهند.لایه معدنی به موازات یکدیگر و در یک روند شمال غربی-جنوب شرقی دارند.گسترش طولی این لایه ها در حدود 200 متر می باشد.لایه های منگنز دار این معدن در طول توسط چندین گسل (با امتداد تقریبا عمود بر امتداد لایه ها) قطع و جابجا شده است که در منتهی علیع شمال غرب این معدن به یک گسل نسبتا بزرگ محدود میگردد.موازی بودن لایه ها و همچنین عملکرد گسلها سبب تفکیک این لایه ها شده است.به منظور تسهیل کار استخراجی آنها به نامهای معدن جلال D,B,A نامگذاری شده اند.بررسی پروفیل گمانه ها نشان می دهد که شیب لایه ها در اعماق به سمت شمال شرق می باشد.این کانسار یک کانسار پرشیب است که برخی از گسلهای موجود باعث برگشتگی آنها شده اند.کانه های اصلی در این لایه ها شامل پیرولوسیت،پسیلوملان،اکسیدهای منگنز و کانی های باطله همراه اغلب کواتز و کلیست است.مطالعات صحرایی،کانی شناسی و ژئوشیمیایی نشان میدهد که این کانسار از نوع اپی ترمال است. پرونده مقاله

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19 - مطالعه ژئو شیمی ،محیط زمین ساختی و سنگ نگاری توده گرانیتوئیدی آستانه اراک(جنوب باختری اراک)
عباس عسگری

توده گرانیتوئیدی مزبور در 45 کیلومتری جنوب باختری اراک به سن کرتاسه میانی در زون ساختاری سنندج-سیرجان واقع شده است.این توده دارای طیف ترکیب سنگ شناختی شامل:کوارتز دیوریت،گرائودیوریت تونالیت و دایک های مونزوگرانیتی می باشد که در سنگ های دگرگونی ناحیه ای(سریسیتوشیست) تزری چکیده کامل

توده گرانیتوئیدی مزبور در 45 کیلومتری جنوب باختری اراک به سن کرتاسه میانی در زون ساختاری سنندج-سیرجان واقع شده است.این توده دارای طیف ترکیب سنگ شناختی شامل:کوارتز دیوریت،گرائودیوریت تونالیت و دایک های مونزوگرانیتی می باشد که در سنگ های دگرگونی ناحیه ای(سریسیتوشیست) تزریق شده است.قرار گرفتن نمونه ها در نمودارهای تمایز محیط زمین ساختی در محدوده گرانیت های کمان های آتشفشانی(VAG) و غنی شدگی نمونه ها از LILEs و تهی شدگی نسبی آنها ازHFSEs و نسبت بالایYbLa و همچنین YbTh (>5) بیانگر ماگماتیسم متاآلومین کمان های آتششانی (VAG) است،وجود آنکلاوهای سورمیکاسه(آندالوزیت،سیلیمانیتو ...)و مقدار نسبت ایزوتوپی حاکی از آلودگی شدید ماگمای حاصل از ذوب بخش گوه گوشته ای،پوسته اقیانوسی فرو رونده (بازالت دگرگون شده) با پوسته قاره ای می باشد،بنابراین احتمالا ماگمای ایجاد کننده این توده وایسته به ماگماتیسم کمان های آتشفشانی حاشیه قاره ها و در اثر فرانش ورقه نئوئتیس به زیر سکوی قاره ای ایران می باشد. پرونده مقاله

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20 - Calculating of Taftan volcano displacement using PSI technique and Sentinel 1 images
Mahdieh Shirmohamadi Seyed Mohammad Tavakkoli Sabour Parviz Zeaiean Firooz Abadi Javad Sadidi

10.30495/jrors.2024.2002141.1202

Taftan is a semi-active volcano located in southeast Iran with many craters. The main objective of this study is to investigate whether subsidence or uplift in Taftan Peak. 58 Sentinel 1-A images acquired from January 2015 to December 2020 in the ascending orbit mode, a چکیده کامل

Taftan is a semi-active volcano located in southeast Iran with many craters. The main objective of this study is to investigate whether subsidence or uplift in Taftan Peak. 58 Sentinel 1-A images acquired from January 2015 to December 2020 in the ascending orbit mode, and 102 Sentinel 1-A Sentinel 1-B images acquired from October 2014 to June 2020 in the descending orbit mode were preprocessed for this purpose. The interferograms with the permanent scatterer interferometry (PSI) method were created using SARPROZ and StaMPS softwares, in which atmospheric corrections were made automatically, and then the surface displacement of Taftan volcano estimated.The Line of Sight (LOS) displacement corresponding to the uplift was 0.5 mm to 1 mm yr-1 for the ascending orbit and 1 mm yr-1for the descending orbit. Because no GPS station was close to Taftan volcano, the GPS measurements of one station located in the study area (Saravan station) was used to check the accuracy of PSI method. The GPS station of SARAVAN has situated inside the town ,and it is appropriate to use and analyze PSI technique in this station. As a result, the researchers found that the PSI method is in accordance with the GPS data. پرونده مقاله

