Petrofabric survey and mineralchemistryof amphibole in metamorphic complexes in Sanandaj-Sirjan zone
محبوبه
جمشیدی بدر
استادیار گروه زمین شناسی، دانشگاه پیام نور
author
text
article
2015
per
Khajoo metamorphic complex is located in the south-east of the Sanandaj–Sirjan metamorphic zone and Soursat metamorphic complex is located in the north-west of Sanandaj–Sirjan metamorphic zone. Amphibole – in these rocks – exists in garnet amphibole and amphibole schist with different fabrics that consists of oriented nematoblastic, shearing, cataclastic, acicular amphibole needles with central assemblage and cross growth, along to the C-axis. The state of the central assemblage and the cross growth of amphibole minerals related to grain boundary diffusion creep processes and simultaneous metamorphic process that is so-called Garbenschiefer texture. Garbenschiefer texture in the Soursat Complex is made up by shearing and large–scale folding and simultaneous regional metamorphism, and also in the Khajoo zone related to shearing of strike–slip faults and simultaneous regional metamorphism. Mineral chemistry of amphibole in garnet amphiboles is in the range of ferro–hornblende to ferro–tschermakite hornblende and also the schist amphiboles with different minerals and different fabrics is in the range of magnesio–ferro hornblende to tschermakite–ferro-tschermakite hornblende. The reason for chemical differences between amphibole mineral in garnet amphiboles and amphibole schists are due to variation between their protolits. There is no significant relationship between different fabrics and chemistry of amphibole minerals.
Researches in Earth Sciences
Shahid Beheshti University
2008-8299
6
v.
2
no.
2015
1
15
https://esrj.sbu.ac.ir/article_95579_ee1200913ab83a7435ba7432a8d2acdb.pdf
On the occurrence of analcime in the tephritic rocks in the Bozghush Mountains, north of Miyaneh, northwest of Iran
عیسی
آزادی
دانشجوی دکتری زمین شناسی، دانشکده علوم زمین، دانشگاه شهید بهشتی
author
محمد
رهگشای
دانشیار دانشکده علوم زمین، دانشگاه شهید بهشتی
author
سعید
علیرضایی
دانشیار دانشکده علوم زمین، دانشگاه شهید بهشتی
author
محمد هاشم
امامی
دانشیار سازمان زمین شناسی و اکتشافات معدنی کشور
author
text
article
2015
per
Volcanic rocks of upper Eocene age with tephritic to phono-tephritic composition are widespread in the Bozghush Mountains, NW of Iran.These volcanic rocks are occur both as lava flowd above a megaporphyritic andesite (middle Eocene age?) as well as small lenses within the volcaniclastic rocks. The rocks are porphyritic in texture and consist of phenocrysts of pyroxene, plagioclase, alkali feldspar, analcime, olivin, apatite and minor leucite in a fine-grained and glassy matrix. The analcime in these rocks occurs as an isotropic mineral 0.5 mm to 1 cm in diameter. Enrichment of the studied rocks in Sr, the absence of hydrous primary igneous minerals such as amphibole or biotite, lack of Na-pyroxene, the homogenous nature of the analcime and irregular cracks in the analcime indicate that the analcime crystals in volcanic rocks of the Bozghush Mountains formed by ion-exchange pseudomorphous replacement of primary leucite either during cooling and crystallization, or shortly afterwards.
Researches in Earth Sciences
Shahid Beheshti University
2008-8299
6
v.
2
no.
