فهرست مطالب

پژوهش های دانش زمین - پیاپی 42 (تابستان 1399)
  • پیاپی 42 (تابستان 1399)
  • تاریخ انتشار: 1399/03/18
  • تعداد عناوین: 14
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  • آیدینگ کرنژادی، مجید اونق*، حمیدرضا پورقاسمی، عبدالرضا بهره مند، منوچهر معتمدی صفحات 1-18

    هدف از تحقیق پیش‌رو، پهنه‌بندی حساسیت زمین‏لغزش در حوزه‌ آبخیز اوغان، واقع در استان گلستان می باشد. بدین منظور از دو مدل توانمند داده کاوی شامل جنگل تصادفی و بیشینه آنتروپی استفاده گردید. زمین لغزش ها با استفاده از الگوریتم فاصله ماهالانوبیس به دو دسته 70 درصد (واسنجی پارامترها و تعلیم مدل ها) و 30 درصد (اعتبارسنجی نتایج مدل ها) تقسیم شدند. هم چنین با توجه به‌ مرور منابع گسترده، 15 عامل موثر بر وقوع زمین لغزش در منطقه موردمطالعه با روش تورم واریانس غربال، عوامل بهینه انتخاب و لایه های رقومی عوامل در سامانه اطلاعات جغرافیایی تهیه شدند. به منظور ارزیابی نتایج مدل ها (قدرت یادگیری و اعتبارسنجی نتایج) از مقدار مساحت زیرمنحنی تشخیص عملکرد نسبی با استفاده از دو دسته داده واسنجی و اعتبارسنجی استفاده شد. نتایج حاصل از ارزیابی قدرت یادگیری مدل ها نشان داد که مدل جنگل تصادفی و بیشینه آنتروپی به ترتیب با مقادیر سطح زیر منحنی 923/0 و 91/0 دارای قدرت یاگیری و برازش نسبتا مشابهی می باشند. اگرچه در مرحله اعتبارسنجی مشخص گردید که مدل جنگل تصادفی با مقدار 9/0 نسبت به مدل بیشینه آنتروپی با مقدار 85/0 قدرت پیش بینی و تعمیم نتایج بالاتری دارد. لذا مدل جنگل تصادفی به‌ عنوان مدل برتر در ارزیابی حساسیت زمین لغزش حوزه آبخیز اوغان معرفی گردید. براساس نتایج مدل جنگل تصادفی، حدود 10 درصد از حوزه آبخیز اوغان در پهنه حساسیت زیاد و خیلی زیاد به وقوع زمین لغزش قرار گرفته است. هم چنین، عوامل بارش، شاخص تفاضلی پوشش گیاهی نرمال شده، شاخص ارتفاع از سطح نزدیک‌ترین زهکش، سنگ شناسی و فاصله از جاده به‌عنوان مهم ترین عوامل موثر در وقوع زمین لغزش های منطقه معرفی گردیدند.

    کلیدواژگان: بیشینه آنتروپی، جنگل تصادفی، سامانه اطلاعات جغرافیایی، مدل های یادگیری ماشین
  • نعمت مال امیری، سید رضا حسین زاده*، علیرضا راشکی، مهناز جهادی طرقی صفحات 19-34

    پدیده گردو‌غبار یکی ‌از مخاطرات در کشور ایران و استان خوزستان محسوب می‌‌‌‌‌‌گردد. در این پژوهش با استفاده از عملیات میدانی‌ و آزمایشگاهی، مطالعه منابع گرد و غبار و قابلیت رخساره های مختلف برای تولید گرد و‌ غبار از مناطق غرب خوزستان صورت پذیرفته است. بر این اساس نقشه الگوی فضایی رخساره ها ترسیم و با استفاده از آن 12 شاخص فلزی ثابت در رخساره ها کاشته شد که بعد از سه روز گرد و غبار در زمستان 1396 و بهار 1397 (20/1/2018 و 19/2/2018 و 23/4/2018) اختلاف ارتفاع آنها اندازه‌گیری شد و همچنین نمونه های خاک سطحی از عمق 3-0 سانتی متر سطح زمین از نقاط مختلف منطقه نیز جمع آوری ‌گردید و آزمایش دانه‌سجی با الک خشک و هیدرومتری ‌برروی آنها صورت پذیرفت که نتایج نشان داد رسوبات عمدتا ریز دانه هستند و بیشترین تجمع رسوبات در سینی زیر الک دستگاه شیکر (رسوبات رد شده از الک 200) می‌باشد. همچنین نتایج هیدرومتری آشکار ساخت که در محدوده عمومی جفیر مقدار توزیع ذرات ماسه، سیلت و رس به گونه‌ای است‌که بافت خاک در این محدوده سیلتی رسی لومی می‌باشد و در نمونه های بستر خشک شده تالاب هورالعظیم و شمال سوسنگرد نیز همین نتایج صادق است. علاوه بر این در محدوده ریگ خوزستان میزان ماسه به شدت افزایش می‌یابد و در مقابل میزان رسوبات دیگر کاهش می‌یابد و بافت خاک از نوع ماسه ای لومی می‌باشد. ارزیابی شاخص ها مشخص کرد که در تمامی شاخص‌ها، رسوبات بستر رخساره ها در زمان بروز گرد و غبار منتقل می‌شوند به‌نحوی که بیشترین میزان جابه‌جایی در بستر شاخص های S4، S5 و S6 با تفاوتی بیش از 5 سانتی متر اندازه گیری ‌گردید. بنابراین براساس مطالعات صورت پذیرفته در این پژوهش فرسایش سطحی خاک در نواحی جفیر و زمین های خشکیده تالاب هورالعظیم دارای قابلیت گرد و غباری فراوان می باشد که می توان نقش آنها را در بروز و تشدید گرد و غبار در استان خوزستان موثر دانست.       

    کلیدواژگان: خوزستان، رخساره های مورفولوژیک، شاخص گذاری، گرد و غبار
  • سعید جانی زاده، احمد نوحه گر*، محمدتقی آوند، مجتبی دولت کردستانی صفحات 35-50

    فرسایش آبکندی یکی از اشکال فرسایشی است که موجب هدر رفت مقدار زیادی خاک می گردد. بنابرین از این فرسایش می توان به عنوان یکی از علل اصلی تخریب زمین و محیط زیست نام برد. این تحقیق با هدف پهنه بندی حساسیت فرسایش آبکندی با استفاده از مدل های داده کاوی، مدل خطی تعمیم یافته (GLM) و شبکه عصبی مصنوعی (ANN) در حوزه آبخیز رباط ترک انجام شد. مناطق دارای فرسایش آبکندی طی بازدیدهای میدانی شناسایی و تعداد 242 نقطه فرسایشی انتخاب گردید. 12 متغیر محیطی موثر در فرسایش آبکندی، نقشه رقومی ارتفاع، درجه شیب، جهت شیب، شکل شیب، شاخص همگرایی، فاصله از رودخانه، تراکم زهکشی، فاصله از جاده، سنگ شناسی، کاربری اراضی، شاخص اختلاف پوشش گیاهی نرمال شده (NDVI) و نقشه هم باران به منظور مدل سازی حساسیت فرسایش آبکندی مورد استفاده قرار گرفتند. به منظور ارزیابی و اعتبارسنجی مدل های مورد استفاده از معیارهای ROC، TSS و Kappa استفاده شد. نتایج حاصل از ارزیابی مدل نشان داد که مدل GLM با مقدار ROC، Kappa و TSS به ترتیب 89/0، 7/0 و 7/0 و مدل ANN با ROC، Kappa و TSS به ترتیب 88/0، 7/0 و 7/0 کارایی خیلی خوبی در مدل سازی مناطق حساس به فرسایش آبکندی دارند. همچنین بررسی کلی مدل های مورد استفاده براساس شاخص های ذکر شده نشان داد که مدل GLM دارای کارایی مناسب تری نسبت به مدل ANN در منطقه مورد مطالعه دارد. نتایج حاصل از پهنه بندی حساسیت فرسایش آبکندی در منطقه مورد مطالعه نشان داد که مناطق مرکزی حوزه دارای حساسیت خیلی زیاد و زیاد نسبت به فرسایش آبکندی می باشد.

    کلیدواژگان: فرسایش آبکندی، مدل های داده کاوی، منحنی ROC، حوضه آبخیز رباط ترک
  • ابوطالب محمدی، مجتبی یمانی*، ابراهیم مقیمی، ابوالقاسم گورابی، سید محمد زمانزاده صفحات 51-66

    یکی از عوامل زمین ساختی که نقش قابل توجهی در شکل زایی دارد، آتشفشان ها و مواد مذاب ناشی از آن ها است. فوران های آتشفشانی باعث دگرشکلی مورفولوژی و ایجاد ساختمان لندفرمی جدید می شود. آتشفشان دماوند با فوران های متوالی خود، طی کواترنری تغییرات قابل توجهی در پیرامون خود ایجاد نموده است. در این پژوهش، نقش گدازه های دماوند در تغییر مسیر رودخانه ها مورد بررسی قرار گرفته است. برای دستیابی به این هدف، روش تحلیلی و بازسازی زمانی تغییرات به کار گرفته شده اند. تکنیک کار بر مقایسه مورفومتری رودخانه ها و دامنه های مشرف به دره ها به سه روش مقایسه ارتفاع و ضخامت رسوبات آبرفتی، تعیین حدود گسترش رسوبات رودخانه ایی و دریاچه ایی و بازیابی آخرین حد ارتفاعی گدازه های مشرف به دره ها استوار است. رودخانه هراز به طور متوسط 4 کیلومتر، رودخانه دلیچای 3 کیلومتر و رودخانه لار 2 کیلومتر بر اثر گدازه های دماوند به مرور و طی فوران های متوالی تغییر مسیر داده اند. مسیر رودخانه ها عمدتا پس از شکل گیری دریاچه ها بر اثر انسداد دره ها و شکسته شدن سد ایجاد شده اند. قابل ذکر است که سطح اساس رودخانه های مذکور حدود 100 متر بالا آمده است.