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21 - ارزیابی توانمندیهای ژئوتوریستی گل فشانها بر اساس مدل پرالونگ در راستای توسعه پایدار( مطالعه موردی: گل فشان های جنوبشرق دریای خزر)
صدرالدین متولی

چکیده ژئوتوریسم نوعی گردشگری است که به حفظ یا تقویت ویژگی های جغرافیایی شامل فرهنگ، زیباشناسی، میراث زمین و غیره می پردازد. یکی از مهمترین مسائل در این خصوص،عدم شناخت جاذبه های ژئوتوریستی وبی توجهی به آنست.یکی از این جاذبه ها ،گل فشان های کرانه جنوب شرقی دریای خزر واقع چکیده کامل

چکیده ژئوتوریسم نوعی گردشگری است که به حفظ یا تقویت ویژگی های جغرافیایی شامل فرهنگ، زیباشناسی، میراث زمین و غیره می پردازد. یکی از مهمترین مسائل در این خصوص،عدم شناخت جاذبه های ژئوتوریستی وبی توجهی به آنست.یکی از این جاذبه ها ،گل فشان های کرانه جنوب شرقی دریای خزر واقع در استان گلستان بنام های گل فشان نفتلیجه، قارنیاریق تپه و اینچه برون می باشنداین تحقیق با هدف معرفی ویژگیهای ژئوتوریستی این گل فشان ها صورت گرفته که خود می تواند ارزش درمانی واقتصادی داشته باشد.روش این تحقیق از نظر هدف کاربردی و از نظر ماهیت توصیفی-تحلیلی ومیدانی است. به منظور ارزیابی و رتبه بندی عیارهای موجود در مکان های ژئومورفولوژیکی گل فشان ها از روش پرالونگ استفاده شده است. جهت دستیابی به این منظور نقشه های توپوگرافی و زمین شناسی، نتایج حاصل از بازدیدهای میدانی و پرسشنامه به عنوان داده ها و ابزارهای اصلی پژوهش مورد توجه قرار گرفته اند. نتایج حاصل از روش پرالونگ نشان داد که هریک از گل فشان ها(گل فشان قارنیاریق و گل فشان نفتلیجه و اینچه برون) به ترتیب با عیار گردشگری 46/0، 44/0، 43/0 از جاذبه گردشگری بالایی برخوردارند واز لحاظ اولویت بندی گل فشان قارنیاریق در اولویت برای گردشگری قرار دارد. براین اساس گل فشانها توان بالایی در زمینه جذب گردشگری دارا می باشند، نبود زیر ساخت های تبلیغاتی مناسب، نبود امکانات رفاهی برای گردشگران عامل اصلی گسترش نیافتن ژئوتوریسم منطقه است. کلمات کلیدی: ژئوتوریسم، گل فشان، روش پرالونگ، جنوبشرق دریای خزر پرونده مقاله

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22 - اندازه گیری صنعتی تاثیر آلودگی بر عملکرد عایقهای فشار قوی
محمدمهدی قنبریان محمدرضا شریعتی محمد محمدی

مقره‌های فشار قوی در معرض شرایط محیطی و اقلیمی مختلف قرار می‌گیرند. تأثیرات متقابل شرایط محیطی و آلودگی ایزولاسیون باعث می‌گردد عایق مقره‌ها خود بستر مناسبی جهت هدایت جریان گردیده و اثرات خود را بر سیستم‌های قدرت به جا بگذارد. در حال حاضر جهت تعیین سطح آلودگی محیط بر رو چکیده کامل

مقره‌های فشار قوی در معرض شرایط محیطی و اقلیمی مختلف قرار می‌گیرند. تأثیرات متقابل شرایط محیطی و آلودگی ایزولاسیون باعث می‌گردد عایق مقره‌ها خود بستر مناسبی جهت هدایت جریان گردیده و اثرات خود را بر سیستم‌های قدرت به جا بگذارد. در حال حاضر جهت تعیین سطح آلودگی محیط بر روی ایزولاسیون از اعداد تقریبی و تجربی استفاده می‌گردد. در نتیجه فواصل خزشی در بعضی مناطق با شرایط محیط متناسب نبوده و زیر حد طراحی قرار می‌گیرد. در این مقاله با اندازه‌گیری دوره‌ای ESDD و NSDD از دو روش دستگاه‌های اندازه‌گیر جهت‌دار آلودگی DGG جهت سنجش شدت آلودگی محیط بر روی ایزولاسیون و دستگاه OLCA جهت نمایش و ثبت جریان نشتی مقره معیارهای مناسبی جهت میزان و نوع آلودگی استفاده گردیده است. پرونده مقاله

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23 - Silurian undersea basalts in VMS mineralization in the North-East of Shahrood
Abodelreza Jafarian

The Soltan-Meydan basaltic suite contains a range of undersea mafic volcanic rocks whose stratigraphy position indicates lower Paleozoic (Silurian). In geology of Iran it has been named Soltan-Meydan Formation. However, Tectono-magmatic aspects of this suite and their r چکیده کامل

