فهرست مطالب

  • پیاپی 25 (بهار 1400)
  • تاریخ انتشار: 1401/03/11
  • تعداد عناوین: 8
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  • هما رستمی، قاسم عزیزی*، حجت دارابی، مهران مقصودی، سحر ملکی، جواد درویشی خاتونی صفحات 611-628

    پژوهش حاضر با هدف شناسایی و ارایه اطلاعات دقیق از رخدادهای خشک اقلیمی هولوسن میانی و پسین در زاگرس مرکزی انجام شده است. بررسی داده های حاصل از آنالیزهای ژیوشیمی، سن سنجی و حساسیت مغناطیسی بر روی 220 سانتی متر مغزه رسوبی برداشت شده از تالاب هشیلان، امکان بازسازی شرایط اقلیمی 6000 سال گذشته در منطقه زاگرس میانی را فراهم نمود. نتایج این مطالعات نشان دهنده افزایش طوفان های گرد و غبار در دوره های خشک بود که در دوره های زمانی 5200-5400، 4700-4850، 3700-4200، 3250-3400، 2100-2300 و 1500-1700سال قبل در منطقه رخ داده اند. بیشترین نوسانات و رخدادهای اقلیمی کوتاه مدت در منطقه متعلق به هولوسن پسین بوده است. همچنین نتایج آنالیزهای ژیوشیمی ، پذیرفتاری مغناطیسی و جرم کاهی گرمایشی، بررسی تغییرات عناصر و نسبت های عنصری رسوبات محیط تالاب نشان دهنده مطابقت رخدادهای خشک به همراه طوفان های گردوغبار با رخدادهای سرد هولوسن در نیمکره شمالی بود.

    کلیدواژگان: رخداد خشک اقلیمی، زاگرس میانی، مغزه رسوبی، تالاب هشیلان
  • سحر صادقی، محمد یزدی*، ایرج رسا، محمدرضا جانثاری صفحات 628-648

    با هدف ارزیابی منشا کانی های سنگین رسوبات کواترنر ، ابتدا واحدهای سنگ شناسی زورایان، با استفاده از سنجش از دور و نقشه های زمین شناسی تفکیک شدند. به منظور مطالعات پتروگرافی 60 نمونه از رخنمون های سنگی برای تهیه مقاطع نازک و برای بررسی تغعییرات عناصر اصلی، فرعی، کمیاب و طلا، 120 نمونه به روش Fire-Assay و ICP-OES و 8 نمونه ICP-MS انتخاب گردید. برای مطالعات دورسنجی تصاویر ASTER محدوده ، توسط نرم افزار ENVI مورد بررسی قرار گرفتند. نتایج نشان داد نهشته های پلاسری کواترنری محدوده زواریان دارای کانی های سنگین هماتیت، ماگنتیت، پیریت، کالکوپیریت و گالن می باشند. بر اساس شواهد صحرایی، مطالعات سنگ شناسی و سنجش از دور، کانی زایی طلا در سنگ های میزبان آندزیت و آندزیت بازالت همراه با رگه های کوارتز حفره دار و دگرسانی آرژیلیکی پیشرفته و آلونیتی شدن و به صورت رگچه های سیلیسی-اکسید آهنی صورت گرفته است. تجزیه نمونه های کان سنگ نشان می دهد که عیار میانگین عنصر طلا  ppm1.98 ، عیار میانگین عنصر مس ppm1236 و عیار میانگین عنصر آهنppm 175707.9 می باشد. نتایج مطالعات دورسنجی و ژیوشیمی نشان می دهد منشا کانی های سنگین موجود در نهشته های پلاسری کواترنری محدوده زواریان سازندهای آندزیتی و پیروکلاستیک میوسن و پلیوسن می باشند. بر اساس مطالعه صورت گرفته مطالعات ژیوشیمی و دورسنجی با هم تطابق داشته و در فاز اکتشافی برای ذخایر فلزی به خوبی تکمیل کننده هم می باشند.

    کلیدواژگان: پلاسر، کواترنری، کانی سازی طلا، زواریان، مرکز ایران
  • امیرسعید حسینی، سعید حکیمی آسیابر*، مژگان صلواتی صفحات 649-668

    رودخانه ها از مهمترین منابع آبی بوده و بررسی کیفیت آب آن ها بسیار حیاتی می باشد. از این رو در این مطالعه از 15 ایستگاه آبراهه های دایمی پیربادوش و گشون رودخانه قلیان استان لرستان که در مسیر شیل های نفتی قرار دارند، نمونه برداری صورت گرفت.  با آنالیز نمونه ها در آزمایشگاه، پارامترهای هیدروژیوشیمیایی محاسبه شدند و سپس مقایسه با استانداردها و رسم نمودارهای هیدروژیوشیمیایی جهت بررسی کیفیت آب شرب منطقه انجام شد. نتایج نشان داد، آب رودخانه قلیان حاوی کربنات کلسیم فراوانی است (به جزء نمونه P3 که مقدار بیشتری کربنات منیزیم دارد) که به دلیل دارا بودن کلسیم بالا برای نوشیدن نامناسب، ولی بر اساس سایر پارامترها مناسب است. بر اساس طبقه بندی کیفی شولر، نمونه های گشون کیفیت پایین تری نسبت به پیربادوش دارند و طبق استانداردها، اکثر نمونه ها در حد مجاز-مطلوب می باشند. براساس نمودارهای هیدروژیوشیمیایی، کیفیت آب آبراهه پیربادوش بهتر از گشون است و بر اساس نمودار گیبس، سنگ های بستر و هوازدگی و انحلال از عوامل اصلی کنترل کننده شیمی آب منطقه هستند.  در این منطقه نوع واحدهای سنگی و حتی وجود شیل های نفتی تاثیر مخربی بر کیفیت آب شرب منطقه نداشته است.