    کلیدواژگان: تغییر مسیر رود، دماوند، دیرینه ژئومورفولوژی، رود هراز
  • کیوان عزی مند، حسین عقیقی*، یاسمن اسدی، محمد جوانبخت صفحات 67-88

    رشد پراکنده شهری منشا بسیاری از مشکلات شهرهای جهان و در نتیجه عدم برنامه‌ریزی و مدیریت مناسب است. این مطالعه به تحلیل فضایی و زمانی الگوی رشد شهری و پیش‌بینی آن در شهر رشت با هدف برنامه‌ریزی برای آینده پرداخته است. داده‌های مورد استفاده در این تحقیق شامل تصاویر لندست 5، 7 و 8 برای بازه زمانی 1987 تا 2017 است. روش انجام این تحقیق بدین ‌صورت است که با استفاده از شاخص NDISI اقدام به استخراج سطوح نفوذناپذیر شهری شده است سپس با استفاده از مدل سلول‌های خودکار- مارکوف اقدام به پیش‌بینی سطوح نفوذناپذیر شهری برای سال 2032 شده است. عملکرد این روش‌ها با استفاده از 300 نمونه که به‌صورت تصادفی انتخاب‌ شده است مورد ارزیابی قرار گرفته است. نتایج این مطالعه حاکی از دقت بالای شاخص NDISI برای استخراج سطوح نفوذناپذیر (12/86 تا 78/89 درصد)  بوده است. علاوه بر این، دقت مدل CA-Markov  برای پیش‌بینی سطح غیرقابل نفوذ در سال 2018 حدود 21/83 درصد بود. نتایج الگوی رشد شهری مشاهده ‌شده و مورد انتظار با یکدیگر تطابق نداشته و دارای اختلاف بوده‌اند. نتایج کلی تحلیل درجه آزادی (96/2 =) و آنتروپی شانون (08/3H=) حاکی از الگوی رشد پراکنده بوده‌اند. سپس H و  برای محاسبه درجه خوب بودن شهری (12/1G= -) مورد استفاده قرار گرفتند و این پارامتر نشان داد که الگوی رشد رشت نامناسب و بد است. این مشکل را می‌توان با برنامه‌ریزی شهری حل کرد.

    کلیدواژگان: آنتروپی شانون، درجه آزادی شهر، درجه خوب بودن شهر، سطوح نفوذناپذیر شهر، مدل پیش بینی سلول های خودکار- مارکوف
  • علی اصغر لشگری، جمیله توکلی نیا*، لطفعلی کوزه گر کالجی، زهره فنی، پگاه مریدسادات صفحات 89-109

    این پژوهش به دنبال ارزیابی برنامه ها و طرح های توسعه از منظر عدالت محیط زیستی با تاکید بر تکنولوژی سبز می باشد. بررسی وضع سیاستگذاری های محیط زیستی در برنامه های توسعه و اسناد فرادست شهری گویای این مهم است که متاسفانه نه تنها در اجرای برنامه ها عامل محیط زیست مدنظر کارگزاران شهری قرار نگرفته بلکه با بی توجهی به قوانین و مقررات در طرح های توسعه شهری و طرح های اقتصادی در بستر شهر، مشکلات عدیده محیط زیستی برای کلان شهر تهران ایجاد نموده است. از این رو یکی از راهکارهای پاسخگویی به این چالش ها توجه به مباحث عدالت محیط زیستی و به طور ویژه، تکنولوژی سبز است. پژوهش حاضر که یک پژوهش اسنادی با رویکرد تفسیری است. به دنبال واکاری مفاهیم عدالت محیط زیست در اسناد فرادست توسعه و شهری است. روش جمع آوری اطلاعات کتابخانه ای و تحلیل براساس نظر کارشناسان صورت گرفته است. نتایج پژوهش نشان می دهد که توجه به عدالت محیط زیستی از برنامه چهارم توسعه به بعد در بتن برنامه ها قرار گرفته است اما در عمل مورد بی توجهی قرار گرفته است. در اسناد فرادست شهری نیز ریوس کلی عدالت محیط زیست مطرح اما در اجرا همانند اسناد توسعه بوده است. همچنین نظر کارشناسان مهم ترین مانع سیاست گذاری عدالت محیط زیست شامل تعارض منافع و عدم توجه به توسعه فضای سبز و امکانات و تکنولوژی متناسب جهت سیاست گذاری عدالت محیط زیستی بوده است. افزون بر آن مهم ترین مولفه های موثر جهت دستیابی به عدالت محیط زیست در کلانشهر تهران شامل مولفه های اقتصادی(سرمایه گذاری و مالکیت خودرو)، اجتماعی(مشارکت آگاهانه و تصمیم سازی) و محیط زیستی(منابع تجدیدپذیر و توجه به تکنولوژی سبز) است.

    کلیدواژگان: عدالت زیست محیطی شهر، تکنولوژی سبز، کلان شهر تهران
  • ناصر شفیعی ثابت*، نگین سادات میرواحدی صفحات 110-126

    براساس واکاوی متون توسعه تا اوایل دهه 1980 میلادی، رویکرد عقلایی گرایی فن محور با اصالت متخصصین بر روش برنامه‌ریزی در اغلب کشورها غلبه داشت. این پژوهش به بررسی جایگاه شاخص‌های توانمندسازی متاثر از رویکرد حاکم بر فراگرد برنامه‌ریزی و پیامدهای حاصل از آن در توسعه پایدار سکونتگاه‌های روستایی پرداخته است. در این راستا، با اینکه توانمندسازی مولد روستاییان تضمین‌کننده توسعه روستایی است، لیکن برنامه‌ریزی از بالا به پایین و متخصص محور موجب توانمندسازی نامولد روستاییان در ناحیه موردمطالعه شده است و نتوانسته آن‌ها را به‌مثابه یکی از عناصر قدرت در حوزه مداخله‌ی برنامه‌ریزی روستایی درآورد. برای تبیین دقیق موضوع مسیله، پژوهش حاضر با استفاده از روش توصیفی - تحلیلی بر روی 54 روستای نمونه از 124 روستای ناحیه موردمطالعه انجام شد. در واقع رویکرد برنامه‌ریزی متخصص محور به‌صورت سلطه آمیز نتوانسته احساس معنی دار بودن، شایستگی، خودباوری، اعتماد، قدرت و توانمندی را در بین روستاییان ایجاد نماید. به‌گونه‌ای که باعث نارسایی در توسعه سکونتگاه‌های روستایی در ابعاد محیطی - اکولوژیک، اجتماعی – فرهنگی و اقتصادی شده و تنها در ارتقاء شاخص‌های کالبدی و زیرساختی روستاهای موردمطالعه اثرگذار بوده است. بنابراین، تغییر به‌سوی رویکرد اجتماع‌محور به‌منظور ارتقاء شاخص‌های توانمندسازی و توسعه پایدار روستایی پیشنهاد می‌گردد.

    کلیدواژگان: توانمندسازی، توسعه روستایی، شهرستان های پاکدشت و ری، رویکرد برنامه ریزی متخصص محور
  • احمد آریافر*، وحید خسروی، محمدامین فرشادمهر، سعید یوسفی صفحات 127-142

    انتخاب مناسب ترین روش برای شناسایی مقادیر آنومالی از زمینه یکی از چالش های مهم در زمینه اکتشافات ژیوشیمیایی می باشد. در این خصوص روش هایی همچون روش های آماری، هوش مصنوعی، محاسبات نرم و روش های ترکیبی توسعه یافته اند که هریک از این روش ها دارای مزایا و معایبی می باشند. هدف این تحقیق شناسایی پتانسیل های معدنی عناصر طلا، آرسنیک و آنتیموان در برگه 1:100000 بصیران با استفاده از مدل ترکیبی فاکتوری- فرکتالی است. برای این منظور تعداد 585 نمونه ژیوشیمیایی اخذ شده از رسوبات آبراهه ای که برای 20 عنصر آنالیز شده است مورد مطالعه قرار گرفت. برای رسیدن به هدف ابتدا داده ها توسط روش فاکتوری R مد مطالعه و تعداد 5 فاکتور استخراج گردید که با توجه به هدف، فاکتور سوم که ترکیب خطی از عناصر آنتیموان، آرسنیک و طلا بود انتخاب شد. مقادیر امتیازات فاکتوری محاسبه و نقشه امتیازات فاکتوری رسم شد. سپس روش فرکتالی غلظت -مساحت بر روی امتیازات فاکتوری مولفه سوم اعمال و مقادیر حد آستانه تعیین گردیدند و در نهایت براساس این مقادیر نقشه مدل ترکیبی فاکتوری- فرکتالی رسم شد. مقایسه این نقشه با نقشه فرکتالی غلظت - مساحت نشان داد که شدت بخشی آنومالی ها با مدل ترکیبی بهتر انجام شده است. به منظور اعتبارسنجی نتایج حاصله از مدل ترکیبی، تعداد 6 نمونه کانی سنگین از منطقه اخذ و مطالعه شد. نتایج حاصله از مطالعات کانی سنگین بیانگر وجود ذرات طلا در این نمونه ها بود. مقایسه نتایج مطالعات کانی سنگین و مدل های آماری نشان می دهد که انطباق خوبی (بیش از 90 درصد) بین نتایج وجود دارد زیرا که نمونه های کانی سنگین منطبق بر نواحی آنومالی می باشد.