The Soltan-Meydan basaltic suite contains a range of undersea mafic volcanic rocks whose stratigraphy position indicates lower Paleozoic (Silurian). In geology of Iran it has been named Soltan-Meydan Formation. However, Tectono-magmatic aspects of this suite and their relationship with copper mineralization have not been studied yet. The aim of this study is to clarify these relationships. Out of three traverses of this suite more than 150 rock samples were collected and their thin sections were studied. 14 relatively fresh samples were selected for the purpose of geochemical analysis of major and trace plus REE elements. Thin section studies indicate a wide range of hydrothermal alterations, in which Chloritization is the most altered mineral. The Soltan-Meydan volcanic suite represents within-plate magmatism which seems to have erupted in the extensional regime. Some samples with more than 1% copper concentration contain copper sulfide mineralization. In addition, samples with high concentration of Zn and Pb are common figures in most whole rock analyses. Copper sulfides, hydrated copper carbonates, iron oxides and jasper are accompanied by two types of associations of hydrothermal alteration: a) high temperature associations and b) low temperature associations. Consequently, they may have generated volcanic massive sulfide (VMS) deposits in the mentioned suite. پرونده مقاله

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24 - Study of the Bryozoa of the lower part of the Jamal Formation in Bazman region (Sarab section)
Hamed Yarahmadzahi Andrej Ernst

To study the Bryozoa and the stratigraphy of Permian rocks in the Bazman region an east-west stratigraphic section was studied. The Sarab section, which takes its name from the Sarab River, is located on the southern slope of the Bazman Volcano. The rocks of this sectio چکیده کامل

To study the Bryozoa and the stratigraphy of Permian rocks in the Bazman region an east-west stratigraphic section was studied. The Sarab section, which takes its name from the Sarab River, is located on the southern slope of the Bazman Volcano. The rocks of this section with a thickness of 202 m. are divided into 7 informal rock units, where the lower boundary has discordance with carboniferous sediments, and the upper boundary is faulted. Based on the microfossils and the Bryozoa, the age of the lower part of the Jamal Formation is Bolorian. In this study, three genera and species were identified, one of which has been reported for the first time in Iran. Fistulipora timorensis ( Bassler 1929), * Strablascopora cf. germana (Bassler 1929) *Filiramoporina sp., Streblotrypa ( Streblascopora)marmionensis (Etheridge 1926). پرونده مقاله

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25 - بررسی اثر خاکستر آتشفشان و هماتیت بر برخی خصوصیات رشدی گیاه سورگوم در شرایط آزمایشگاهی
مهناز نارویی علی اکبر عسکری

آزمایش حاضر به منظور بررسی تأثیر هماتیت و خاکستر آتشفشان بر برخی صفات رشدی و فیزیولوژیک سورگوم به صورت فاکتوریل، در قالب طرح کاملا تصادفی با 9 تیمار و 3 تکرار اجرا گردید. تیمارها شامل خاکستر آتشفشان در سه غلظت (0، 25/0 و 5/0 گرم)، هماتیت در سه غلظت (0، 25/0 و 5/0 گرم) ب چکیده کامل

آزمایش حاضر به منظور بررسی تأثیر هماتیت و خاکستر آتشفشان بر برخی صفات رشدی و فیزیولوژیک سورگوم به صورت فاکتوریل، در قالب طرح کاملا تصادفی با 9 تیمار و 3 تکرار اجرا گردید. تیمارها شامل خاکستر آتشفشان در سه غلظت (0، 25/0 و 5/0 گرم)، هماتیت در سه غلظت (0، 25/0 و 5/0 گرم) بود. نتایج نشان داد در تیمار آتشفشان بزرگترین طول ریشه چه و ساقه چه در تیمار نیم گرم خاکستر به ترتیب با میانگین 82/4 و 11/4 سانتی متر و کمترین میانگین در هر دو صفت مذکور مربوط به تیمار عدم استفاده از خاکستر بود، همچنین در تیمار هماتیت بزرگترین ریشه چه و ساقه چه در تیمار نیم گرم هماتیت به ترتیب با میانگین 46/3 و 84/2 سانتی متر به دست آمد. در تیمار آتشفشان بیشترین وزن خشک ریشه چه و ساقه چه در تیمار نیم گرم خاکستر با میانگین 02/0 گرم و کمترین میانگین در هر دو صفت مذکور مربوط به تیمار عدم استفاده از خاکستر به ترتیب با میانگین 007/0 و 008/0 گرم بود، همچنین در تیمار هماتیت بیشترین وزن خشک ریشه چه و ساقه چه در تیمار نیم گرم هماتیت به ترتیب با میانگین 016/0 و 017/0 گرم به دست آمد. بیشترین غلظت کلروفیل a، b و کل در تیمار 5/0 گرم خاکستر به ترتیب با میانگین 67/0، 84/0 و 51/1 میلی گرم بر گرم وزن تر گیاه بود. استفاده از کودهای مغذی نسبت به عدم مصرف این کودها، اثر بیشتری بر خصوصیات رشدی سورگوم داشت، حتی مقادیر صفات اندازه گیری شده به دست آمده در این تیمارها بیش از 100 درصد نسبت به شاهد بود. پرونده مقاله

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