فهرست مطالب

نشریه کواترنری ایران
پیاپی 20 (زمستان 1398)

  • تاریخ انتشار: 1398/09/10
  • تعداد عناوین: 7
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  • هما رستمی، قاسم عزیزی*، سعید بازگیر، حجت دارابی، مهران مقصودی، راجر جان متیوس صفحات 423-447

    جهت بازسازی شرایط محیطی و اقلیم دیرینه، مربوط به پلییستوسن پسین و هولوسن (30000 سال گذشته)، در زاگرس مرکزی، از تالاب هشیلان در کرمانشاه مغزه های رسوبی تا عمق 5/5 متری برداشته شد و با استفاده از روش مالتی پروکسی (پذیرفتاری مغناطیسی، جرم کاهی گرمایشی، سن سنجی و ژیوشیمی) مورد مطالعه و آنالیز قرار گرفت .  نتایج نشان دهنده آن بود که دوره پلیستوسن پایانی و LGM با شرایط اقلیمی سرد و خشک و طوفان های گرد و غبار در منطقه همراه بوده است. شرایط اقلیمی مذکور با شروع دوره گرم و مرطوب در 18000 سال قبل به پایان رسید که ، با دوره اقلیمی  گرم و مرطوب بولینگ آلرود مطابقت زمانی داشته است. هولوسن پیشین با شرایط اقلیمی نسبتا مرطوب به همراه رخدادهای سرد و خشک اقلیمی 2/9 و 2/8 و هولوسن میانی با شرایط اقلیمی گرم و مرطوب تا 5000 سال قبل در منطقه شناسایی شد. همچنین رخدادهای خشک موسوم به  2/4 و 2/3 با افزایش طوفان های گرد و غبار در منطقه تشخیص داده شد. نتایج نشان داد رخدادهای اقلیمی شناسایی شده در منطقه با رخدادهای شناخته شده در نیم کره شمالی مطابقت داشته و از یک الگوی مشابه پیروی می کند.

    کلیدواژگان: آب وهوای دیرینه، خورتابی، رخداد اقلیمی، زاگرس مرکزی
  • محسن سلیمان زاده، فرهاد خرمالی*، محمد سهرابی، رضا قربانی نصرآبادی، مارتین کهل صفحات 449-466

    پوسته‏ های زیستی نقش قابل توجهی در تثبیت تپه‏های شنی ایفا می‏کنند. پوسته‏ های زیستی گلسنگی و فیزیکی پراکنش گسترده ای بر تپه‏های شنی اوایل هولوسن در شمال استان گلستان دارند. مطالعه ‏ای با هدف بررسی تاثیر پوسته‏ های زیستی گلسنگی بر خصوصیات خاک سطحی و در نتیجه تکامل و پایداری این تپه ‏های شنی انجام شد. نمونه ‏برداری از خاک‏های تحت پوشش سه گونه گلسنگی انجام و برخی خصوصیات فیزیکیوشیمیایی و بیولوژیکی خاک اندازه‏ گیری شد. نتایج نشان داد حضور پوسته‏ های زیستی و فیزیکی خصوصیات سطح خاک را تغییر می‏دهند. درصد مقادیر در اندازه شن ریز و سیلت درشت در خاک‏ها تحت پوشش گلسنگ بیشتر از پوسته‏ های فیزیک است. به نظر می‏رسد مورفولوژی و ساختار پوسته‏ های زیستی گلسنگی سبب به دام انداختن ذرات در اندازه شن ریز و سیلت درشت شده است. خاک‏های تحت پوشش گونه های مختلف گلسنگ دارای مقادیر کربن آلی، کربوهیدرات، و پایداری خاک دانه ‏های بیشتر نسبت به پوسته‏ ها فیزیکی بودند. هدایت الکتریکی به مقدار قابل توجهی در خاک‏های تحت پوشش گونه ‏های گلسنگ نسبت به پوسته‏ های فیزیکی کاهش نشان داد. به نظر می‏رسد حضور پوسته‏ های زیستی بر خاک‏های مشتق شده از رسوبات شنی اوایل هولوسن نقش مهمی در بهبود خصوصیات خاک و به دام انداختن گرد و غبار ایفا می‏کنند.

    کلیدواژگان: پایداری خاک، تپه های شنی، خصوصیات خاک، گلسنگ، هولوسن
  • مجتبی یمانی*، ابوالقاسم گورابی، مهیار حقیقی صفحات 467-491