2015
16
30
https://esrj.sbu.ac.ir/article_95594_64b8839e746b6ac9df8dac9bc5627c93.pdf
Geochemistry and Petrogenesis of the Intrusive Rocks, Mehrabad area, East Ardestan
علی
کنعانیان
استاد دانشکده زمین شناسی، پردیس علوم، دانشگاه تهران
author
حامد
علی اشرف زاده
کارشناسی ارشد دانشکده علوم زمین، پردیس علوم، دانشگاه تهران
author
فاطمه
سرجوقیان
استادیار گروه زمین شناسی، دانشکده علوم، دانشگاه کردستان
author
جمشید
احمدیان
استادیار گروه زمین شناسی، دانشگاه پیام نور
author
text
article
2015
per
Mehrabad intrusive rocks, with probably Oligocene- Miocene age, located in the southeast of Ardestan, at the middle part of the Urumieh-Dokhtar magmatic belt. These rocks consist of granite, granodiorite, tonalite and quartz-monzodiorite that injected in the Eocene volcanic rocks of the area. Based on geochemical data, these intrusive bodies are calc-alkaline, meta-aluminium and I-type granitoid. Primitive mantel-normalized and condrite-normalized of trace elements and rare elements patterns indicate enrichment in the LREE and LILE compared with HREE and HFSE and pronounced negative anomalies in Eu, Nb, Ti and P in the studied samples. Such geochemical characteristics along with position of samples on the various tectonic discrimination diagrams indicate that formation of these rocks are related to the subduction zone in the active continental margin. Geochemical evidences such as high SiO2, low Mg# and transitional elements, also Nb/La, Nb/Ta, Ti/Zr, Nb/Ce and (La/Sm)naverage ratios and magmatic evolution discriminantion diagrams show that lower crust with meta-basalatic, meta-tonalitic and amphibolitic composition had played an important role in the formation of the granitic bodies of the Mehrabad region that generated by heat from partial melting of mantle at subduction zone.
Researches in Earth Sciences
Shahid Beheshti University
2008-8299
6
v.
2
no.
2015
31
50
https://esrj.sbu.ac.ir/article_95604_7ef287fc96d75c1e4ae625ddda020582.pdf
Characteristics of mineralogy, geochemistry and genesis conditions of Damghan fluorite deposit
مریم
ریاحی ماه
کارشناس ارشد زمینشناسی اقتصادی، دانشکده علوم زمین، دانشگاه دامغان
author
علی اکبر
حسن نژاد
استادیار زمینشناسی اقتصادی، دانشکده علوم زمین، دانشگاه دامغان
author
قربان
وهاب زاده کبریاء
استادیار زمینشناسی اقتصادی، دانشگاه کشاورزی و منابع طبیعی ساری
author
text
article
2015
per
Damghan fluorite deposit (south of Aresk) is located in the north -west of Damghan. This deposit is limited to the Arsk Mountains and from south it limited to the Atary fault. The mineralized zone is located in member 1 of the mila formation which is mostly dolomite along with interbeds of marl and yellow shal (yellow shal has the same age as middle Cambrian). Fluorite mineralization is mostly white color and a lesser amount with violate color and it is occurred as vein or open space filling. Along with fluorite mineralization, other minerals could be seen as sulfide minerals (like galena, pyrite, chalcopyrite, coveline) and also cerussite minerals, iron hydroxides, calcite and barite .According to the micro thermometry data carried out on fluid inclusions of white and violate fluorite, the temperature domain of homogenization is changing between 100 to 360 ° C and the salinity domain of mineralizing fluid is changing between 0.2 to 20.2 wt% NaClequ.. Evidence shows that fluorite mineralization probably occurred from mixing of hydrothermal fluid with meteoric and basinal fluids in reducing conditions.
Researches in Earth Sciences
Shahid Beheshti University
2008-8299
6
v.
2
no.
2015
51
64
https://esrj.sbu.ac.ir/article_95613_ccf3788fb66863bcb54c9ca01dddc9ff.pdf
Distinguishing Desert Environments by Ecogeomorphic Thresholds
زهرا
عبدالله زاده
دانشجوی کارشناسی ارشد مدیریت مناطق بیابانی، دانشگاه فردوسی مشهد
author
علیرضا
راشکی
استادیار دانشکده منابع طبیعی و محیط زیست، دانشگاه فردوسی مشهد
author
text
article
2015
per
According to the high diversity of vegetation, soil and bare rock patterns in the desert ecosystem and non-desert districts, distinguishing these areas is difficult. The approach used in this research introduced an ecogeomorphic view based on inverse recovery and erodibility potential to identify desert zones. The recovery/erodibility ratio can change the ecological resilience of ecosystem which shows resistance degree of system to environmental disturbances. The aim of this study was distinguishing desert environment based on eco-geomorphic boundries in Khorasan Razavi province as critical region to desertification process in Iran. In view of this four maps including lithology, vegetation cover, soil and isohyet were provided for analyzing the changes of recovery and erodibility ratio. The TM/ETM+ imagery data, geological map and soil map in scale 1:250'000 were used to prepare layers. An unsupervised classification was applied based on MODIS imagery data which shows eco-geomorphic dynamics along climatic/lithologicgradient.A zone as case study was selected where located in Lut and Sabzevar geological blocks. The climatic and topographic gradients were main reasons for choosing this case study in the KR province. Ecological and geomorphologic changes confirmed the erodibility - recovery oscillations in the study area. Results indicated two ecogeomorphic thresholds delineated based on characteristics of lithological, soil, and vegetation cover, rainfall fluctuations. The transition shows an ecogeomorphic transition between non-desert to semi-desert environments and a transition between semi-desert to desert region.