    کلیدواژگان: آب شرب، رودخانه قلیان، قالیکوه، شیلهای نفتی، نمودارهای هیدروژئوشیمیایی
  • معصومه خاکستری، سادات فیض نیا*، سید محسن آل علی، مصطفی ده پهلوان صفحات 669-694

    رودخانه حاجی عرب  یک رودخانه فصلی در جنوب استان قزوین است. این مطالعه جهت بررسی رسوبات این رودخانه و تعیین رخساره های رسوبی آن صورت گرفته است. از چهار گمانه و با بیشینه عمق 8.3 متری تعداد 57 نمونه از اطراف تپه باستانی قره تپه برداشت شده است. دانه بندی رسوبات به روش های الک خشک، الک تر و الک شیکر لیزری انجام شده است. بررسی رسوبات این رودخانه به شناسایی سه دسته رخساره رسوبی  منجر شد که عبارتند از: رخساره های گلی (Fl ,Fm ,Fr) ، ماسه ای (Sm ,Sp ,Sl ,Sh) و گراولی (Gh ,Gcm ,Gms ,Gci ,Gmg  ,Gmm)، که در قسمت های مختلف محیط رودخانه ای ته نشست کرده اند. براساس رخساره های شناسایی شده، عناصر ساختاری خارج کانال (FF)، ماسه با اشکال لایه ای (SB)، بار گراولی و اشکال لایه ای (GB)، جریان گراویته ای (SG) و کانال (CH) در این حوضه رسوبی شکل گرفته اند. مدل های رسوبی این رودخانه شامل رودخانه های مآندری با بار ریزدانه، مآندری با بار ماسه ای، بریده بریده با بسترگراولی و بریده بریده گراولی کم عمق می باشد.

    کلیدواژگان: دشت قزوین، رودخانه حاجی عرب، قره تپه سگزآباد، محیط رسوبی، مدل رسوبی
  • نفیسه حاج نوروزی، محسن پورکرمانی*، مهران آرین، زهرا ملکی، علی سلگی صفحات 696-713

    گستره مورد پژوهش (ناحیه گلپایگان) در زون ساختاری سنندج - سیرجان قرار گرفته است که یکی از پویاترین پهنه های  لرزه زمین ساختی ایران است. در این بررسی، یک مدل نظری برای ارزیابی پتانسیل حرکتی گسل بر اساس رابطه بین ویژگی های هندسی گسل و میدان تنش تکتونیکی ناحیه ای پیشنهاد شده است. لازم به ذکر است که نتایج این روش با رکورد های لرزه ای گذشته و فعالیت های ریز لرزه ای کنونی منطقه سازگار بوده است، لذا این الگوی نظری بر مبنای روابط میان ویژگی های هندسی گسل ها و میدان تنش زمین ساختی ناحیه ای استوار است.  داده های ساختاری به منظور دستیابی به موقعیت محور های اصلی تنش، در پهنه وسیعی از ناحیه مورد مطالعه برداشت گردید که از معادلات این الگو در 6 ایستگاه منطقه مذکور استفاده شد. در نهایت، با استفاده از روش وارون سازی، تنش اصلی بیشینه در هر مقطع به طور جداگانه به دست آمد و در معادلات جاگذاری شد. طبق محاسبات، پتانسیل حرکتی گسل در هر مقطع از گسل های ناحیه مشخص گردید،  گسل بید عرب بیشترین پتانسیل حرکتی در مقایسه با دیگر قطعات گسلی را دارا است که با توجه به محاسبه شاخص پیچ و خم پیشانی کوهستان به خوبی نمایان می شود که در رده یک تکتونیکی با فعالیت بالا جای دارد، دیگر گسل ها در مرحله پیش لرزه می باشند. نتایج محاسبه پتانسیل حرکت گسل ها در هر قطعه، تطابق خوبی را با فراوانی زمین لرزه های رخ داده نمایان می سازد، به طوری که بخش خاوری ناحیه مورد مطالعه، دارای نرخ لرزه خیزی بیشتری نسبت به دیگر بخش های آن می باشد. با توجه به سرعت متوسط لغزش گسل های ناحیه در سال های اخیر و همچنین با توجه به مطالعات پیشین و نتایج به دست آمده از ناحیه و داده های حاصل از محاسبه مقادیر پتانسیل حرکتی گسل، بخش خاوری ناحیه (حدفاصل گسل بید عرب تا گسل نر پلنگ) بیشترین میزان احتمال لغزش در آینده را دارا خواهد بود. بخش جنوبی گسل بید عرب، با بیشترین میزان پتانسیل حرکتی گسل همراه است و ساختارهای تکتونیکی نواحی آن، به عنوان جوان ترین فعالیت های نیوتکتونیکی در ناحیه معرفی می گردد.