    سیستمهای ساحلی یکی از سیستمهای پیچیده محیطی هستند که تحت تاثیر فرایندهای هیدرودینامیکی خشکی و دریا دچار تغییرات سریع میشوند. در این پژوهش برای تعیین سلولهای ساحلی به منظور مدیریت بهینه محدوده ساحلی بین بندر انزلی تا چالوس نگاهی سیستمی به این موضوع شد. نقشه های توپوگرافی و ژیومورفولوژی، داده های هیدرولوژی رودخانه ها، داده های هیدرودینامیک دریا، و تصاویر ماهواره ای مهمترین داده های پژوهش بودند. تجزیه و تحلیل داده ها با استفاده از ارزیابی حجم دبی جریان و رسوب، شناسایی عمق فعال رسوبی، تحلیل دینامیک موج و جریان با نرم افزارهای Arc GIS 10.5 و Excel 2016 انجام شد. طی این مراحل طول نوار ساحلی به 4 سلول رسوبی تفکیک شد. هر یک از این سلولها، با توجه به جریان رسوب و شرایط محیطی و سایر عوامل تاثیرگذار، متمایزند. نتایج نشان داد رودخانه ها از پدیده های مهمی هستند که در تفاوت ژنتیکی سلولهای رسوبی، در کنار سایر عوامل ژیومورفولوژیکی، نقشی مهم در تعیین سلولهای ساحلی داشته اند. هر یک از سلولها، با توجه به ماهیت و فرایندهای همگن، یک واحد مدیریت ساحلی شناسایی شدند. بدیهی است سلولهای تعیین شده میتوانند در مدیریت بهینه ساحل، مدیریت یکپارچه ساحل، و همچنین کنترل آثار مخرب ناشی از فرایندهای ساحلی موثر باشند.

    کلیدواژگان: ژئومورفولوژی ساحلی، ساحل بندر انزلی، ساحل چالوس، سلول ساحلی، مدیریت ساحلی
  • امیر ظهریه، محمود الماسیان*، محسن پورکرمانی، علیرضا شهیدی صفحات 493-515

    منطقه مورد بررسی مجموعه ای از ساختارهای زمین ساختی، به ویژه شکستگی های گوناگون و گسل ها و انواع چین خوردگی، را در خود جای داده است. ساختار ها با سازوکار خاص متاثر از تنش ها (فشارشی کششی) بوده اند. بر اساس شواهد زمین شناسی موجود در همه واحدهای سنگی سازند کرج و نهشته های آبرفتی کواترنری در پهنه گسلی شمال تهران، اعم از خش لغزها و ساختارهای C -S، سازوکار گسل شمال تهران تا قبل از پلیوسن به صورت مورب لغز راست گرد با مولفه عادی و پس از نیوژن به صورت مورب لغز می باشد که در برخی مناطق مولفه معکوس غالب است و در برخی مناطق مولفه راستالغز چپ گرد غالب  می باشد . تحولات زمین ساختی گستره مورد مطالعه با یک مدل قابل ارایه است. بر اساس این مدل، گستره بین دو گسل شمال تهران و مشاء به صورت یک ابر دوپشته در حال چرخش راست گرد (ساعت گرد) است. موقعیت تنش اصلی σ1 (عمود بر محور چین خوردگی یا راستای کوتاه شدگی) در زمان تشکیل ساختارهای شکل پذیر منطقه راستای شمال باختر- جنوب خاور داشته است.

    کلیدواژگان: پالئواسترس، پهنه گسلی شمال تهران، زون گسلی، سازند کرج
  • عباس مقدم*، احمد سرخوش، حسین داودی، لقمان احمدزاده شوهانی، رامین یشمی صفحات 517-540

    که در آن پژوهش های دامنه داری برای شناسایی جوامع پیش ازتاریخی صورت گرفته به مناطق فرادست (نواحی بلند) و فرودست (نواحی پست) محدود شده است. شواهد موجود حکایت از آن دارد که پهنه های وسیع آبی در شمال و جنوب ایران و سرزمین های مجاور آن از دیرباز یکی از کانون های جذاب برای جوامع انسانی بوده است. برخی از انگاره های پیشین این باور را بین پژوهشگران ایجاد کرده است که به دلیل نوسان پی در پی سطح آب دریا نباید انتظار وجود زیستگاه های پیش ازتاریخی در سواحل خلیج فارس را داشت. شواهد زمین شناسی و به ویژه باستان شناسی یکی پس از دیگری اشتباه چنین انگاره هایی را بر ما روشن می سازد. تپه تهماچی یکی از زیستگاه های هزاره پنجم پیش ازمیلاد در دشت لیراوی (دیلم) است که علاوه بر نزدیکی به رودخانه آب شیرین زندارون کمتر از پنج کیلومتر تا ساحل فعلی خلیج فارس فاصله دارد. ارزیابی صورت گرفته نشان می دهد تهماچی، با بیش از ده متر نهشته فرهنگی، یک زیستگاه موقتی در ساحل دریا نبوده است. بنابراین، نخستین بار است که در سواحل شمالی خلیج فارس مدرک مهمی برای توضیح خط ساحلی خلیج فارس در هزاره پنجم پیش ازمیلاد به دست آمده است.

    کلیدواژگان: تپه تهماچی، خلیج فارس، دشت لیراوی، زیستگاه های پیش ازتاریخی، نوسان دریا
  • فرهاد پیرمحمدی علیشاه* صفحات 541-559