    کلیدواژگان: بصیران، خراسان جنوبی، رسوبات آبراهه ای، ژئوشیمی ناحیه ای، مدل ترکیبی فاکتوری- فرکتالی
  • معصومه اقبالی*، بهاءالدین حمدی، محمودرضا مجیدی فرد صفحات 143-158

    به منظور مطالعه عناصر کنودونتی، سازند شیشتو 1 برش در حوض دوراه انتخاب و مورد بررسی قرار گرفت. برش مورد مطالعه دارای توالی تخریبی – کربناته است که شامل 152 متر سنگ آهک، ماسه سنگ و شیل است. همبری زیرین سازند شیشتو 1 بر روی سازند بهرام به صورت ناپیوسته و همبری بالایی آن با سازند شیشتو 2 به طور پیوسته است. این سازند دارای ماکروفسیل هایی همچون بازوپا، مرجان، ساقه لاله وش، گونیاتیت و میکروفسیل هایی همچون، کنودونت، فرامینیفر و بقایای موجودات دیگر (خار اسفنج، گاستروپود، ساقه لاله وش) می باشد. براساس مطالعات میکروسکوپی توالی سازند شیشتو 1 در برش حوض دوراه 4 جنس، 13 گونه، 4 زیر گونه با 4 زیست زون کنودونتی به دیرینگی دونین پسین (فرازنین پیشین– فامنین پسین) شناسایی و معرفی گردید که معادل با زیست زون استاندارد جهانی می باشند: Polygnathus webbi- Polygnathus dubius Concurrent Range Zone = Falsiovalis - jamieae Biozone Icriodus symmetricus-Icriodus expansus Interval Range Zone= Rhenana – linguiformis Biozone Icriodus cornatus- Palmatilepis grasilis grasilis Concurrent Range Zone= Triangularis –trachytera Biozone Polygnathus delicates Total Range Zone= Expansa – praesulcata Biozone و 6 جنس، 13 گونه و 2 زیرگونه مربوط به بخش زیرین سازند شیشتو 2 به دیرینگی تورنزین پسین – ویزین پسین با 2 زیست زون کنودونتی شناسایی و معرفی گردید. Gnathodus girtyi cuneiformis- Gnathodus typicus Interval Range Zone = Crenulata – typicus Biozone Gnathodus pseudosemiglaber- Gnathodus collinsoni Concurrent Range Zone = Ancholaris- latus – texanus Biozone

    کلیدواژگان: برش حوض دوراه، دونین پسین، سازند شیشتو 1و2، کنودونت، فرازنین- فامنین
  • مهین فرهادیان بابادی*، بهزاد مهرابی، فرانکو تاسی، مایکل زلنسکی، ایلیا چپلیگین، عطا شاکری، استفانیا ونتوری صفحات 159-174

    گل فشان ها مجراهای مهاجرت رو به بالای سیالات عمیق پرفشار در حوضه های رسوبی در نتیجه نیروهای عمدتا فشارشی هستند. گل فشان پیرگل به عنوان بزرگ ترین گل فشان ایران بین دو آتشفشان تفتان و بزمان در جنوب شرق ایران واقع شده است. مطالعات ژیوشیمیایی و ایزوتوپی بر روی گازهای منتشر شده از مکان های تراوش فعال این گل فشان برای تعیین منشا گازهای هیدروکربوری و غیرهیدروکربوری انجام شد. داده های ترکیب شیمیایی گاز نشان می دهد که دی اکسیدکربن گاز خروجی غالب و متان دومین گاز خروجی در این گل فشان است. مقادیر کمی از گازهای هیدروکربوری سنگین تر مانند اتان، پروپان، ایزوبوتان و ان- بوتان هم مشاهده شد. منشا ترموژنیک گازهای هیدروکربوری توسط نسبت متان به مشتقات هیدروکربوری سنگین تر (C1/C2+) پایین و مقادیر δ13C متان  از 7/40- تا ‰ 2/42- آشکار می شود که ممکن است مرتبط با شکستن حرارتی موادآلی ناشی از وجود فرآیندهای حرارتی یا منابع گرمایی باشد. حضور گازهای هیدروکربنی ترموژنیک در گل فشان پیرگل می تواند بیانگر احتمال حضور سیستم هیدروکربوری در این منطقه باشد. مقادیر ایزوتوپی کربن دی اکسیدکربن  از 9/11- تا ‰8/13- در گازهای تجزیه شده نیز حدواسط بین دی اکسیدکربن تولید شده در طی فرآیند ترموژنیک موادآلی و دی اکسیدکربن ناشی از سیستم های آتشفشانی است. نقش گوشته بالایی به عنوان یکی از منشاهای احتمالی گازهای خروجی از گل فشان پیرگل توسط مقادیر ایزوتوپی هلیم 3He/4He از 58/1 تا  R/Ra61/1 مشخص می شود که ممکن است مرتبط با حضور سیالات سیستم های زمین گرمایی منطقه باشد.

    کلیدواژگان: ایزوتوپ های هلیم، دی اکسیدکربن، گازهای هیدروکربوری و غیرهیدروکربوری، گل فشان پیرگل
  • مریم کیا اشکوریان*، علی اصغر کلاگری، علی عابدینی، غلامحسین شمعانیان صفحات 175-192

    نهشته لاتریتی سپارده در منطقه اشکورات در استان مازندران و در مرز بین سازندهای الیکا و شمشک محصور شده است. مطالعات ساختی و بافتی نشان‌دهنده خاستگاه برجازا و نابرجازا برای این نهشته است. بررسی‌های کانی‌شناسی آشکار می‌کنند که کانی‌های سیدریت، شاموزیت، کایولینیت، بوهمیت، دیاسپور، هماتیت، گوتیت، کلینوکلر و آناتاز فازهای کانیایی اصلی این کانسنگ‌ها هستند که توسط فازهای فرعی روتیل، موسکویت و لپیدوکروسیت همراه می‌شوند. این مجموعه کانیایی پیشنهاد‌کننده آن است که آب‌های زیرزمینی با ماهیت بازی- احیایی و آب‌های سطحی با ماهیت اسیدی- اکسیدان نقش مهمی در تشکیل این نهشته ایفا نموده‌اند. با توجه به رفتار زمین‌شیمیایی عناصر اصلی به نظر می‌رسد که کانسنگ‌های لاتریتی طی فرآیندهای لاتریتی‌شدن متوسط تا شدید تشکیل شده‌اند. براساس آنالیزهای شیمیایی، مقادیر REEها در کانسنگ‌ها در بازه‌ای از 91/58- 72/846 ppm متغیر است. مقادیر La/Y، Eu/Eu*، و Ce/Ce* در کانسنگ‌ها به ترتیب دارای بازه 34/0- 76/3، 76/0- 24/1 و 92/0- 41/2 می‌باشند. بررسی‌های زمین‌شیمیایی نشان داد که تغییر در شرایط فیزیکوشیمیایی محیط تشکیل (pH و Eh)، عملکرد سنگ بستر کربناتی به عنوان یک سد زمین‌شیمیایی، کمپلکس‌شدن با لیگندهای کربناتی، اختلاف در میزان پایداری کانی‌های حامل عناصر نادر خاکی و تثبیت در فازهای نیومورف نقش مهمی در توزیع و تحرک عناصر نادر خاکی در طی تشکیل و تکامل افق لاتریتی در سپارده ایفا نموده‌اند. علاوه بر این، ناهنجاری‌های Eu به همراه نسبت‌های TiO2/Al2O3 و Sm/Nd مبین سنگ‌های آندزیتی و بازالتی تریاس فوقانی به عنوان منشاء احتمالی برای نهشته سپارده می‌باشند.

    کلیدواژگان: عناصر نادر خاکی، کانی شناسی، لاتریت، سپارده، اشکورات
  • بابک سامانی*، عادل ساکی، سحر تقی زاده صفحات 193-208

    در این پژوهش با استفاده از عناصر ساختاری به مطالعه فازهای دگرشکلی و پارامترهای استرین در شیست های آندالوزیت دار جنوب شرق همدان پرداخته شده است. در این تحقیق با استفاده از تحلیل استریوگرافی عناصر برگوارگی و خطوارگی، الگوی صفحات فاقد طویل شدگی نهایی به عنوان معیاری جهت تحلیل استرین نهایی مورد بررسی قرار گرفته است. نتایج نشان دهنده وقوع دو فاز دگرشکلی در منطقه می باشد. مقادیر نسبت استرین در اولین فاز دگرشکلی به صورت Rxz=4.3، Rxy=2.2 و Ryz=1.9  و مقادیر نسبت استرین برای دومین فاز دگرشکلی به صورت Rxz=3.6، Rxy=2.0 و Ryz=1.8 محاسبه گردید. فاکتور شکل بیضوی استرین (k) در هر دو فاز دگرشکلی نشان دهنده بیضوی کشیده شده سه محوری می باشد. تاثیر دومین فاز دگرشکلی به صورت تغییر موقعیت محورهای متوسط و کوچک بیضوی استرین در نتیجه چرخش حول محور بزرگ استرین می باشد. به احتمال زیاد این تغییر جهت یابی محورهای استرین در نتیجه نفوذ و جایگیری توده باتولیت الوند می باشد. محاسبه مقادیر عدد جنبش شناختی تاوایی حاکی از غالب بودن مولفه استرین برشی ساده در هر دو فاز دگرشکلی می باشد. 