    کلیدواژگان: گسل های جنبا، توان حرکتی، تنش اصلی بیشینه، میدان تنش زمین ساختی ناحیه ای
  • لیلی ایزدی کیان*، غلامرضا خدادادی صفحات 714-730

    گنبد نمکی کوهرنگ  در  شمال غرب استان  چهارمحال و بختیاری و در زیر پهنه ساختاری زاگرس مرتفع قرار دارد. این گنبد نمکی در کوهپایه ارتفاعات زردکوه (زرده) و تحت تاثیرفعالیت گسل های کوهرنگ ، دهنو، زردکوه و گسل های عرضی (فرعی) بین گسل های کوهرنگ و زردکوه قرار دارد. توالی های رسوبی ستبر زاگرس سنگ هایی با سن اینفراکامبرین تا عهد حاضر را در بر می گیرد. هدف از این پژوهش ارزیابی فعالیت نوزمین ساختی منطقه با استفاده از شاخص های ژیومورفیک شامل انتگرال هیپستومتری (Hi)، شاخص عدم تقارن حوضه زهکشی (Af) ، شاخص گرادیان رودخانه (SL)، شاخص سینوسیته جبهه کوهستان (Smf)، شاخص نسبت پهنای دره به عمق دره Vfو شاخص زمین ساخت نسبی  (Iat) می باشد. براساس نتایج بدست آمده بیشترین فعالیت نو زمین ساختی مربوط به قله های زردکوه، کلونچین و دره خدنگ بوده و در قسمت های گنبد نمکی کوهرنگ و شهر کوهرنگ و زمین های کشاورزی اطراف گنبد نمکی ، فعالیت کم تا متوسط می باشند. با توجه به مقاومت پایین واحدهای گنبد نمکی، اغلب شاخص های ژیومورفیک برای حوضه های مجاور آن مقدار پایین را نشان می دهند ولی  شاخص عدم تقارن حوضه بخاطر برخاستگی گنبد نمکی فعالیت آن را بهتر از شاخص های دیگر نشان می دهد.

    کلیدواژگان: شاخص های ژئومورفیک، زمین ساخت جنبا، گنبد نمکی کوهرنگ، زاگرس مرتفع
  • علی سیستانی پور* صفحات 730-742

    سامانه گسلی بافق-باغین یکی از گسل های مهم ایران مرکزی است و به موازات گسل کوهبنان در شمال خاوری و گسل رفسنجان در جنوب باختری امتداد یافته است. منطقه مورد مطالعه در حوزه ایران مرکزی و بخش جنوب خاوری آن واقع شده است. در آخرین تقسیم بندی ایران مرکزی این منطقه در بلوک پشت بادام قرار می گیرد. در این تحقیق، با استفاده از تصاویر ماهواره ای و نرم افزارهای مربوطه و تلفیق با داده های صحرایی،  قطعات سامانه گسلی شناسایی و ترسیم گردید. همچنین از روابط و فرمول های مورفوتکتونیکی برای تحلیل ریخت زمین ساختی منطقه استفاده شد . با پردازش تصاویر ماهواره ای منطقه و بر اساس مطالعه پارامترهای ساختمانی، وضعیت هندسی، تعقیب امتداد سامانه گسلی، بررسی تغییرات در امتداد، جهت حرکت و ساختارهای فرعی انشعابی در طول سامانه، مشخص گردید که سامانه گسلی راستالغز بافق-باغین نیز مانند اغلب گسل های فعال به صورت قطعه های جدا از هم شکل گرفته است. در یکی از حوضه های جدایشی-کششی منطقه، روستایی حاصلخیز به نام خنامان در جبهه جنوب باختری سامانه گسلی بافق- باغین شکل گرفته است.

    کلیدواژگان: سامانه گسلی، بافق باغین، ریخت زمین ساخت، راستالغز راستگرد
  • افسانه دهقان چناری، سادات فیض نیا*، سید محسن آل علی، منوچهر قرشی صفحات 743-771

    دریای خزر بزرگ‌ترین توده آبی محصور در خشکی است که از حدود سه‌میلیون سال پیش از دریاهای جهان جدا شد. مغزه‏های مورد مطالعه در بخش‏های شرقی بابلسر، شمال شرقی جویبار، و شرق زاغمرز در سواحل جنوبی دریای خزر واقع شده است. این پژوهش با هدف تفکیک و بررسی رخساره‏ها و محیط رسوبی و نیز ژیوشیمی عناصر با مطالعه مغزه‏های رسوبی انجام شد. طی بررسی‏های میدانی سه مغزه BAG و AZD و AM با تناوبی از رسوبات آواری ریز تا متوسط دانه به ترتیب با عمق‏های تقریبی 700 و 500 و 900 سانتی‏متری انتخاب شدند. در مجموع 92 نمونه برای مطالعات رسوب‏شناسی (46 نمونه) و ژیوشیمی (46 نمونه) مورد تجزیه‌وتحلیل قرار گرفتند. دانه‏بندی رسوبات درشت و ریز دانه به ترتیب با الک مرطوب و لیزری صورت پذیرفت. تحلیل ژیوشیمی عناصر اصلی و فرعی رسوبات نیز با استفاده از ICP-OES انجام شد. بر اساس مطالعات رسوب‏شناسی و بافتی، رخساره‏های گل ماسه‏ای قهوه‏ای، ماسه‏ای تا ماسه‏گلی خاکستری، و گلی تا رس سیلتی ماسه‏ای سیاه شناسایی شدند. در توالی مغزه‏ای نسبت‏های عنصری Ti/Al و Fe/Al در افق‏های رسوبی دانه‏ریز و Si/Al و Zr/Al در افق‏های رسوبی دانه‌درشت هماهنگی و انطباق خوبی نشان می‏دهند که به ترتیب حاکی از کاهش و افزایش انرژی محیطی است. همچنین انطباق قوی بین Ca و Sr در برخی افق‏های مغزه‏ها حاکی از رسوب‌گذاری کانی‏های کربناته در درون دریا یا دریاچه به صورت زیستی است.