    آتشفشان سهند در کمربند ولکانو پلوتونیک ارومیه دختر واقع شده و ساختمان آن شامل تناوبی از گدازه ها و مواد آذرآواری مختلف است. این آتشفشان از نظر سن نسبتا جوان (میوسن تا پلییستوسن) است؛ طوری که بر اساس مطالعات رخساره ای می‏توان ساختمان آتشفشان سهند را در چهار رخساره تفکیک کرد. رخساره مرکزی در محل کالدرا واقع شده و واحدهای سنگی خاصی، چون توده نفوذی نیمه ژرف دگرسان شده و برش های گدازه ای و دایک های حلقوی و شعاعی، دارد. رخساره نزدیک آتشفشان به صورت دیواره های پرشیب و مرتفع در اطراف کالدرا گسترش پیدا کرده و ساختار چینه ای را به خوبی نشان می دهد که در آن توالی های ستبر واحدهای آذرآواری ریزشی، خیزابی، جریانی، و گدازه به صورت متناوب قرار گرفته اند. رخساره میانی، با بیشترین گسترش، به طور عمده از مواد آذرآواری خیزابی، جریانی، گدازه، و لایه های متعدد لاهار تشکیل شده است. رخساره دور آتشفشان سهند ستبرای کمی دارد و شامل رسوبات رودخانه ای درشت دانه ای است که در اثر تحرک دوباره محصولات اولیه آتشفشان و حمل آن ها توسط رودخانه ها به وجود آمده اند. مطالعات رخساره ای نشان می دهد ساختمان آتشفشان سهند در اثر چندین فاز فورانی انفجاری ایجاد شده که برخی از آن ها با دخالت آب همراه بوده اند و فاصله زمانی زیادی میان فوران ها وجود نداشته است. ویژگی هایی چون جوش خوردگی شدید و رنگ نهشته های آذرآواری نشان می دهد این واحدها در زمان تشکیل دمای بالایی داشته و در خشکی تشکیل شده اند.

    کلیدواژگان: آتشفشان مرکب، رخساره آتشفشانی، سهند، کانی سازی کالدرا، مواد آذرآواری
  • فریدون قدیمی*، محمود میرزایی صفحات 560-579

    امروزه رسوبات کواترنری محل دفن پسماندهایی است که با آلودگی های خاک، آب، و هوا همراه است. محل دفن زباله اراک در بالادست چاه های آب آشامیدنی منبع آلاینده آب محسوب می شود. به منظور ارزیابی آلودگی رسوبات در محل دفن زباله 31 نمونه رسوب از سه گمانه تهیه و غلظت فلزات سنگین و پارامترهای فیزیکی و شیمیایی آن ها تعیین شد. برای تعیین عناصر آلاینده، غلظت فلزات سنگین با مقدار مرجع پوسته فوقانی مقایسه و شاخص های آلودگی مانند ضریب غنی شدگی، ضریب زمین انباشت، و درجه آلودگی فلزات سنگین تعیین شد. مطالعه حاضر نشان داد سرب، کروم، نیکل، مس، روی، آرسنیک، و جیوه از مرجع پوسته بالاترند و غلظت متوسط آن ها به ترتیب 32، 39، 64، 25، 73، 15، 15، و 6/6 میلی گرم در کیلوگرم است. رسوبات آلوده به آرسنیک و جیوه اند و درجه آلودگی آن ها در سطح و اعماق پایین گمانه ها از متوسط تا زیاد متغیر است. تجزیه وتحلیل عاملی نشان داد بین منگنز و سرب، نیکل، مس، و روی همبستگی مثبت وجود دارد. همچنین همبستگی بین ماده آلی با جیوه مثبت و با آرسنیک منفی است. بنابراین، منگنز و ترکیبات آلی نقش مهمی در توزیع فلزات سنگین در رسوب محل دفن زباله اراک دارند.

    کلیدواژگان: آلایندگی رسوبات، اراک، تحلیل عاملی، دفن زباله، فلزات سنگین
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  • Homa Rostami, Ghasem Azizi*, Saeed Bazgeer, Hojjat Darabi, Mehran Maghsoudi, Roger John Matthews Pages 423-447
    Introduction

    The study of lake sediments has been widely used in recent decades to identify past climate and environmental changes. Lake basins have significant spatial and temporal patterns and provide valuable evidences of physical and chemical changes. However, in general, the climate of the Holocene period has been more stable and uniform than previous glacial and interglacial periods. However, there have been many sudden climate events that have affected the lifestyles and activities of human groups. In this study, using the results of geological, climatological and archaeological studies, climate change and the environment of the Central Zagros from the Late Pleistocene to the present have been studied and reconstructed.

    Methods

    In this research, multi-proxy method has been used. The results of geochemical analyzes, magnetic susceptibility, chronology and palynology of sedimentary cores has taken from Hashilan wetland in Kermanshah were studied and analyzed.

    Results

    The results of the analysis showed that most of the identified Holocene climatic events in the world have also occurred in Central Zagros. In the last period of glaciation, the climatic conditions of this region were cold and dry with the predominance of physical erosion and the dominant vegetation of the region was steppe and Chenopodiceae. Before the onset of Younger Dryas event, there was a warm and humid period in the region that coincided with the hot and humid period of Boling Allerod in Europe. After the end of Younger Dryas cold event, the Early Holocene period began 11,000 years ago in the region. The Early Holocenechr('39')s humidity in the Central Zagros region was not enough to grow Quercus trees, and compared to Jordan and Turkey, the climate was drier. Due to changes in insolation (the amount of radiation received by the sun within 60 degrees north: (Milankovic cycle) and its increase in the northern hemisphere, the amount of radiation received by the northern hemisphere increased in the summer, which led to the expansion of Inter Tropical Convergence zone belts and Subtropical high pressures and the summer monsoons of the Indian Ocean zones became wider. In the Late Holocaust, the Zagros region was dominated by STHPs and received very little spring and summer rainfall due to the influx of high-pressure tropics. As the insolation reducing in the middle Holocene and the STHPs retreat to lower latitudes, the humidity entry from Atlantic Ocean and Mediterranean into the region increased, and quercus trees grew in the area during the wet period of 7,500 years ago. In Late Holocene, the intensity of dry climatic events has increased so much that the driest period was 3,200 years ago.