    کلیدواژگان: بیضوی استرین، استرین نهایی، عدد جنبش شناختی تاوایی، سطوح فاقد طویل شدگی نهایی
  • حمیدرضا ناصری، مرضیه سعیدی*، فرشاد علیجانی، صادق علیمرادی صفحات 209-224

    روستای فرخ آباد در حدود پنج کیلومتری جنوب غرب شهر دهلران واقع شده است. عمق کم سطح آب زیرزمینی در گستره ی این روستا باعث بروز مشکلاتی برای اهالی روستا شده و زندگی روزمره آنها را مختل کرده است. در این پژوهش استفاده از سیستم زهکشی برای پایین انداختن سطح آب زیرزمینی دشت فرخ آباد مورد ارزیابی قرار گرفته است. در این مدل، ابتدا اطلاعات میزان بارندگی و تبخیر در گستره دشت، میزان تغذیه و تخلیه آبخوان از طریق کانال های آبیاری، مسیر رودخانه میمه و همچنین میزان برداشت آب از چاه ها و تغذیه آبخوان از فاضلاب برگشتی به نرم افزارVisual MODFLOW  وارد شد. سپس رفتار هیدرولیکی آبخوان دشت با استفاده از نرم افزار مدل سازی شد. پس از واسنجی و صحت سنجی مدل، تاثیر اجرای سیستم های مختلف زهکشی بر تراز سطح آب زیرزمینی دشت در قالب سه سناریوی شرایط هیدرولوژیک مرطوب، عادی و خشک شبیه سازی شد. براساس سناریوی اول افت سطح ایستابی در دوره مرطوب و عادی چهار تا پنج متر و در دوره خشک  دو تا سه متر خواهد بود. نتایج حاصله نشان دهنده برتری روش زهکشی زیرزمینی(سناریوی اول) نسبت به احداث چاه های پمپاژ (سناریوی دوم) در پایین انداختن سطح ایستابی گستره مورد مطالعه می باشد. 

    کلیدواژگان: آب زیرزمینی، دشت فرخ آباد، زهکشی زیرزمینی، شبیه سازی، Visual MODFLOW
  • بهمن رحیم زاده*، پروین شکرالهی، غصون زهیره، فریبرز مسعودی صفحات 225-246

    منطقه دهگلان در شمال غرب ایران واقع شده است و قسمتی از زون سنندج- سیرجان می‌باشد. در این محدوده چندین واحد آتشفشانی حد واسط تا اسیدی به سن میوسن فوقانی- پلیوسن رخنمون دارند. سنگ‌های این منطقه عمدتا ترکیب آندزیت تا تراکی‌آندزیت و داسیت دارند. فنوکریست‌های آن‌ها عمدتا از پلاژیوکلاز، هورنبلند و بیوتیت تشکیل شده است. کلینوپیروکسن با فراوانی بسیار کم در فنوکریست‌ها نیز قابل ملاحظه می‌باشد. در این مطالعه با استفاده از ویژگی های کانی شناسی به بررسی ترکیب، کینتیک تبلور کانی ها و ژنز سنگ‌های شمال دهگلان پرداخته شده است. نتایج حاصل از آنالیز نقطه‌ای کانی‌ها در این سنگ‌ها نشان می‌دهند که ترکیب پلاژیوکلازها از آندزین تا الیگوکلاز در تغییر بوده و منطقه‌بندی در آنها دیده می‌شود. آمفیبول‌ها عمدتا از نوع هورنبلند ادنیتی و مگنزیوهورنبلند، کلینوپیروکسن‌ها از نوع اوژیت و بیوتیت از نوع بیوتیت منیزیم‌دار هستند. بیوتیت‌ها اکثرا از نوع ماگمایی اولیه بوده و بین دو قطب فلوگوپیت و آنیت قرار گرفته‌اند. فوگاسیته اکسیژن ماگما براساس شیمی آمفیبول و کلینوپیروکسن در زمان تبلورشان بالا بوده است. بر مبنای ترکیب کلینوپیروکسن و بیوتیت ماهیت ماگمایی اولیه سازنده و محیط تکتونیکی سنگ‌های میوسن بالایی- پلیوسن کالک‌آلکالن بوده که در قوس‌ مرتبط با فرورانش در حاشیه قاره‌ای فعال تشکیل شده‌اند. کلینوپیروکسن‌ها به طور متوسط در فشار 5 تا 6 کیلوبار و دمای حدود 1000 تا 1110 درجه سانتی‌گراد، آمفیبول‌ها در فشار 4 تا 6 کیلوبار و دمای بین 724 تا 862 درجه سانتی‌گراد، پلاژیوکلاز در دمای بین 550 تا 750 درجه سانتی‌گراد و بیوتیت در دمای 715 درجه سانتی‌گراد متبلور شده‌اند.

    کلیدواژگان: آداکیت، دما-فشار سنجی، دهگلان، سنندج- سیرجان، شیمی کانی
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  • Aiding Kornejady, Majid Ownegh*, Hamid Reza Pourghasemi, Abdolreza Bahremand, Manouchehr Motamedi Pages 1-18
    Introduction

    Landslide susceptibility maps are considered a backbone for decision-makers to suggest solitary or combined technical and regulatory measures. Such maps are also considered an invaluable tool for engineers, earth scientists, planners, and decision-makers to select the most suitable areas for agriculture, building, and other development activities. Hence, thanks to landslide susceptibility maps, addressing highly susceptible areas are feasible, so that over the course of further detailed studies on the imminent landslide occurrences in the future, landslide potential risk is mitigated.

    Materials and methods

    In this study, two robust data mining models, namely random forest and maximum entropy were used to map landslide susceptibility across the Owghan Watershed in Golestan province. After preparing the landslide inventory map via extensive field surveys, interpreting Google Earth images, and the archived data acquired from different organizations, landslide points were split into two sets of training (70%) and validation (30%) by using the Mahalanobis distance technique. Further, drawing on the extensive literature review, fifteen factors including climatic, geological, tectonic, topo-hydrological, and anthropogenic drivers, as landslide-controlling factors were selected and sieved through the variance inflation factor test. Ultimately, by implementing the above-mentioned data mining techniques, the most important factors in the modeling process, as well as the highly susceptible locations in the study area, were introduced.

    Results and discussion

    Evaluating the learning capability, both the random forest and maximum entropy models with the respective area under the receiver operating characteristic curve (AUROC) values of 0.923 and 0.91, showed almost identical fitting abilities. However, getting to the validation stage, it was found that the random forest with the AUROC value of 0.9 clearly outperforms maximum entropy (AUROC= 0.85) in terms of prediction power and generalization capacity. Hence, the random forest was suggested as a better-performing model for landslide susceptibility mapping in the Owghan watershed, compared to its counterpart. About 10% of the study area falls into high and very high landslide susceptibility zones. Furthermore, five landslide-controlling factors including rainfall, normalized difference vegetation index, height above the nearest drainage, lithological formation, and proximity to roads have been found to be the most significant factors contributing to landslide occurrence in the study area. Additionally, the results attest that announcing the Safiabad village as a landslide-prone area by the authorities is technically sound and evacuating the residents to a new place has been a right decision; however, some parts of the newly inhabited area shows landslide predisposing patterns which can lead to a higher susceptibility of the area to landslide occurrence in the future.

    Conclusion

    Scrutinizing the results of random forest model revealed that a combination of natural factors (intense rainfall, bare lands, susceptible lithological formations, and topo-hydrological mechanisms) and anthropogenic interferences (tillage parallel to slope length/perpendicular to contour lines and unprincipled road construction) are synergistically responsible for landslide occurrence in the Owghan Watershed. On the other hand, announcing the Safiabad village as a critical landslide-prone area seems to be a wise decision, although the newly inhabited place seems to be selected merely based on having a suitable slope steepness (i.e., almost flat) and being accessible through several connecting routes, while the enhanced conservation tillage methods have not been applied to the selected site and adjacent areas. The latter, according to our inferences, can trigger a crisis in a larger extent. Moreover, owing to the presence of other landslide predisposing factors in the new residential site, safe areas should be pointed out and announced by adopting a holistic view on the entire influential and predisposing conditions for landslide occurrence.

    Keywords: Maximum entropy, Random forest, Geographical information system, Machine learning models
  • nemat malamiri, Seyed Reza Hosseinzadeh*, Alireza Rashki, Mahnaz Gahadi Toroqhi Pages 19-34
    Introduction

    A dust storm is a common environmental hazard in the Iran, especially in Khuzestan province. It is important to note that the temporal and spatial variations of dust cause the dust to diffuse from different facies. Accordingly, various methods have been developed to identify dust sources, most notably the use of field and laboratory work. Therefore, in this study, we study the internal dust sources and different facies capabilities for producing dust from western Khuzestan.

    Materials and methods

    In this study, first, a spatial map of the facies was prepared in which the Landsat 8 and Sentinel 1 satellite images were used on 21/4/2018. Then, three metal rods were planted in all faces using fieldwork. Then the height difference of the rods was measured in three consecutive time periods after the dust storms in winter and spring 2018. Also, surface samples (0-3 cm) were collected at the rod location. The samples were transferred to Ferdowsi University laboratory and grain size analysis was performed. Finally, a hydrometric test was carried out to determine soil mineral and soil texture.