    کلیدواژگان: محیط رسوبی، ژئوشیمی، رخساره های رسوبی، تغییرات سطح آب دریا، دریای خزر
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  • Homa Rostami, Ghasem Azizi*, Hojjat Darabi, Mehran Maghsoudi, Sahar Maleki, Javad Darvishi Khatooni Pages 611-628

    Climate, as the average temperature or precipitation over a long period of time, is constantly fluctuating and changing. There is a complex relationship between climate change and human biological and cultural reactions (Weeks and Petrie, 2018). Increased dry conditions in the subtropics is one of the consequences of climate change that has been predicted by various models. While using the results of various paleo climate archives can reconstruct the climatic conditions of the past several thousand years and provide more accurate forecasts for the future. Due to the fact that the physical and chemical properties of sediments have an extraordinary power in recording climatic and environmental events with high sensitivity, so the use of sedimentary geochemical results in identifying and reconstructing the effects of dry climatic events is one of the most common method (Sai, 2004).

    Material and method

    In order to identify and reconstruct the Middle and Late Holocene dry events, a 2-meter sediment core was used from the middle part of Heshilan marshland. The coring was performed using a Russian coroner. In this study, 5 samples were analyzed by radiocarbon method (C14-AMS) at the Institute of Physics and Astronomy, University of Aarhus, Denmark. Magnetic susceptibility measurements of the samples and measurements were performed using a COX Itrax CS37 scanner at the Bartington MS2C magnetometer at the Geogenetics Laboratory of the Copenhagen Geological Museum in Denmark. The magnetic susceptibility of the samples was measured with an accuracy of 5 mm and the Itrax analysis with an accuracy of 1 mm.

    Results

    The study of climatic events of the last six thousand years showed the fluctuation of climate between cold, dry and warm phases in the study area, which was consistent with the climatic events of the northern hemisphere. The results showed that dust storms occurred in the period of 5400-5200, 4850-4700, 4200-3700, 3400- 3250, 2300-2100 and 1700-1500 years ago in the region. The length of the region's dry climatic periods has often been 200 years. The longest dry period identified in the region dates back to 4200-3700 years ago.

    Keywords: Dry climatic event, Central Zagros, Sedimentary core, Hashilan marshland
  • Sahar Sadeghi, Mohammad Yazdi*, Iraj Rasa, MohammadReza Janesari Pages 628-648
    Introduction

    Epithermal deposits are usually found in association with near-surface magmatic-hydrothermal environments with volcanic rocks. According to studies, their formation depth is less than 1.5 km and the temperature for their formation is less than 300 ° C. Epithermal deposits are usually rich in gold to gold-silver and rich in silver and include low sulfide, medium sulfide and high sulfide types. One of the anomalous areas for mineralization of epithermal type gold is located in the area of Zavarian in Qom, central Iran. The following article is about some results of our research about origin of Quaternery placer in the area of Zavarian.

    Materials & Methods

    The collected samples were chosen from samples which are associated with mineralization and host rock for geochemical studies. Samples were selected after field and petrographic studies. ICP-OES and Fired-Assay analize measurements were made on 120 samples and ICP-MS analize were made on 8 samples. Aster images were analized with ENVI for remotesinsing study.

    Results and Disccusions

    Petrographic studies show that the basement rocks of the area include volcanic units of Miocene- Pliocene (MPb), volcanic andesite units of Miocene- Pliocene (MPan), volcanic- pyroclastic units of Miocene- Pliocene (MPVP), pyroclastic units of Miocene- Pliocene and recent alluvium. The plutonic rocks of the area are granodiorite-tonalite. The intruded dykes are subdivided to andesite dykes (DY1) and dacite dyke (DY2). The main alterations are advanced argillic, alunitization, propylitic, sericitic and silicification. Gold mineralization has been occurred in andesite and dacite dykes. Au-mineralization are mostly vein, breccia and replacement type. Ore minerals include magnetite, hematite, Fe-hydro-oxides, chalcopyrite, purite and bornite which are host of Au. The results of remote sensing and geochemical investigation suggest that the origin of hematite, magnetite, Purite, chalcopyrite and galena are volcanic- pyroclastic units of Miocene- Pliocene in quaternary placers. The results of ICP-OES and ICP-MS show that the average grade of gold in the study area is 1.36 ppm, which is 194 times richer than the average of earth crust (0.007 ppm). The maximum gold grade in the mineralization zone is 10.76 ppm. The average grade of silver is 2.69 ppm, which is 44.8 times richer than the average of earth crust (0.06 ppm). The average grade of copper is 1236 ppm and it is 40.19 times richer than the average of earth crust (30 ppm). The average grade of iron is 175707.9 ppm and it is 3.51 times richer than the average of earth crust.

    Conclusions

    Zavarian gold deposit is located 60 km SW of Qom and in Central Iran geotectonic zone. Gold mineralization has been occurred in andesite and dacite dykes which are associated with advanced argillic, alunitization, propylitic, sericitic and silicification. Au-mineralization are mostly vein, breccia and replacement type. Ore minerals include magnetite, hematite, Fe-hydro-oxides, chalcopyrite, purite and bornite which are host of Au. Geochemical data show that the average content of Au is 1.98ppm. Mineralogical, geochemical, alteration data show that gold mineralization in the area is epithermal high sulfide type. Also, the presence of chalcopyrite, bornite, Au-Cu-As- Ag- Pb, advanced argillic-alunitization, vague quartz texture, vein-veinlet-breccia and replacmente mineralization type support this idea too. The results of remote sensing and geochemical investigation suggest that the origin of hematite, magnetite, Purite, chalcopyrite and galena are volcanic- pyroclastic units of Miocene- Pliocene in quaternary placers.