    Keywords: Climate event, Insolation, Central Zagros, Paleoclimate
  • Mohsen Solymanzadeh, Farhad Khormal*, Mohammad Sohrabi, Reza Ghorbani Nasrabadi, Martin Kehl Pages 449-466
    Introduction

    Biological soil crusts are a community of cyanobacteria, fungi, lichens, and mosses and play key roles in arid and semi-arid regions including carbon and nitrogen accumulation, soil fertility, dust capture, soil conservation and stability. Recent studies show that the formation of biological soil crusts on mobile dunes areas is extremely difficult due to low vegetation cover, strong sand flow activity, and soil surface instability. If sand activity is controlled by the wind and the soil surface is stabilized by cover establishment and/or mechanical factors, the biological and physical crusts gradually form on the soil surface. These soil crusts play an important role in establishment and evolution of sand dunes. Lichen biological soil crusts and physical crusts are widespread on early Holocene sand dunes in the north of Golestan province. The aim of this study was to investigate the effect of lichen biological soil crusts on surface soil properties and consequently evolution and stability of sand dunes.

    Materials and methods

    Sand dunes around the Alagol wetland located in the north of Golestan province were selected for this study. Lichen biological soil crusts species were collected after extensive filed study and transferred to the laboratory for identification. Three lichen species including Diploschistes diacapsis (Ach.) Lumbsch, Gyalolechia fulgens (Sw.) Søchting, Frödén & ArupFulgensia fulgens (Sw.) and Squamarina lentigera (Weber) were identified. After identification, soil samples were taken from two depths beneath lichen biological soil crusts and physical crusts. Then, soil samples were transferred to laboratory and some of physical, chemical and biological soil properties including total organic carbon, carbohydrate, calcium sulfate, equivalent calcium carbonate, mean aggregate diameter, particle size, pH and electrical conductivity were measured using standard methods. In addition, soil samples were taken from two meter depths (parent material) for particle size analysis. In this research, a completely randomized factorial design with three replications was used to analyze the data. The means were compared using LSD method at p < 0.05. SAS software was utilized to analyze the data, and the figures were drawn using Excel software and GRADISTAT (Version 8.0).

     Results and discussion

    The results showed that presence of lichen biological soil crusts and physical crust changes the surface soil properties. Soils derived from aeolian deposits beneath of various lichen biological soil crusts had higher total organic carbon, carbohydrate and mean aggregate diameter in comparison with physical crusts. D. diacapsis and S. lentigera species had improved physical, chemical and biological soil properties compared to G. fulgens species. The effect of biological soil crusts on soil properties decreased with increasing soil depth. There was a high correlation between mean aggregate diameter with total organic carbon and carbohydrate. Electrical conductivity strongly decreased in soils cover with D. diacapsis and S. lentigera species compared to physical crusts and G. fulgens species in two depths. Calcium sulfate was higher in soil covered by G. fulgens in comparison with D. diacapsis and S. lentigera species. The content of fine sand and coarse silt in soils covered by lichen biological soil crusts was higher than physical crusts. Whereas, the content of fine silt and clay content covered by physical crusts were higher or similar to lichen biological soil crusts. Parent material had greater particle size distribution in comparison with surface soils covered with biological soil crusts and physical crusts. These results show that soil crusts are formed in soils with finer particle size. Biological soil crusts can increase fine particle content with two mechanisms including capture dust and weathering soils. The secretion of extracellular polysaccharides (carbohydrate) and rough surface morphology of biological soil crusts may help to capture dust (fine sand and coarse silt). Soil pH and calcium carbonate were lower in soils covered with lichen biological soil crusts compared to physical crusts.

    Conclusion

    The presence of biological crusts on soils derived from early Holocene aeolian deposits apparently plays an important role in improving soil properties. Well-developed lichen biological soil crusts including D. diacapsis and S. lentigera species may significantly lead to establishment and stability of soils derived from early Holocene aeolian deposits. It seems that G. fulgens species grow better on coarse-grained soils with higher calcium sulfate content. Lichen biological crusts increase the mean aggregate diameter and consequently increase the stability of the soil surface.  Lichen biological soil crusts have an important role in dust capture and resulted in increased fertility of soils derived from early Holocene aeolian deposits.

    Keywords: sand dunes, lichen, soil properties, Holocene, soil stability
  • Mojtaba Yamani*, Abolghasem Gorabi, Mahyar Haghighat Pages 467-491
    Introduction 

    Due to the different geomorphological and morph dynamic forces of the coastal area, they form different areas. Each of these areas requires its own coastal management. While in our country, coastal management is done without considering the characteristics and coastal characteristics of each coast. In this study, in order to classify coasts and determine coastal cells, morph dynamic effects and sedimentary structures of riverbeds and seas have been used be taken; therefore, we are looking for the answer to the question of what are the coastal cells between Anzali port and Chalous and what are the boundaries of ta separation of these cells? And what are their uses in coastal management? The problem-solving method and answering research question is quantitative and using geomorphological and marine hydrodynamic data.     