    Results and discussion

    The results showed that the sediments are predominantly fine-grained, with the highest accumulation of sediment under the sieve of the shaker. Also, Hydrometric results indicated that the Jofer area has silty clay loamy soil and in the dry bed samples of the Hoor_Al_Azim Wetland and north Susangerd, the results are similar to the Jofer area. Assessment of the rods illustrated that bed sediments were transported at the time of dust formation. The maximum displacement was measured at the location bed S4, S5, and S6 with a difference of more than 5 cm.

    Conclusion 

    In this study, the internal dust sources were studded and different facies capabilities for producing dust from western Khuzestan were measured. Results indicate the sediments due to environmental conditions are not coherent and have no solidarity. In addition, internal border sources of dust have been found to play a major role in the spread of dust in western Khuzestan.

    Keywords: Khuzestan, Morphological facies, Evaluation, Dust storm
  • Saeid Janizadeh, Ahmad Nohegar*, Mohammadtaghi Avand, Mojtaba Dolat Kordestani Pages 35-50

    Soil erosion is a problem for agriculture in arid and semi-arid regions and is of great importance due to its long-term effects on soil fertility and sustainable agriculture. Among the types of water erosion, gully erosion is one of the most important events in soil erosion and land reclamation. Given that the Markazi province is located in a region with arid and semi-arid climate, the intensity of rainfall is high in some months of the year. Also because of the abandoned agricultural land in the study area, there is much vegetation exposed to severe erosion which is conducive to erosion such as gutter erosion, so serious attention is needed for this area. The data mining method extracts useful information from a large volume of data and has shown good performance based on the literature review. Therefore, the aim of the present study was to prioritize environmental factors affecting the occurrence of gully erosion with data mining and statistical methods.

    Material and Methods

    In order to conduct the present study and to map the distribution of gully erosion zones in the Robat Turk watershed, 242 gully data were identified in the study area and used. A total of 242 points were identified as non-flooded areas. In order to model the data, it was divided into two categories of training and validation, with 70% of data used as training and 30% of data used as validation. Based on the research background, hydrological, geological and physiographic factors including elevation, slope, aspect, curvature, slope shape, distance from river, distance from road, lithology, land use, annual precipitation and NDVI, variables were selected for modeling. In order to model the gully erosion, artificial neural network (ANN) and generalize linear model (GLM) models were used, and the ROC and Kappa, TSS coefficient were used to determine the accuracy of the gully erosion susceptibility map.

    Result and discussion

    The results of gully erosion susceptibility showed that the central areas of the watershed are highly sensitive to erosion. Considering that most of the lands in the central part of the watershed are bare land and agricultural, the study of the gully erosion susceptibility map showed that the most sensitive and highly sensitive erosion susceptibility area was formed in the bare land. In relation to the influence of different elevation and slope classes in the study area on susceptibility to erosion, it should be stated that altitude class of 1800-2000 meters and slope class of 0-12% had the highest contribution to erosion susceptibility in the study area. This may be due to the higher soil compactness of these classes than other classes, which increases the likelihood of water infiltration into the soil and the possibility of material dissolution and piping. Validation results showed that GLM and ANN with ROC of 0.89 and 0.88 have very good performance regarding gully erosion susceptibility in the study area.

    Conclusion

    Gully erosion is one of the erosion processes that widely affects the appearance of the earth. In this study, GLM and ANN were used to evaluate the impact of environmental variables on gully erosion as well as to identify potential areas for gully erosion. For this purpose, 12 variables and 242 gully erosion points were used. ROC, TSS and KAPPA statistics were used to evaluate the models. The results of evaluation and validation of the models used showed that both models have good performance in zoning susceptibility to gully erosion. Identification and prediction of gully erosion susceptible areas can reduce the damaging effects of this type of erosion and prevent its further development and can be of considerable help to the people of the study area. Given that most of the gutters were created in the central part of the study area near the village of Robat Turk, protective measures should be increased in these areas to prevent the spread of agriculture and residential areas to erosive areas.

    Keywords: Gully erosion, Data mining models, ROC curve, Rabat Turk watershed
  • Abotaleb Mohammadi, Mojtaba Yamani*, Abrahim Moghimi, Abolghasem Gorabi, Seyed Mohammad Zamanzadeh Pages 51-66
    Introduction

    One of the tectonic factors that play a significant role in the formation is the activity of volcanoes and the flow of volcanic materials. The volcanic eruptions cause morphology and create new landforms. Damavand volcano with its successive eruptions during the Quaternary has made significant changes to its surroundings. In this study, the role of Damavand lava flows in changing the bed rivers has been investigated. The main purpose of this study was to investigate the effects of the latest Damavand volcanic eruptions on the behavior and direction of these bed rivers around it. Materials and Methods The technique has been based on three main

    methods

    1) Comparison of the height and thickness of sedimentary deposits obtained through the morphometry of transverse profiles on the fieldworks. 2) Determination of the extent of lake sediment distribution in the Haraz, Lar and Delichai areas, which is transmitted on the map based on field data and GPS coordinates. 3) The extent and altitude of the lava flows overlooking the Haraz, Lar and Delichai valleys have been recorded and transferred to the maps. In addition, much of the data was obtained through indirect observations through satellite imagery and then combined with field findings. To achieve this, the length of the rivers is divided into two distinct intervals. Then morphometric data of valleys, sedimentary evidences and dynamics of rivers in the form of the mentioned intervals are studied and compared temporally and spatially. At the analysis stage, the above data have been adjusted with the radial pattern of the drainages around Damavand to the main grid as well as the volcanic cone structure and then the longitudinal routes of the rivers have been reconstructed.

    Results and Discussion

    Evidence indicates that there was no significant change in the waterway during the Abask interval toward Amol and the outlet of the basin (Interval 1). However, in the Abask-to-Plour (Interval 1) range, the presence of lava gravels carried by the Haraz River and deposited in the northwest of the Abask landslide indicates that the river changes over time. Also, the lava flows overlooking the Haraz valley represent major changes that have occurred in the past. In this regard, the Haraz River has dug up to a depth of 100 meters in the sediments of lakes and rivers. The amount of river diversion at the intersection of the Lasem River to the Haraz River (Interval 1) and the displacement of the river bed is approximately 4400 meters from its present bed. The modified route in the second interval is about 4200 meters. The bed river of the Haraz River redirection from the old Plour Bridge to the intersection of the Haraz and Lasem (interval 1) is about 1600 meters. Reconstruction of the old Haraz River bed route indicates that the stream has stretched past the eastern part of the Tizkuh sedimentary slope. The average redirection of the Haraz River in this interval is estimated at about 1000 meters. In the second interval, the most deliberate distance of the Delichai River is the intersection of this river with the Lar River. This displacement is estimated to be about 4100 meters. Damavand lava flows in this region have created a lava barrier along the Delichai River Route, changing the east-west direction. The mean flow direction of the Delichai River is estimated to be 2500 meters. In addition, studies indicate that as a result of the formation of lava dams, the base level of the above-mentioned rivers has also risen by an average of 100 m above the level of its original base level, prior to the Damavand eruption.

    Conclusion

    The results indicate that there have been major changes except for one in two intervals, and that these changes have occurred in two major forms. One is the formation of lava dams caused by Damavand eruption, which has caused major changes in the longitudinal profile of the rivers and the deepening, formation of gullies and then filling of the canals are three forms of this process. There are four levels of terrace that illustrate this. Secondly, the diversion of rivers occurred in the second and third intervals, where the presence of river deposits beneath the lava flows as well as the general topography of the valleys can clearly identify the longitudinal paths of the waterways in these two intervals.

    Keywords: River diversion, Damavand, Paleogeomorphology, Hazar river
  • Keyvan Ezimand, Hossein Aghighi*, Yasaman Asadi, Mohamad Javanbakht Pages 67-88
    Introduction 

    The world is rapidly moving towards urbanization, and with large populations living in cities, and ever increasing population in urban areas, urban sprawl has occurred in many cities around the world. Lack of urban planning and management regarding the development of urban sprawl has been known as the source of many problems in cities around the world. Urban sprawl negatively impacts the environment, quality of life, social equity, climate change, air pollution and LST. Therefore, one of the goals of this study is to show the pattern of urban growth from the past to present, and predict the future of urban growth that may occur. It can be considered as an innovation of this study, which was less prominent in previous studies.

    Materials and methods

    The study area is Rasht, where its natural attractions and tourism characteristics have increased its population and physical development. This research utilized Landsat 5 (TM), 7 (ETM+), and 8 (OLI/TIRS) images. In the first step, the pre-processing operations including geometric correction, atmospheric correction, and radiometric correction were performed on the remote sensing images. In the next step, Normalized Difference Impervious Index (NDISI) values were computed and employed to extract the impervious surface information in urban area. Then a hybrid cellular automaton–Markov (CA-Markov) model was used to predict both the quantity and spatial distribution of impervious surfaces in the city of Rasht. The performances of these methods were evaluated using 300 randomly selected samples. Finally, statistical analysis has been used to show the growth pattern of Rasht from its past to present and also to predict the future.