    Keywords: Placer, Quaternary Epithermal type, Zavarian, Central Iran
  • Amirsaeid Hosseini, Saeid Hakimi Asiaber*, Mojgan Salavati Pages 649-668
    Introduction

    Rivers are one of the most important water resources and it is very important to study their water quality. Therefore, in this study, sampling was done from 15 permanent waterway stations of Pirbadush and Gashun of Qolyan River in Lorestan province, which are located in the path of oil shales.

    Materials and Methods

     Hydro-geochemical parameters were calculated by analyzing the samples in the laboratory. Then compared with drinking water quality assessment standards in the region and Hydro-geochemical diagrams were also drawn.

    Discussion and Results

    Qolyan River water contains a lot of calcium carbonate and only sample P3 has more magnesium carbonate that it is unsuitable for drinking due to its high calcium content, but it is suitable based on other parameters.

    Results

    According to Schoeller quality classification, Gashun samples are of lower quality than Pirbadush and by the standards, most samples are within the allowable-favorable range and water of G6, G7, P5 stations have lower quality than other stations. According to the WHO table, the water of the Qolyan River is relatively light in terms of TH and total dissolved solids (TDS) and relatively light in terms of Electrical conductivity (Ec). Based on hydro-chemical tests and data analysis and hardness estimation and comparison with the national standard of Iran and the standard of the World Health Organization, the results of water classification of the samples are as follows: According to the World Health Organization's calcium ion (Ca2 +) content, water samples from G7 and P5 stations are impermissible and based on the total hardness of the Iranian national standard, the water samples of stations P1 and P3 are in the favorable level.According to hydro-geochemical diagrams, the water quality of Pirbadush waterway is better than Gashun. According to the Piper diagram, In Gashun samples, the tendency of the samples towards magnesium and sulfatation is more than the samples of Pirbadush region. According to the Durov diagram, most of the water samples taken from Gashun and Pirbadush waterways are calcium carbonate (Ca-CO3) and calcium bicarbonate (Ca-HCO3). According to Schoeller diagram, the amount of tumble in the samples of Gashun waterway is more than Pirbadush waterway. According to the ion equilibrium diagram, the amplitude of change of anions and cations in Gashun waterway is more than Pirbadush. According to Stiff diagram, the different origins of the samples indicate the existence of several bedrock sources for the samples, and according to the Gibbs diagram, bedrock and weathering and dissolution are the main factors controlling the water chemistry of the region.By examining the water quality of Qolyan River in Pirbadush and Gashun waterways with any human activity that it is in the path of oil shales, the results were obtained which are:-The highest amount of cations and carbonate anion (CO32-), is in G7 station andthe highest amount of nitrate anion (NO3-), are in G6 and P7 stations.-The highest water total hardness (TH) is related to stations G7, G6, P5 and the lowest is related to stations P3, P1, G1.-The highest total dissolved solids (TDS) in water is related to stations G6, G5,  G7 and the lowest amount is related to P1, P4, P3.- The presence of higher amount of calcium carbonate (Ca-HCO3) in Gashun waterway than Pirbadush indicates a higher degree of solubility of calc than dolomite in this section.- High sulfate content in Gashun waterway (especially G1 station) can be related with further dissolution of anhydrites in the Gotnia Formation.-Anion and cation equilibrium also shows that ionic equilibrium is present only at stations G3, G5, P6. However, at stations P1 and P3, there is a high degree of ionic imbalance between anions and cations.
     

    Conclusion

     In this area, the type of rock units and even the presence of oil shales have not had a detrimental effect on the quality of drinking water.

    Keywords: Drinking water, Qolyan River, Qalikuh, Oil shales, Hydro-geochemical diagrams
  • Masoume Khakestari, Sadat Feiznia*, Seyed Mohsen Aleali, Mostafa Dehpahlavan Pages 669-694
    Introduction

    Haji-Arab River is a seasonal river in the south of Qazvin province. Quaternary alluvial deposits in Qazvin province spread on wide range. Since many coherent studies in terms of geology, sedimentary environment, mineralogy and climatic conditions have not been done in the mentioned sediments, so this study has been done to study the sediments of this river and determine its sedimentary facies. Therefore, the results of this study can provide a more precise understanding of the sedimentology status and sedimentary environment of this area.

    Materials and methods

    This study was conducted to investigate the sediments of this river and to determine its sedimentary facies. Sampling was done from 4 boreholes and trenches around the ancient Qara Tappeh hill. Sediment granulation has been done by dry sieving, wet sieving and laser shaker sieving. Sedimentological studies show that the occurrence of frequent floods in the region has changed the texture of channel sediments and changed various parameters of particle size. Haji-Arab River, flows from south to north direction. This river originates from the central mountains and extends to Sagz-Abad. Sampling has been done around the ancient hill of Sagz-Abad (Qara-Tappeh) with an altitude of 1274.9m above sea level. This hill is located 52 km south of Qazvin (7 km north of Sagz-abad of environs Buin-Zahra city) and 132 km west of Tehran. Sampling were done in September 2016. The boreholes and trenches were excavated by Department of Archaeology, University of Tehran. From 4 boreholes with a maximum depth of 8.3 meters, 57 samples have been taken from around the ancient hill of Qara-Tappeh. Collected samples were dried due to humidity outdoors. 15% of the samples were granulated in two forms: dry and wet. Since the result difference was more than 10% due to grains adhesion, other samples were sieved by wet method. Particles smaller than 4µm were granulated by laser shaker sieving. Statistical parameters such as kurtosis, sorting, skewness and mean were calculated using Gradistat software. Also In this study, sedimentary facies were studied using field and laboratory methods. Sediment type was named based on Folk (1974) classification and facies classification based on Miall classification (1996, 2006). Finally, by combining all the data, a sedimentary model for Haji-Arab River was offered.