    Materials and methods

    The study area is the distance between Bandar Anzali in Gilan province and Chalous city in Mazandaran province. Research data include geological data, river hydrodynamic data (annual flow and sediment discharge), marine hydrodynamic data (current and direction of the wave), regional elevation model (DEM) 12.5m, surface morphometric and topographic data including slope and gradient direction, surface data, the sea level is the active sedimentary depth data, the sedimentation of coastal sediments and the field observational data. The research tools included geological maps of 1:100000, topographic maps of 1:25000, images of sentinel 2 satellites, sedimentation models of hydrometric stations, high-speed wave data of Anzali port, Rudsar and Chalous. In the method of data analysis, first, the hydrometric characteristic (flow and sedimentation) of rivers and coastal sedimentation models using excel and GIS software. In the step, the determinants of sedimentary cell boundaries were consolidated. At this stage, the boundary separating boundaries that distinguished those from each other in terms of the mentioned features were drawn and the main sedimentary cells were determined. In the final step, the boundary of the cells on land and sea was determined. At this stage, for each cell, the cell boundary at the post cranium and its boundary at sea were determined.  

    Results and discussion

    The results of the overlap model showed that the range between Anzali port and Chalous consists of 4 main cell and 9 sub cells.  The first main cell is between Chalous port and Ramsar beach. The main characteristics of this cell are the change in the direction of flow after the failure of the wave to the east. The sedimentary reservoirs of this cell and the sediments of the rivers are lower than other cells, and the slope of the coast in these cells is higher than the other shores of the study area and research 1.1%.  The second main cell is the Ramsar cell to the clutch. Characteristics of this cell include the high rate of sedimentary inflow from the rivers in this cell and the flow of sediment rotation to the east are the main characteristics of this cell. Also, most of the river sediments in this cell are moving to the east and have accumulated in the distance between the estuary of the river and the middle of the Chabaksar to Qasemabad route. The third coastal cell is between Kalachai Rezamahleh and Amirabad region. In this part, due to the increase in altitude due to Alborz Mountain and the sudden increase of the slope and hard post-coastal formations, the coast has a small area. Also, the height of the wave and the direction of flow are to the west and move parallel to the shore. The boundary between the two cells in Kiasar is a man-made and rock-forming structure, but in Amirabad there is a sudden change in slope and a change in the direction of flow. The fourth cell is between Amirabad nose and Anzali port (Caspian port). In this cell, the main sand formation and most of the formations are composed of low plains and sedimentary plains resulting from sediments of Sefidrud River. In this cell, the movement of the current after the break of the wave is towards the west and has caused the sediments to move from the estuary of the rivers to its west. Also in this cell, due to the high flow and sedimentation of Sefidrood River, a wide area of ​​the coast is covered with ridges and coastal sands.  

    Conclusion 

    According to the research results, the sandy shores of the Sefidrud River and other rivers on the shores of Bandar Anzali to Chalous are among the most widely identified types of landforms. Only in Chalous, due to the high population density and low shoreline, human sandstones have undergone more changes than human and coarse-grained sands. Therefore, due to the fact that most of the study area has a high population density and also the lowlands of these areas have a small slope and height, if the climate changes and sea level rises with dangers such as flooding of lands and infrastructure. Coastal buildings, the destruction of various residential, industrial, office, educational and other facilities and buildings also threaten it. It is worth noting that the complexity of natural, physical and human activities in the coastal area makes it difficult to manage it, because this complexity has caused and will cause many problems in the coastal areas.

    Keywords: Coastal Geomorphology, Coastal Cell, Chalous Beach, bandar-E- Anzali Beach, Coastal Management
  • Amir Zohrieh*, Mahmoud Almasian, Mohsen Pourkermani, Alireza Shahidi Pages 493-515
    Introduction 

    The study area has various types of geological structures, especially various types of fractures and folds. Evidence indicates that Structures with specific mechanisms in this area have been affected by Compressional - Tensile tensions.  

    Materials and methods

    To determine the direction of stress in the fault zone north of Tehran, from various tectonic evidences including fault slip scratches, Conjugated faults and folds in the Eocene rock units of Karaj Formation and Quaternary alluvium was used. For this purpose measured structures Was analyzed using Tectonic FP software and Angelier software was used for paleostress analysis of the area.  