    Results and discussion

    The results of this study indicated that the impervious surface of this city can be extracted with high accuracy (from 86.12 percent to 89.88 percent) using NDISI computed from Landsat images. Moreover, the accuracy of the CA-Markov model through prediction of impervious surface for the year 2018 was about 83.21 percent. With regard to the results of this work, the observed and expected urban growth results are not consistent with each other. The analysis of degree-of-freedom ( ) and Shannon's entropy ( ) are reflecting the urban sprawl pattern. Then, H and were used to compute the degree of goodness ( ). This parameter demonstrated that the growth pattern of Rasht was inappropriate.

    Conclusion

    This study shows that the sprawl of the city of Rasht can be characterized by a scattered growth that is expected to be worse in future, if management measures are not taken by governmental authorities. The results of this study can be useful for future urban planning and decision making such as preventing vertical land use changes.

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  • Aliasghar lashgary, Jamileh Tavakolinia*, Lotfali Kozehgarkaleji, Zohreh Fanni, Pegah moridsadat Pages 89-109

    Environmental issues in the field of institutional management from the global to the local level, have always been a complex problem for planners and decision-makers. This fact has faced major challenges in cities and especially in metropolitan areas because of the concentration of economic and demographic activities, a kind of planning system and mechanism. Therefore, every management system has sought to solve these problems from the planning level to the implementation. The reflection of these plans and the determination of environmental problem-solving strategies has mirrored in the plan and program, and this research also seeks to evaluate developing plans and programs. Investigation of environmental policy making in urban development plans and documents indicates its importance but unfortunately, implementation of environmental agent programs has not been considered by decision-makers in their programs but also, ignoring the laws and regulations in urban development plans and economic plans in the context of the city has created enormous environmental problems for Tehran metropolis. Therefore, one of the solutions to tackle these challenges is to address environmental justice discussions, with emphasize on, green technology. The present study is a documentary research with an interpretive approach. It seeks to embody the concepts of environmental justice in the urban development documents. The present study aimed to see whether environmental justice policy-making has emphasized green technology in national development programs. Whether outreach documents in Tehran metropolis, identify the barriers and challenges of comprehensive policy-making in achieving urban environmental justice with an emphasis on green technology. Also recognizing the most important factors which can contribute to the achievement of environmental justice in the city by focusing on green technology is a study goal.

    Materials and methods 

    The method of data gathering is library information and analysis based on expert's opinion. The results show that attention to environmental justice has been placed in the center of plans from the fourth development plan onwards. But in practice it has been neglected.

    Results and discussion

    Environmental issues due to their role in human life have always attracted the attention of planners and the whole system of management. The present study aimed to evaluate the state of environmental justice by focusing on green technology by considering five-year economic, social, and cultural development plans. In fact, the programs leading to prevention of environmental justice in the metropolis of Tehran were evaluated in the present study. It is different from other studies by focusing on environmental justice with respect to green technology for evaluating development plans. Based on the results, lack of involvement of environmental sectors in implementing the programs, lack of financing, and lack of appropriate environmental infrastructure based on development plans were considered problems which prevented Tehran from achieving environmental programs and environmental justice.

    Conclusion

    In urban documents the environmental justice outline has been presented, but in implementation it had been ignored. According to experts, the most important obstacle to environmental justice policy making is conflict of interests and lack of attention to the development of green space and appropriate facilities and technology that have focus on environmental justice policy. In addition, the most important components for achieving environmental justice in Tehran metropolis include economic components such as: car investment and ownership, informed social participation and decision-making, and renewable environmental resources and attention to green technology.

    Keywords: Urban environmental justice, Green technology, Tehran metropolis
  • Negin Sadat Mirvahedi Pages 110-126
    Introduction 

    Paying attention to empowering rural stakeholders with emphasis on community approach in planning was proposed by Jürgen Habermas and then Forster (1993, 1989, 1985). In the area, a set of plans and projects are planned for the villagers by various organizations. The dominance of the "expert- oriented " and "top-down" approach in the development planning process in Iran has had detrimental environmental, ecological, socio-economic impacts on rural settlements in the study area. It is necessary to analyze the implications of this planning for the process of sustainable rural development in the area.

    Materials and methods

    In fact, the purpose of the present survey is to identify and explain the consequences of planning with its current approach to sustainable development in rural areas of the study area. Also the factors and indicators of empowerment influenced by the development planning system's approach in the rural areas are analyzed.The present survey was carried out using descriptive-analytical method to investigate the status of planning with an expert- oriented approach in the area and to explain the research questions and hypotheses in detail. The statistical population of the present survey is a total of 124 villages in rural settlements of Pakdasht and Rey counties around Tehran metropolis. Spearman and Tobey Kendall correlation coefficients were used to investigate the significant relationship between variables. Also, regression was used for intensity of component effects.

    Results and discussion

    According to the results, all indicators (education and awareness, knowledge and skills and human resource development, competence, meaningfulness, self-determination, trust and confidence, participation) were significant. In fact, empowerment-enhancing indicators are below average. Indicators considered in the planning process are empowerment of local stakeholders, components of education and awareness, knowledge and skills that have an impact on sustainable rural development. Other indicators were excluded because their correlation was not significant and were at lower levels from the regression model. Between the two components of empowerment in the planning process with development, there is a correlation of 0.335. Finally, based on the standardized coefficient, the results show that education and awareness under the current conditions have the greatest impact on sustainable rural development. At present, the indicators of competence, meaningfulness, self-determination, trust and confidence, participation, institutionalism have not found their place in explaining sustainable rural development.

    Conclusion

    The implications of the current approach in environmental - ecological dimension do not improve land, quantity and quality of agricultural land, reduced erosion and soil quality, status of surface and ground water and quantity and quality of water, status of sewage system and waste collection. The social dimension doesn’t improve rural poverty alleviation, reducing vulnerability, rural efficiency, bank savings rates, and income levels in rural areas. In the economic aspect, public health, rural social security, quality of life through opportunities for education, education, services, quality of employment and income generation, rural housing renovation, rural migration, rural community status, cultural and artistic activities in the area are not improved. But in terms of physical, improvements, rural housing and rural access to infrastructure, markets for trading products, commercial and educational uses and the status of rural passages have increased.

    Keywords: Empowerment, Rural development, Pakdasht, Rey counties, Instrumental-technical planning approach
  • Ahmad Aryafar*, vahid Khosravi, Mohammad Amin Farshadmehr, Saeed Yousefi Pages 127-142
    Introduction 

    One of the main challenges about geochemical exploration is the selection of an appropriate method for anomaly separation from background. In this field, many approaches including statistical methods, artificial intelligence, soft computing and compositional methods have been developed. Each method has some weak and strong points. Research literature showed the statistical hybrid models were used less in this field.

    Materials and Methods

    Nowadays, the hybrid models have been considered to enhance the intensity of geochemical anomalies. Until now, only some hybrid models were used. The most important of them are neuro-fuzzy and genetic algorithm model, multifractal-neural network model, fractal-U statistic model, fractal-wavelet model and factor analysis-neural network model. The previous studies indicate that the univariate and multivariate statistic methods and artificial neural networks were mainly used as hybrid model. The main goal of this research is the identification of mineral potential of Au, Sb and As in Basiran 1:100000 sheet, which is located in 180 Km of West of Birjand, through using factor-fractal hybrid model. For this purpose, the 585-stream sediment geochemical data, which were taken by Trade, Mine and Industry Organization of South Khorasan, were analyzed for 20 elements including of Sb, As, Au, Ba, Se, Mn, Ti, Cr, Zn, Cu, Fe, Co, Ag, Sn, Mo, Ni, Pb, W, Hg and Bi.

    Results and Discussion

    In first step, the data have been studied by R-mode factor analysis and 5 factors were extracted. With respect to the goal, the third factor with the best linear combination of Sb, Au and As elements, was elected. Afterwards, the factor scores were calculated and depicted on the map of factor’s scores. Consequently, fractal method was applied on the concentration area based on third factor scores, and the thresholds values were determined. Finally, based on threshold values, the map of hybrid factor-fractal model was illustrated. Comparison of both obtained results using hybrid model and concentration-area fractal model indicated that the hybrid model is more effective. As indicated in the following figure, the position of heavy metal samples are located on identified mineralized zone using factor-fractal hybrid model.

    Conclusion

    In this paper, recognition of mineral potential of Au, As and Sb using factor-fractal hybrid model, is a new idea and innovation. For validation of hybrid model results, 6 heavy metal samples were gained and studied. The results of heavy metal studies confirmed the existence of gold particles in samples. The drawn results stated a good agreement (more than 90 percent) between heavy metal locations and identified mineral potential area by using the hybrid model.

    Keywords: Basiran, South Khorasan, Stream sediment, Regional geochemistry, Factor-fractal hybrid model
  • masoome eghbali*, Bahaedin Hamdi, Mahmoud Reza Majidifard Pages 143-158
    Introduction

    The study area is located in the zone of Central Iran based on the structural divisions of Iran. Late Devonian deposits in central Iran are widespread. The Shishtu Formation is a two-stroke stratigraphic unit that is subdivided into two sub-formations called Shishtu 1 and Shishtu 2. Below the Shishtu 1 Formation is the Late Devonian (Frasnian-Famenian) and the Shishtu 2 Formation is early Carboniferous (Tournisian-Visean). The boundary between them is marked by a horizon of black charcoal shales called the Mouse horizon. The Paleozoic and Lower Triassic sediments in the Lut Zone are essentially similar to the Shotori Mountain Formations.