Researches in Earth Sciences
Shahid Beheshti University
2008-8299
6
v.
2
no.
2015
65
83
https://esrj.sbu.ac.ir/article_95623_0b1d3de0c8ea1474d947db72d01d9080.pdf
Evaluation of neo-tectonic activities in Ali Abad chayHorand watershed based on tectonic indicators (SL- BS- FD- BR)
فریبا
اسفندیاری
دانشیار ژئومورفولوژی، گروه جغرافیا، دانشگاه محقق اردبیلی
author
برومند
صلاحی
دانشیار آب و هواشناسی، گروه جغرافیا، دانشگاه محقق اردبیلی
author
رسول
حسن زاده
کارشناس ارشد هیدروژئومورفولوژی، دانشگاه محقق اردبیلی
author
text
article
2015
per
Phenomena’s which are the aim of the research in the neo-tectonic filed including the all factors, process and functions that are based on the earth new activates and created geomorphic by this activities. Evaluation of neo-tectonic activities based on tectonics indicators on Ali-Abad cay Horand watershed is the topic of this discussion in this research.The recognizing and proofing of neo-tectonic activities and represent the proportion of neo-tectonic activities in different part of watershed was the aim of this study.The method was that at the firstneo-tectonic activities in the watershed distinguishaccording the on the four types tectonic indicators include (FD, SL, BR) and averaged of all indicators. Then we proofed neo-tectonic activities in this watershed and based on the indicators final finding was existence of neo-tectonic activities in the watershed, for these reasons, we used the different data for example: topography and geology maps 1:50000 & 1:100000, satellite images an Slop- Fault- Hydrology-DEM-Tin maps, Arc-GIS software. Results showed that watershed neo-tectonic activities based on LAT indicators includes: 50% active- 30% semi-active basin and 20% was inactive that all of neo-tectonic activities observed along major fault in the sense of geographic information system (GIS), revealed that the neo-tectonic activities of Ali abad cay watershed active along three major fault and most minor faults and also watershed hydrology system compliance whit fault. We can conclude that authorities and planners should consider these geomorphologic evidence and phenomena in local and regional planning.
Researches in Earth Sciences
Shahid Beheshti University
2008-8299
6
v.
2
no.
2015
84
99
https://esrj.sbu.ac.ir/article_95635_ea34e444e3409daa8b2349dbf98cdc09.pdf
The effect of land use on soil quality in western part of Tehran
کاظم
نصرتی
دانشیار گروه جغرافیای طبیعی، دانشکده علوم زمین، دانشگاه شهید بهشتی
author
مونا
مجدی
دانشآموخته کارشناسی ارشد ژئومورفولوژی، دانشکده علوم زمین، دانشگاه شهید بهشتی
author
text
article
2015
per
One of the main objectives in urban environment is to guarantee a high level life quality for citizens by improving environment's quality where the level of pollution does not cause harmful effects on human health and other parts of biological system. Western part of Tehran was chosen as the case study and three land uses (agricultural, park, vacant lot) were recognized there. 20, 16 and 20 samples were collected from these land uses respectively. Based on assessment's purposes lime, pH, EC, total nitrogen, phosphorus, potassium, sodium, organic carbon, soil texture, bulk density, saturated soil percent and available water were measured in laboratory. Statistical analyses using One-way ANOVA indicated that organic carbon, total Nitrogen, sodium, phosphorus, Lime and potassium have significant changes in different land uses. Factor Analysis identified five factors that explained for 72.62 % of the variance. Finally, the soil quality model was determined based on the variables which have the most communality using redundancy analysis and discriminant function analysis. The results showed that organic carbon, lime, pH, P, BD and TN have the highest canonical coefficient and therefore, these variables are the effective parameters on urban soil quality indicators.
Researches in Earth Sciences
Shahid Beheshti University
2008-8299
6
v.
2
no.
2015
100
113
https://esrj.sbu.ac.ir/article_95585_8f6607d7649f4683799a12333acb57aa.pdf