    Results

    The study of sediments in this river led to the identification of three categories of sedimentary facies, which are: mud facies (Fl, Fm, Fr), sandy facies (Sm, Sp, Sl, Sh) and gravel (Gh, Gcm, Gms, Gci, Gmg, Gmm), which have settled in different parts of the river environment. Based on the identified facies, structural elements Floodplain Fines (FF), Sandy Bedforms (SB), gravelly Bars and Bedforms (GB), Sediment Gravity flow deposits (SG) and channels (CH) have been formed in this sedimentary basin. Sedimentary models of this river include Fine-Grained Meandering River, Sand-Bed Meandering River, Gravel-Bed Braided River and Shallow-Gravel-Bed Braided River.

    Conclusion

    Generally, coarse-grained, sandy and fine-grained sediments, poorly to very poorly sorting, absence of fossils, light color of sediments, the presence of plant traces indicate that the Quaternary sediments of the study area form in river system which include sub-environments such as, Channel, off-channel and floodplain deposits. Examination of sediment sequence in the study area shows the transition from a humid and low-energy environment to a dry and high-energy environment during the Quaternary. According to field studies and studies of sedimentary facies of Haji-Arab River, silt sediments are the most widespread in Haji-Arab catchment. Gravel with lower percentage are observed in limited parts of the basin and in the upper parts of the studied sequences. Therefore, based on the above evidence and the characteristics of facies in the Miall (1996) classification, fine-grained sediments have been deposited in the meandering River and coarse-grained sediments of this region have been deposited in a braided river. According to the studies, the architectural elements of FF, CH and SB and to a lesser extent GB and SG can be considered for this basin. Based on this, Can be considered 4 river models including fine-grained meandering rivers, Sandy meandering river, gravel wandering river and shallow gravel bed braided can be used for Haji-Arab River in the study area.

    Keywords: Qazvin plain, Haji-Arab River, Qara Tappeh Sagz-Abad, sedimentary environment, sedimentary model
  • Nafiseh Hajnorouzi, Mohsen Pourkermani*, Mehran Arian, Zahra Maleki, Ali Solgi Pages 696-713

    Study of area (Golpayegan area) is located in the Sanandaj-Sirjan structural zone, which is one of the most dynamic tectonic seismic zones in Iran. Among the most important faults of Janba in the study area, we can mention Khansar, Hila, Narpalang, Boland Ab, Qara No, Bid Arab faults. In this study, a theoretical model is proposed to evaluate the Fault Movement Potential based on the relationship between the geometric properties of the fault and the regional tectonic stress field. This model by et al. (1997) Lee, and has been used to evaluate the mobility potential of major faults in the Hong Kong area. This parameter allows for the percentage of possible movements in the current tectonic regime (CTR) for all active faults in a range. It should be noted that the results of this method are consistent with past seismic records and current micro-seismic activity in the region, so this theoretical model is based on the relationship between the geometric properties of faults and the regional tectonic stress field. To evaluate the mobility potential of active faults in Golpayegan area in the northwest of Kush to the southeast of Bid valley, the structural zone of Sanandaj-Sirjan.

    Methods

     Structural data were collected in a large area of ​​the study area in order to achieve the position of the main stress axes. The equations of this model were used in 6 stations in the mentioned area. Finally, using the inversion method, the maximum maximum stress in each section was obtained separately and placed in the equations.

    Conclusion

    According to the calculations, the motion potential of the fault in each section of the faults in the area was determined that the Arab willow fault has the highest movement potential compared to other fault parts, which according to the calculation of the mountain frontal maze index is well visible. Category 1 tectonics with high activity, other faults are in the pre-seismic stage. The results of calculating the potential of faults in each section show a good agreement with the frequency of earthquakes, so that the eastern part of the study area has a higher seismicity rate than other parts. Due to the average landslide velocity of faults in recent years and also according to previous studies and results obtained from the area and data from the calculation of fault potential values, the eastern part of the area (the distance between Arab willow fault and male leopard fault ) Has the highest probability of slipping in the future. The southern part of Bid Arab fault is associated with the highest mobility potential of the fault and the tectonic structures of its areas are introduced as the youngest neotectonic activities in the area.

    Keywords: Active Fault, Movement potential, Maximum mainly stress, Regional tectonic stress field
  • Pages 714-730
    Introduction

    Changes in land surface shape in active tectonic  zones result from interplay between tectonic forces and surface processes (Keller and Pinter, 1996; Keller et al., 1999). Salt Domes  are dome-shaped Geological structures whose central core is composed of salt. Their economic importance is due to the location of oil tanks in structures with salt domes and also the presence of sulfide sources of potash, iron and salt in them. Zagros region, in which Koohrang city is located, is a pressure zone where Koohrang fault is located in the southwest, Dehno fault is located in the east , Mohammadabad fault is located in the north of and Zardkuh fault is located in the south of salt dome. In the meantime, the salt dome has come to the surface with a lower density due to the movements of faults and stress from the Arabic plate to the Iranian plate. There are many linear springs in this area, which are faults and indicate the activity of faults in the area.