    Materials and Methods

    Howz-e-Dorah section is located 57 km from Tabas town and 5 km from Deyhok village. After conducting library studies and selecting the appropriate shear in terms of thickness and separation of layers, the tectonic status of the area and the intended purpose by measuring layer thickness, fossil record collection, photography and sampling, extraction was conducted to extract the conodont elements.

    Results and Discussion

    The Shishtu Formation 1 is exposed at a thickness of 152 m in the Howz-e-Dorah section. The lower boundary of this sequence with the Bahram Formation is in disconformity with Middle Devonian and its upper boundary is in conformity with the Shishtu 2 Formation. Lithology of the Shishtu Formation 1 alternates from medium to thick bedded brown sandstones, green shales and thin bedded dolomitic white limestones, thin to thick bedded gray limestones, and highly diverse masses. It is high in conodont microfossils and macrofossils such as brachiopods, bryzoas, corals and crinoids. Notable points in this section are the presence of coral limestones, especially brachiopods, which are of late Devonian age in central Iran. The uppermost and last rock unit of the studied section is a 28 m outcrop of cephalopod horizon, outcropped as intermediate red limestone, indicating a short period of no sedimentation. Based on conodonts element studies, the sequence of late Shishtu Formation 1 to Late Devonian (Early Frasnian - Late Feminine) introduces 4 genus, 13 species, 4 subspecies with 4 conodonts biozonesThe anterior part of Shishtu 2 Formation ages back to Late Tournisian - Late Visean. 6 genus, 13 species, 4 subspecies, 13 species and 2 subspecies were identified in Howz-e-Dorah section. According to the studied conodonts elements, the sedimentary environment of the studied section is shallow and close to shore, and the conodonts species in the Shishtu 2 Formation are formed in oxygen and continental slope environments.

    Conclusion

    The study of Shishtu Formation 1 and the basal part of Shishtu Formation 2 resulted in the identification of a high diversity of conodonts in the Howz-e-Dorah section. In addition to the high diversity of conodonts, the diversity of invertebrates, especially brachiopods, has been very high. Depending on the biofacies, depth and depositional environment of the Shishtu Formation 1, due to biofacies, the environment was offshore. Also, the presence of conodonts species is characteristic of tidal environments in Shishtu 1 Formation. The base part of Shishtu 2 is formed in low oxygen environments which are common in lower continental slopes.

    Keywords: Howz-e-Dorah section_Late Devonian_Shishtu 1 Formations_Conodont_Frasnian-Famennian
  • Mahin Farhadian Babadi*, Behzad Mehrabi, Franco Tassi, Michael Zelenski, Ilya Chaplygin, Ata Shakeri, Stefania Venturi Pages 159-174
    Introduction

    Mud volcanoes or sedimentary volcanoes, represent one of the most intriguing phenomena of the Earth's crust. They are important for energy resource exploration, seismicity, geo-hazard and atmospheric budget of greenhouse gases. These structures are surface expressions of fluids including gas, water and mud inside hydrocarbon-bearing sedimentary basins. The discharged gas is typically dominated by methane, however where hydrocarbon systems are located close to subducting slabs, relatively high geothermal gradient environments or are related to the final stages of thermogenic gas generation, the gas can be mainly CO2 or N2. The Pirgel mud volcanoes, are the largest Iranian mud volcanos, located between Taftan and Bazman volcanoes.

    Materials and methods

    During this study, twelve gas samples were collected from all gas emitting points including pool, gryphon and cone using Giggenbach-alkaline solution in order to evaluate the hydrocarbon and non-hydrocarbon gas sources. The molecular composition of gas consisting methane and heavier hydrocarbon derivatives, CO2, O2, N2, He, Ar and He, carbon isotopic composition of methane and CO2 and He isotopic signature were determined by using GC and GC-MS methods, respectively.

    Results and discussion

    The gases emitted by Pirgel mud volcano are CO2-rich ranging from 83.9 to 88.7 vol. %. The other gas components are CH4 (9.31-12.90 vol. %), N2 (1.28-2.08 vol. %), C2H6 (0.43-0.54 vol. %), C3H8 (0.051-0.098 vol. %), iC4H10 (0.027-0.052 vol. %), nC4H10 (0.016-0.024 vol. %), O2 (0.088-0.180 vol. %), Ar (0.028-0.050 vol. %), He (77.76-111.77 ppm) and Ne (0.44-5.41 ppm). Carbon dioxide in CO2-richgas reservoirs is produced by a variety of organic and inorganic processes. Different CO2 sources can be recognized based on the 13C/12C ratios: 0‰ vs. V-PDB, <−20‰ vs. V-PDB and −6.5 ± 2.5‰ vs. V-PDB for marine limestone, alteration of organic material and Mid-Oceanic Ridge Basalts (MORB), respectively. At a first approximation, the δ13C-CO2 values measured in the CO2-rich Pirgel gases (from −11.9 to −13.8‰ vs. V-PDB) are intermediate between those typical of mantle and a biogenic source. The R/Ra values of these gases are ∼1.6 R/Ra, with low air contamination as indicated by the high He/Ne ratios (14–257). The contribution of upper mantle, as a probable source for discharged gas from Pirgel mud volcano is likely linked to geothermal fluids of nearby volcanic systems which is documented by 3He/4He isotopic ratio of ∼1.61 R/Ra. The CO2/3He ratios, ranging from 20×109 to 30×109, i.e. slightly higher than that typically measured for MORB (2×109–1×1010), coupled with the above mentioned δ13C-CO2 values, suggest that the origin of the CO2 discharged from Pirgel mud volcano is related to both biogenic and volcanic sources. The hydrocarbon gases are thermogenic in origin, evidenced by low methane to heavier hydrocarbon components (C1/C2+) ratio and δ13CCH4 valuesfrom -40.7 to -42.2 ‰. The presence of thermogenic gases are likely related to thermal degradation of organic matters in response to the existence of thermal processes or heat sources.

    Conclusion

    Pirgel mud volcano emits gases dominated by CO2 and shows relatively high R/Ra values (∼1.6). Gas geochemistry shows that the CO2-rich gases characterizing this mud volcano probably originated from both thermal degradation of sedimentary organics and hydrothermal fluids from the neighboring volcanic complex. The area probably hosts the hydrocarbon systems testified by the presence of thermogenic gases and dark oil appearance slicks in Pirgel mud volcano.

    Keywords: Helium isotopes, Carbon dioxide, Hydrocarbon, non-hydrocarbon gases, Pirgel mud volcano
  • maryam kiaeshkevaryan*, ali asghar Calagari, Ali Abedini, Gholam hossein Shamanian Pages 175-192
    Introduction

    The Separdeh laterite deposit in the western part of Alborz is about 114 km from the Ramsar city in Mazandaran province. This deposit is located between Triassic limestones (Elika Formation) and Jurassic sandstones (Shemshak Formation). There has been no comprehensive study on the Separdeh deposit. Only studies included 1: 100,000 scale geological map of Javaherdeh and identification of bauxite-laterite and refractory materials of Gilan province by Geological Survey of Iran. Therefore, this paper attempts to study the physicochemical conditions of formation, factors of ore type development and factors affecting the distribution, mobility and differentiation of rare earth elements, Ce and Eu anomalies, and determining the origin of the ore, taking into account the petrographic, mineralogical and geochemical features of the Separdeh deposit.

    Materials and methods

    Based on detailed field observations, 14 ore samples were systematically taken. These were perpendicular to the profile, picked up from the lateritic rocks due to changes in color, texture, and hardness. Thin sections were prepared for textural studies and X-ray diffraction (XRD) analyses of the samples for mineralogical studies at the Iranian Mineral Processing Research Center in Karaj. Geochemical studies of 10 samples were analyzed by ICP-OES and ICP-MS methods to determine the quantities of major and minor earth elements by MS Analytical Company in Canada.

    Results and Discussion

    Structural and textural studies in the Separdeh deposit indicate both autochthonous and allochthonous origins for this deposit. Mineralogical investigations revealed that minerals such as siderite, chamosite, kaolinite, boehmite, diaspore, hematite, goethite, clinochlore, and anatase are the main mineral phases accompanied by of minor phase like rutile, moscovite, and lipidocrocite. This mineral assemblage suggests that both underground waters with reducing-alkaline nature and surface waters with oxidizing-acidic nature played an important role in development of this deposit. Based upon chemical analyses, REE values of the ores vary from 58.91 to 846.72 ppm. Values of La/Y, Eu/Eu*, and Ce/Ce* of the ores are within the range of 0.34-3.76, 0.76-1.24, and 0.92-2.41, respectively. Geochemical studies showed that changes in the physico-chemical conditions of formation environment (pH and Eh), carbonate bed rock as a geochemical barrier, complexation with carbonate ligands, difference in the stability of minerals carrying rare earth elements (REEs), and fixation in neomorph phases, play important roles in distribution and mobility of REEs during the formation and evolution of the lateritic horizon at Separdeh. In addition, the Eu anomalies along with ratios of TiO2/Al2O3 and Sm/Nd indicate that upper Triassic rocks with andesitic to basaltic composition could be the potential precursor for this deposit.

    Conclusion

    Textural, mineralogical and geochemical studies show that the Separdeh deposit is formed in two stages. In the first stage, authigenic lateritization of the upper Triassic basaltic rocks has occurred, such as alteration and decomposing of silicate minerals and formation of clay, iron and titanium minerals. In the second stage, the transfer of lateritic material into karstic cavities and deposition in lagoon and swampy environments was carried out. These conditions have resulted in the formation of minerals such as pyrite, siderite, and facilitated the process of leaching of rare earth elements from the upper parts of the profile and deposited on the lower parts of the Separdeh deposit.