    Results and discussion

      According to geologic observations in Karaj formation units and Pleistocene-Holocene deposits of North Tehran fault zone including Slickenside and S-C fabrics, before Pliocene the fault mechanism was right-lateral strike-slip and after that it has changed to oblique-slip some parts the revers component  and in some other parts left-lateral strike-slip component dominates. The tectonic developments of the study area can be presented with a model. According to this model, the area between the two faults north Tehran and Mosha as a triangular block(Mega Duplex) is Turning right, This model is presented in accordance with the tectonic evidence presented below: The tectonic history of central Alborz in the study area is clearly evident and evidence of its compression N-S, NW-SE,NE-SW Has been left out, Seismic data recorded at the Institute of Geophysics of the University of Tehran shows the most seismic activity on the North Tehran Fault slope and its associated with the Mosha fault, By comparing the zoning of the area in terms of aggregation of tectonic structures and seismic data observed at the center of the study area, There is an elliptical basin that shows low tectonic activity. Given that the area is not Lithology significant, This phenomenon can be justified by the rotational model, So that the maximum stress and friction force is applied to the sides of this triangular block and the least to the center of the range, As a result, tectonic activity is minimized in the said area in the center. Axial surface of all folds harvested in Eocene rock units of Karaj Formation In the fault zone north of Tehran in sabu, Darkeh, Hesarak and Kan regions, they have an approximate northeast-southwest. Due to the geometric position of their axial surfaces for the stress of the region in the past, It was northwest-southeast. In the fault zone north of Tehran before Neogene in most areas of northwestern-southeastern stress And the mechanism of faults was straight-slip rectilinear and the time of stress direction change was Neogene. In the Can region, based on the geometric location of the scratches, the landslides were investigated And stretched folds in alluvial sediments of type C, which is the newest sedimentary unit in the region,The direction of tension in the region is northwest-southeast. Therefore, it can be said that in this area, after the Pliocene, the tension has not changed, unlike other parts of the fault zone north of Tehran. And the recent Northeast-Southwest tension has not affected it. This part of the fault is likely to be affected by a smaller local stress.Due to the adaptation of the trend and mechanism of faults harvested in the region with fractures (Riddle) Also, the existence of conjugate faults, the mechanism of strike-slip fault north of Tehran is confirmed. East-west pressure force must Folds with a north-south trend in the region have been created by examining the region, No wrinkles are seen with this trend. This feature can be due to the block rotation in the studied sheet,Between the two driving faults north of Tehran and Mosha with straight-slip components And has formed folds with a northwest-southeast trend.

    Keywords: Paleostress, Fault Zone, North Tehran fault zone, Karaj formation
  • Abbas Moghaddam*, Ahmad Sarkhosh, Hosyn Davoudi, Loqman Ahmadzadeh, Yashmi Pages 517-540
    Introduction

      Given the diverse characteristics of Iranchr('39')s geographical area, we know that the diversity of Iranchr('39')s natural landscape is not limited to the lowland and highland areas. Evidence suggests that large bodies of water in northern and southern Iran and its surrounding lands have long been one of the most attractive niches for human societies. Some misconceptions have led researchers to believe that due to successive fluctuations in sea level, one should not expect prehistoric habitats on the shores of the Persian Gulf. The new geological and especially archaeological evidence, one after the other, clearly leads us to clarify the previous assumptions. Tappe Tahmachi is one of the of the 5th millennium BCE settlements in the Lirawi (Dylam) Plain, which, in addition to being close to the Zendaroun freshwater river, is less than five kilometers from the current shores of the Persian Gulf. The assessment shows that Tahmachi, with more than ten meters of cultural accumulations, was not a temporary settlement on the coast. Therefore, for the first time on the northern shores of the Persian Gulf, significant evidence has been obtained to explain clearly the Persian Gulf coastline in the fifth millennium BCE.  

    Materials and Methods 

    Due to climate changes happened during the last ice age (appr. 70.000 and 17.000 years ago) sea levels were lower 120 meters than their current situation. Prior to these changes, the Persian Gulf did not exist as a body of shallow water as today. By joining three of the most important rivers in the Near East, i.e. Euphrates, Tigris and Karun, a largely extended river had formed that ran from current Arvand River (Shat al Arab) to the mouth of the strait of Hormoz. It is clear that such a river had a huge impact on human life especially during the village period. Researchers believe that seawater reached its current level in earlier times, and even reached a level higher than this about 6,000 BC, about 1 to 2 meters above the current level. Among the documents provided for the qualitative and quantitative explanation of the Persian Gulf coastlines, the distribution of prehistoric settlements and their remoteness and proximity to the sea are of great importance. In a narrative of the prehistoric settlements increase on the southern shores of the Persian Gulf, we will see that a significant number of sites have been found near the current coastline. However, this figure is not seen in the coastal areas north of the Persian Gulf, due to the lack of prehistoric sites near the northern coast of the Persian Gulf or extensive sea fluctuations in this area. We believe, the most important reason is the lack of purposeful archaeological research. Tahmachi prehistoric site is located in the Lirawi (Deylam) Plain, a flat, low-lying plain with a slope of less than 0.5% and 4,500 meters from the current shores of the Persian Gulf (Figure 2). As for the soil quality, if water resources are available and proper drainage is possible, we can expect the harvest of crops such as sugarcane in the surrounding areas of Tahmachi. Some areas of the plain have the potential to form salt marshes. Due to its proximity to the tidal range of the sea, the southern areas of the plain have high groundwater levels and saline soils. Hundreds of seasonal and permanent drainages have been formed from the heights of the Rag Sefid ridge to the sea due to the difference in height between the Rag Sefid and the Lirawi Plain, and especially the low point of the sea. In most gullys, water is seen when it is raining and, of course, otherwise it dries up. Meanwhile, some gullys have water all year round. Zendaroun River passes a short distance west of Tahmachi. The river originates from the Tonbata valley in the highlands of the Rag Sefid and finally flows into the Persian Gulf with great meanders in the Lirawi alluvial plain. Rivers such as Zendaroun are one of the sources used for desalination of current agricultural lands due to their fresh water content. Tahmachi, 39R417186.67 m E 3338440.23 m N, is located right on the east side of Zendaroun river and is located almost in the middle of a hypothetical straight line with a length of 10 km from the heights of Rag Sefid to the Persian Gulf coast (Figure 2). The compound consists of two north and south mounds that are located a short distance from each other (Figure 3). The height of the northern mound is 16 meters and the southern mound is 14 meters above sea level. The ratio of lands around two mounds: the southern lands of the area is about 7.25 meters and the northern lands are about 10 meters above sea level (Figure 4).