    Materials and methods

    In this study, in order to evaluate the new construction activity of the region, the location of Koohrang salt dome was determined, using Baba Haidar 1: 100000 maps, Shahrekord 1: 250,000 map.  Using the data of these maps as basic data in ArcGis software (10.3), drainage network and digital elevation model (DEM) of the study area were used as basic elevation data. Using the data of these maps as basic data in ArcGis software (10.3), and digital elevation model (DEM) of the region and ArcHydro toolbar, 98 basins were considered for the study area. Then, according to the characteristics of the region, drainage basin asymmetry index (Af), hypostometric integral index (Hi),stream length gradient index (SL), mountain front sinusitis index (Smf), valley to depth-to-depth ratio index (Vf), index Relative activity (Iat) was calculated for the study area and the results of each index are plotted. 

    Results and discussion

    In terms of basin asymmetry index, 36 basins are active in class 1 and in terms of tectonic activity, 38 basins are moderately active, 24 basins are in class 3 and have low tectonic activity. In terms of hypsometric integral index, 15 basins have new active tectonic activity (their height is higher than the average height of the study area, high areas with deep incisions), 17 basins are in class 2 and have medium activity and 66 basins have low tectonic activity. For the SL index, 19 basins in class 1 have high tectonic activity, 8 basins in class 2 have medium tectonic activity, 34 basins in class 3 have low tectonic activity and 37 of its basins have very little new tectonic activity, which are located near the main river. For the mountain frontal sinusitis index, 28 basins have high tectonic activity, 12 basins have medium tectonic activity, 7 basins have low tectonic activity and 51 basins have very low activity (data not obtained). The highest value of Smf index is 1.04 for basins 2, 13, 23 and the lowest value is 1.69 for basins that are in class 3 and yellow in the map . The lower the value of the index, the more active the tectonics of the region and the straight mountain fronts. In valley to depth-to-depth ratio index, a number of basins that cut off the mountain winding all include V-shaped and young valleys. In the general survey, 8 basins are very active, 16 basins are active, 54 basins have low tectonic activity and 20 basins have very low tectonic activity.

    Conclusion

    In this study, according to the measurement of stream length gradient index (SL) , drainage basin asymmetry index (Af), mountain sinusitis index (Smf), hypostometric integral index (Hi), valley width to depth ratio index (Vf), Relatively active tectonics index (IAT) has been used to study the relative active tectonics activity of the region. According to the zoning map obtained from the above indicators, the most activity in the study area is related to the basins that have active faults and high activity of the newest structure can be seen in the heights of Klonchin, Khadang Valley and Zardkooh. In this area, Koohrang salt dome and agricultural lands, Koohrang city and Dehno village have low to medium activity. The more we move from the Koohrang salt dome to the heights of Zardkooh, the more and more active the new tectonic activity of the region. Evidence from the diversion of streams, digging the bed of alluvial fans, V-shaped valleys and triangular shapes in the study area show high neotectonic activity This part (Zardkooh heights) of the study area.

    Keywords: Geomorphic indices, active tectonics, Koohrang salt dome, high Zagros
  • Ali Sistanipour* Pages 730-742

    The Bafq-Baghin fault system is one of the major faults in Central Iran and parallel to the Kuhbnan fault in the northeast and the Rafsanjan fault in the southwest. This fault system, under the influence of the stress, is the maximum that results from the convergence of the Arabian plate towards Iran plate has a right-strike with a compression component.  The study area is located in central Iran and its southeastern part. In the last division of central Iran, this region is located in the Poshtbdam.

    Methods

     Using satellite images and related software and integration with field data, fault system components were identified and mapped. Morphotectonic relationships and formulas were used to analyze the tectonic morphology of the region. Active strike-slip faults, especially those on the mountain front, usually appear as separate sections. By processing satellite images of the region and based on the study of building parameters, geometric condition, tracking along the fault system, examining changes along the direction, motion and branching sub-structures along the system, it was determined that the Bafgh-Baghin fault-slip fault system is like most active faults. It is formed in separate pieces.

    Results and conclusion

      By studies performed during the system, 60 fault pieces were identified. Bafgh-Baghin fault sections were examined for tectonic morphology, which is evidence that the Bafgh-Baghin fault system is adjacent. In the direction of fault sections, fault precipices have been formed, which in some cases, several-meter precipices were observed. Folds with strike-slip faults are usually stepped and sloping to the main cutting direction. The term en echelon refers to the arrangement of buildings in a linear zone, so that the folds or faults are parallel to each other and have the same tendency towards the direction of the linear zone. The naming of en echelon folds is based on the displacement of the right-slip zones that create them, so that right-slip faults create right-handed folds and left-handed right-slip faults create left-handed folds. Due to the right-slip activity of fault sections, some folds in the mountains have become right-stepped. Large amounts of Vf are associated with low uplift rates, ie low tectonic activity, in which rivers have relatively wide bottoms. Low Vf values refer to deep valleys in which rivers actively dig valleys and are usually associated with active tectonics and uplift.Mountainous fronts associated with active tectonics have sinusoids (Smf) between 1.6 and 1. Low-activity mountain fronts have sinusoids between 3 and 1.6, and inactive mountain fronts have sinusoids of about 3 to values greater than 5 because of high erosion and inactive tectonics. The low values of mountain front page maze (Smf) and the ratio of valley width to valley depth (Vf) calculated in the direction of fault plots indicate fault and tectonic faults of the region. Wherever the strike-slip fault becomes stepped or bends, due to the movement of the fault in these areas, it either suffers from divergence and tensile forces that lead to elongation and pull-apart basin, or suffers from convergence forces that result. They create compression and pressure in the basin. In the pull-apart basin, normal faults and subsidence are created and it is a suitable place for sediment accumulation. In the compressive basin, compressive ridges and inverse faults are formed. Due to the fact that Bafgh-Baghin fault sections have a strike-slip mechanism, where the pieces are placed relative to each other, pull-apart basins and compressive basins are formed between these fault sections. With the strike-slip activity of the fault sections, pull-apart basins have been created between some fault sections that are staggered relative to each other. In one of the pull-apart basins of the region, a fertile village called Khanaman has been formed on the southwestern front of the Bafgh-Baghin fault system.