    Keywords: Rare earth elements, Mineralogy, Laterite, Separdeh, Eshkevarat
  • Babak Samani*, Adel Saki, Sahar Taghizadeh Pages 193-208
    Introduction

    Strain analysis in the deformed area has been one of the interesting subjects for structural geologist in the last decades. Strain studies based on field data help geologists to understand the parameters such as quantities of amounts of strain in the principal plane of strain ellipsoid, orientation of principal axes of strain ellipsoid, strain ellipsoid shape and the strain type. In this research the strain analysis of andalusite schist has been conducted in the south eastern part of Hamedan.

    Materials and methods

    In this research because of evolution of penetrative planar and linear structures in the andalusite schist rocks of south eastern part of Hamedan, these rocks have been studied as strain markers for strain analysis goals. The orientations of principal axes of strain ellipsoid and geometry of surface of non-finite longitudinal strains have been studied with application of stereography analysis and using structural elements. The geometry of surface of non-finite longitudinal strains was used as criterion for determination of amounts of finite strain in the principal plane of strain ellipsoid. Also with application of some graphical functions and the strain ratio in the principal plane of strain ellipsoid the amounts of kinematic vorticity number and the percentage of each pure shear and simple shear component were determined.

    Results and discussion

    Micro-tectonics and petrofabric studies show the development of three planar and two linear structural elements in the study area. S-C shear bands, delta and sigma types porphyroclasts, strain shadow and hat shadow are the most important structures that developed in the study area. These studies reveal the occurrence of two main deformation phases in the area. Using structural elements and application of stereography analysis of the planar and linear structures in the SpheriStat 2.2 software, the average pole of foliations and the lineation directions were determined as spatial locations of Z and X axis of strain ellipsoid. Therefore the direction of principal axes of strain ellipsoid in the first deformation phase were determined as X= 184/16, Y= 88/3, Z= 350/76 and the direction of principal axes of strain ellipsoid in the second deformation phase were determined as X=195/20, Y=345/59, Z= 95/12 respectively. Using of angular amounts of surface of non-finite longitudinal strain respecting the orientation of principal axes of strain ellipsoid and application of nomogram (Imber et al, 2012) of the amounts of finite strain in the XY and XZ principal planes of strain ellipsoid for both deformation phases were determined. The amounts of kinematic vorticity number for the first and second phase of deformation were calculated as 0.91 and 0.93 respectively. These results show the simple shear dominant deformation in both deformation phases.

    Conclusion 

    Results of strain analysis show the different strain ellipsoid shapes and orientation of principal axes of strain ellipsoid for each of deformation phases. Different amounts of strain parameters reveal the different effect of strain components in D1 and D2 deformation phases. Results of this research show the existence of inclined transpression in the Sanandaj-Sirjan zone as offered by previous geologist researchers. Probably the intrusion of Alvand batholiths causes local changes in the stress and strain properties and the high amounts of kinematic vorticity numbers causes simple shear dominant deformation.

    Keywords: Strain ellipsoid, Finite strain, Kinematic vorticity number, Surface of no finite longitudinal strain
  • Hamid Reza Nassery, Marzieh Saedy*, Farshad Alijani, Sadegh Alimoradi Pages 209-224
    Introduction

    In countries such as Iran that are facing a shortage of water resources, paying attention to all water resources is of the utmost importance. Until recently, drainage management had received less attention and more drainage research focused on design issues. Following the 1992 World Summits, the International Committee on Irrigation and Drainage focused its attention on drainage management and emphasized the conservation and use of fresh-water resources in the context of comprehensive water management. Many studies have been conducted about the effects of high water levels in different aquifers. The study of the role and seasonal contribution of the drain in the hydrology of the region (King et al., 2014.) is among these studies. Nowadays, the underground drain is used to lower the water level. Among the studies in this regard, the effect of drainage system on lowering of groundwater level of Shiraz plain using groundwater model by Karimipour et al can be mentioned. (2012).

    Materials and methods 

    Farrokhabad plain in Dehloran is classified as folded Zagros based on the division of Iranian building units (Nabavi, 1977). Shallow water levels in the village of Farrokhabad (five kilometers southwest of Dehloran) have caused problems for the inhabitants of the village, demanding the village to move to other areas. In this study, the use of drainage system for lowering groundwater level of Farrokhabad plain is evaluated. In this regard, the hydraulic behavior of the aquifer of Farrokhabad plain was modeled using Visual MODFLOW code. After calibration and validation, the model of impact of drainage system on groundwater status of Dehloran plain was simulated under three different scenarios. Scenario One: Lowering the plain water level by underground drainage in dry, wet and normal hydrological conditions for a five-year period. Scenario 2: Lowering the plain water level by using pumping wells in dry, wet and normal hydrological conditions for a five-year period. Scenario 3: Water table drop in different hydrological periods without drainage.

    Discussion and Results

    The drainage system used in the first scenario includes a combination of the main collection drains with the gradient at the point of the Meymah River, where drainage discharges. Due to the curves of the water table level in the drainage range, the water level drop over five years in dry climatic conditions is about two to four meters, in wet hydrological conditions four to five meters, and in normal hydrological conditions. There are four to five meters of drainage area available. Then, a series of pumping wells were used to lower the water level, considering the potential curves in the range of pumping wells in arid climatic conditions, with a water level of about three to five meters during the normal five years. In five-year period with wet hydrological conditions, three to five and a half meters drop and in dry hydrological conditions a drop of three to five meters in the range of pumping wells were observed.

    Conclusion 

    The results of the potential curves show better performance of wells than in the drain. However considering that the wells should be made to remove the water collected in them as well as transporting the water to other places, it requires more expenditures to drop the water level in this area. But with the proper design of the underground drain network, water can be transferred with gravity force to the Meymah river, and only the initial expenditure of the drainage is required. Though, with the proper design of the underground drainages, and the use of a layer of sand and coarse aggregate particles over the main branches of the drain can be used for several years. So with regard to the mentioned cases, it is more suitable to study the design of underground drainage wells. To lower the groundwater level to the desired depth, sub-drainage networks should be implemented in the direction of the land slope.

    Keywords: Groundwater, Farokh abad plain, Underground drainage, Simulation, Visual MODFLOW
  • Bahman Rahimzadeh* Pages 225-246
    Introduction 

    Dehgolan region is located in the northwest of Iran. In geological classification it is a part of the Sanandaj-Sirjan zone. In this region, several intermediate to acidic volcanic rocks with Upper Miocene-Pliocene age are outcropped such as Sheida- Akhikamal and Kaniderezh. The volcanic rocks from this region rocks are mainly andesite, trachy andesite and dacite. White to gray dacitic ash has been thrown around the outcrops have pozzolanic functon. Main phenocrysts are plagioclase, hornblende and biotite. Clinopyroxene with a very low frequency is also detectable in phenocrysts. In this research, mineral chemistry is used in order to investigate kinetic of the crystallization and genesis of rock forming minerals.

    Materials and methods

    In this study, after field sampling and preparation of thin sections and petrographic of the samples, in order to study the chemical composition of the minerals of plagioclase, amphibole, clinopiroxen and biotite minerals in Dehgolan volcanic rocks, Eleven samples of the freshest rocks were selected for EMPA point analysis and about 80 points of four types of minerals were analyzed.

    Results and discussion

    The results of the EPMA analysis of minerals indicate that plagioclases have a composition of andesine to oligoclase, Most have polysynthetic macles and also zoning is present. Their zoning is mostly normal, with the calcium content decreasing from core to rim. The amphiboles of the study area are calcic (calcium-rich and titanium-rich) and mainly of edenitic hornblende and magnesiohornblende types. Clinopyroxene are of augite type and based on clinopyroxene data, most of the samples in the study area are in the volcanic arcs (VAB) and (WPA). Biotites are Mg-biotite and are mostly of primary magmatic type and located between phlogopite and annite poles. The magma oxygen fugacity was high during the magma crystallization. Based on biotite composition, the Dehgolan volcanic samples belong to calc-alkaline magmatic assemblages of the orogenic environment. Clinopyroxenes in intermediate-acidic volcanic rocks in Dehgolan region show mainly crystallization at medium pressures and crystallize on average at 5 to 6 kb at temperatures of about 1000 to 1110 ° C, amphibole crystalized at 4 to 6 kb and 723 to 861 °C respectively. While the estimated temperature for plagioclase is between 550 to 750 °C and for biotite this is 715°C.

    Conclusion

    Volcanic rocks north of Dehgolan have a predominantly riodasite and sometimes andesitic composition with Calc-Alkaline nature, which erupts with large volumes of acid ash. The magma of the Adakitic rocks in northern Dehgolan was dehydrated during its formation, and only high-temperature, water-free minerals such as pyroxene and plagioclase were crystallized. In the following or on higher horizons collision with water in the crust iccurs and the crust is contaminated. The preponderance of xenolite confirms this, Oxygen fugitives are rised and biotite and amphibole minerals are crystallized. The biotite and clinopyroxenes geochemistry is indicative of the Calc-Alkaline Magmatic nature of the region, which erupted in the periphery of the active continental margin at the last phases of neotethys subduction in the northern Sanandaj-Sirjan region during the Mio Pliocene.

    Keywords: Adakite, Thermobarometry, Dehgolan, Sanandaj-Sirjan, Mineral chemistry