    Conclusion

    The presence of Tahmachi near the shores of the Persian Gulf has taught us important lessons. First: For decades, a very important actor (prehistoric sites) in the measurement of water fluctuations in the Persian Gulf has been ignored. Second, what has received less attention in prehistoric archeological literature is settlement diversity. However, available evidence has shown that not all settlements are necessarily functionally the same. Third, it may seem that due to the proximity to tidal fluctuations, soil salinity, heat and lack of rainfall, one should not expect any prehistoric habitat in coastal areas. Considering the Tahmachi pattern, we very much hope that surveys on the northern shores of the Persian Gulf will no longer be conducted in the same way as before, and that researchers will carefully study and assess the promising areas before making any predictions. In this case, we very much hope that the number of prehistoric settlements on the northern shores of the Persian Gulf will be much higher than the number identified so far.

    Keywords: Persian Gulf, Lirawi Plain, Tepe Tahmachi, Sea Water Flactuation, Prehistoric Settlements
  • Farhad Pirmohammadi Alishah* Pages 541-559
    Introduction 

    Sahand Volcano, with an area of ​​about 7200 km2, is a stratosphere located in East Azarbaijan Province, and since it has retained some of its original structure and volcanic facies due to its young age, its facies studies can be well studied. Understanding the mechanism of volcanic activity in this region, examining the possibility of various deposits and finding their exact location and recognizing related geological processes and separating urgent phases, shows the importance and necessity of epistemological studies in this volcano. The purpose of this study is to identify the facies of Sahand volcano and to achieve this goal, we have tried to identify and study the facies by using extensive field studies and introducing and describing the facies and volcanic products. 

    Materials and methods

    In order to properly understand the geology of Sahand volcano and to determine the relationship between different rock units and to study the epistemology by conducting field visits, geological features from the central part of Caldera to the walls and also from the outer parts to Caldera, by conducting several surveys. Various studies and sections were examined. Due to the fact that the domes of the last volcanic eruptions of Sahand volcano are mostly in the central and eastern part of the volcano, the sections worked in the central and eastern parts of the region are located. In the next step, by examining the facets of volcanic products and studying the sedimentary tissues and structures present in pyroclastic and opioclastic deposits of different sections, it was tried to use these tools to some extent to characterize the sedimentation environment and how Make the faces clear. 

    Results and discussion

    In the evolution of sedimentary basins close to volcanic centers, there is a complex relationship between processes such as subsidence of the basin, processes related to the evolution of volcanic arcs, and climate phenomena (Catonino 2004; Smis et al., 2002). Climatic phenomena have led to the re-emergence of volcanic deposits during eruptions and intermittent eruptions, and sedimentation has preserved evidence of how these processes have changed. This evidence is better preserved in areas with rapid subsidence (Catonino 2004; Leader 2000, Gaussorpe, and Incele 2000). One of the features of Sahand volcanic rocks is the very thick thickness of the products. It seems that volcanic eruptions in the Sahand region initially led to the formation of large volumes of emergency materials. Then, when volcanic activity has stopped, pyroclastic deposits and lavas are eroded and transported by river networks, and epic-plastic sequences are produced, and these deposits are generally processed by processes. Called epiclastic, they are transported and re-deposited (Cass and Wright 1987). Recent studies on sedimentation in sedimentary environments affected by explosive volcanic activity have shown that the alternation of sedimentation conditions with eruption and interstitial sedimentary conditions is the most significant factor influencing the formation of deposits. They are in these environments (Martina et al. 2006; Manasro et al. 2000; Katuka and Nakaju 2002; Nakayama and Yoshikawa 1997). Powerful erosion periods in volcanic areas are likely to be related to climate change (declining water levels, different types of plants along the range) or volcanic-structural changes in the region (Calcutta et al. 2007). Exploratory studies of volcanic products are very useful tools for understanding the nature of sedimentary environments at the time of eruption. Because volcanic rocks are formed in both continental and marine environments, describing the features of their epistemological form can provide valuable information about the characteristics of the sedimentation environment. And provide researchers with the type of environment and even the type and intensity of volcanic eruptions. 