    Keywords: Fault System, Bafq-Baghin, morphotectonic, right-strike slip
  • Pages 743-771
    Introduction

    The sediment cores BAG, AZD and AM in the Babolsar, Jouybar and Zaghmarz areas are located at the southern Iranian part of the coastal plain of the Caspian Sea. These areas are contained by major mountain ridge, the Alborz in the south (Central Alborz Structural Zone). The Alborz Mountain represent the main source of terrigenous materials in the South basin of the Caspian Sea. The geology of the southern part of the Caspian Sea catchment include sedimentary deposits, loess and terrasses, volcanic rocks, Precambrian metamorphics and Jurassic massive limestones (Aghanabati 2004; Lahijani and Tavakoli 2012).Sedimentary facies are controlled by physical processes such as velocity, depth and type of flow and sediment transport rates (Catuneanu 2006). Sediments are deposited in various depositional environments based on physical, chemical, and biological processes (Fursich, 1995; Walker, 2006). This study focuses on the interpretation of sedimentary facies, sedimentary environment and geochemistry of the sediments from the core successions. The results of this study can be useful in the palaeoenvironmental reconstruction in the southern Iranian part of the coastal plain of the Caspian Sea through the Quaternary time.

    Materials and methods

    Detailed field investigations were carried out on the three core sediments from the Babolsar, Jouybar and Zaghmarz areas. Using the rotary drilling machine, cores BAG, AZD and AM were obtained during 2016 fieldworks. A total of 88 representative samples were collected from three cores at different depths for the sedimentological (46 samples) and whole rock geochemical (42 samples) analyses. After collection, selected samples were sealed in polyethylene bags and then air-dried in the laboratory. The granulometric characteristics and textural properties were determined using Sieve analysis. Then, 46 samples were classified following Folk’s (1974). Subsequently, the 42 samples were powdered to less than 200 mesh using an agate mortar. The selected major and trace elements concentrations were measured using an Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) at the Geological Survey and Mineral Exploration, Tehran, Iran.

    Results and discussion

    Based on the sedimentological characteristics, cores BAG, AZD and AM have been divided into three lithofacies. They include sandy mud, muddy and sandy to silty sand lithofacies. Sandy mud lithofacies is characterized by pale-yellow to light-brown (partly mottled), poor sorting with a maximum thickness. This facies is also dominated by massive to rarely thin lamination, abundant plant fragments and roots, individual shell fragments, and lack of marine fossils. The presence of plant roots and pale-yellow to light-brown colour and massive to thin lamination claystone facies indicate suspension fallout from standing water in floodplain setting (Selim 2017). Sandy/ silty sand lithofacies is supported by the presence of unconsolidated lightly gray silty sand, moderate to well sorting, with high bivalve contents and the deposition of alternating layers of silt and fine to coarse sand. This lithofacies has an unclear and irregular boundary with the underlying facies and has up to 1 m thickness. Coarse-grained texture with moderate to well sorted particles indicate deposition under high-energy conditions in a beach setting (Sim and Lee, 2006)Muddy facies consists of poorly sorted, alternative horizons of light green to dark grey-coloured silty clay, with the thickness varies from 0.5 to 2 m. In this lithofacies, foraminifera and ostracod shells, endogenic gypsum mineral as well as calcite were also observed. The fine-grained texture, dark gray to black colored and the presence of foraminifer and ostracod shells indicates deposition may have taken place under low-energy environment in a relatively reduced oxygen contents lagoon (Geel, 2000; Corda and Brandano, 2003; Amao et al., 2016) The behaviour of Ti/Al, Fe/Al, Zr/Al and Si/Al can be exploited to acquire information on grain size (Dypvik and Harris, 2001). In the studied cores, Ti/Al and Fe/Al, and Zr/Al and Si/Al ratios show well correlations in the fine- and coarse grained horizons, which is matched by the muddy and sandy to sandy mud facies, respectively.In finer-grained sediments, Rb/Zr can be used as a proxy for changes in grain size, with lower values representing fine-grained material and higher values representing coarse-grained material. Increases in Zr/Rb proxy is matched by an increase in the coarse fraction in the sandy and sandy mud facies, as evidenced by the grain size analysis. A decrease in the Zr/Rb ratio is matched by an increase in clay fractions, in the muddy facies.

    Conclusion

    The sediment cores BAG, AZD and AM in the southern Iranian part of the coastal plain of the Caspian Sea, are dominated by mud and sand fractions. These sediment cores represent the Sandy mud, Sandy/silty sand and Muddy lithofacies. These lithofacies were deposited in the flood plain, beach and lagoon environments, respectively. The geochemical behaviour of most elements, in a general way, is related to the grain size in the sediments. Samples with high Si/Al and Zr/Al ratios are generally coarser grained, while high Ti/Al, Fe/Al and Rb/Zr are related to fine-grained samples.

    Keywords: Grain size, sedimentary facies, sea level changes, Caspian Sea