    Conclusion

    Keywords Sahand Volcano is a stratovolcano that erupts its material from numerous scattered craters, and its volcanic activity has alternated with explosive and lava flows that have led to the formation of pyroclastic and lava deposits. The eruptions were mostly explosive and not far from each other, but during periods of eruption between volcanic eruptions, volcanic material was eroded by rivers and deposited on the riverbed or sedimentary basins of the low-lying continent. They were left deep. Chinological studies have shown that Sahand operated for a relatively long period of time, with its first volcanic activity beginning in the middle of the Miocene and continuing intermittently until the end of the Pleistocene. The first eruption in Sahand was very explosive and involved water interference. The reaction of water and acidic magma beneath the Earthchr('39')s surface caused huge ferromagmatic explosions, and pieces of host rocks, along with volcanic ash and Pamis, were thrown into the air, making Sahand the first product. The detection of this immediate phase is possible only by studying the medial facies, because the Azarvari deposits, which were the result of this eruption, have the best outcrops in this facies. Then the eruption stopped and erosive agents created holes in the surface of the flow deposits. These side effects are visible on the middle face. Subsequent immediate events, which have created a large number of Azarvari deposits, have been associated with the frequent rise of Andesite and Dacite magmas, successive eruptions, the formation of lava domes and the collapse of domes, and sometimes the release of lava. The effects of these events can be seen in near and medium facies. After this, the Sahand caldera collapses, and the next phase involves simultaneous eruptions after the formation of the caldera, accompanied by the creation of the last Azeri deposits and lavas. The effects of this phase can be seen in the central, near, and middle facies. Sahandchr('39')s central facade is located on the site of Caldera, and after the cessation of Magmayichr('39')s activities, it has undergone extensive heat transfer and severe erosion. Thermal alteration has had the greatest effect on the semi-volcanic infiltration mass, causing it to undergo completely alterations and a set of secondary minerals.

    Keywords: Sahand, Stratovolcano, Volcanic Facies, Pyroclastic deposits, Stratification
  • Fereidon Ghadimi*, Mahmoud Mirzaei Pages 560-579
    Introduction

    It produced millions of tons of solid waste annually during Iranchr('39')s household, mineral, agricultural, and industrial activities that are heavy metal-rich. Solid waste generation is the most important environmental and health problem in the world, especially in developing societies. The rapid growth of urban, agricultural, and industrial activities, along with population growth, produces a wealth of waste. Open landfills are the oldest and most abundant solid waste landfill in the world. Uncontrolled landfills can have an adverse effect on the environment and human health. The most important risk of landfill on human health is sediment contamination by waste leachate. Municipal waste landfills can be associated with the release of contaminants due to leachate infiltration into sediments and surface and groundwater of the surrounding environment. The purpose of the present study was to determine the heavy metals contaminants of Arak landfill in comparison with the upper crust reference, to evaluate landfill pollutant indices at different depths, to determine the sources of Arak landfill and to determine the role of Arak landfill in the production of all types of heavy metals.  

    Materials and methods

    Arak landfill is located in Amanabad plain and upstream of 14 drinking water wells in the Arak city. Annually, 350 tons of Arakchr('39')s garbage is brought to the landfill, 30% of which is dry waste (paper, glass, metals) and the rest more waste (kitchen waste, food, fruits).Thirty one sediment samples were collected from three boreholes in Arak landfill in 1396 (borehole with 22.5 m depth, 13 samples, borehole with 17.5 m depth, 10 samples and borehole with 13 m depth, 8 samples). It was determined texture, physical and chemical composition and heavy metals(Pb, Cr, Ni, Cu, Zn, As and Hg) of the sediments.  

    Results and discussion

    The mean concentrations of Pb, Ni, Cu, Zn, As and Hg were 32, 64, 25, 73, 15 and 6.90 mg / kg in Arak landfill sediments, respectively, and greater from their mean concentrations in the upper crust (17, 18,13, 47, 5 and 0.05 mg / kg). The average concentration of Cr (39 mg / kg) is lower than the mean concentration in the crust (92 mg / kg). The enrichment coefficients of Pb, Cr, Ni, Cu and Zn vary from low to medium, for As from low to very high, and extremely high for Hg. The geo-accumulation coefficient is low for all elements except for Hg. The geo-accumulation coefficient is medium for Hg. Evaluation of the concentrations of Pb, Cr,Ni, Cu, Zn, As in three boreholes showed that their concentration did not show a specific trend towards depth. The enrichment coefficient and geo-accumulation coefficient for Pb, Cr,Ni, Cu, Zn, As were also absent trend. There is a great concentration of elements in specific  zones in depths. The amount of Hg as well as the enrichment coefficient and its geo-accumulation coefficient increase with increasing depth. In general, the degree of contamination of all elements increases with the depth in boreholes. In factor analysis, Cu, Mn, Ni, Zn and Pb were positively correlated in one group. As, Hg and organic matter are in another group. The correlation of As with Hg and organic matter is reversed. Also, the variables of mud, sand and gravel were in the other group, in which gravels were inversely correlated with mud and sand. The study showed that heavy metal concentrations of Cu, Ni, Zn and Pb occurred in an environment with high Mn. It was also enriched Hg in organic matter environments. In contrast, arsenic enrichment is in a separate phase that has no relation to organic matter. In addition, it was found that sediment texture (mud, sand and gravel) did not play a role in the concentration of heavy metals in surface and deep sediment of Arak landfill.

    Conclusion

    The analysis of dry and wet waste in long-term landfill accumulation in direct contact with precipitation and the runoff has involved the decomposition of heavy metals into deep sediment. Organic matter and manganese compounds play the most important role in the distribution of heavy metals at different depths in the sediments. Therefore, monitoring heavy metals in landfill leachate and downstream drinking water wells is essential. Since landfill is old and not engineering landfills, therefore, new landfills must be designed on the principles of landfill engineering. In addition, hydrological removal can prevent water from being exposed to landfill

    Keywords: Heavy metals, Soil pollution indices, Factor analysis, Arak landfill