فهرست مطالب

پژوهش های چینه نگاری و رسوب شناسی - سال سی و یکم شماره 3 (پیاپی 60، پاییز 1394)
  • سال سی و یکم شماره 3 (پیاپی 60، پاییز 1394)
  • تاریخ انتشار: 1394/07/30
  • تعداد عناوین: 6
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  • مهدی دارایی *، عبدالحسین امینی، محمد صدیق، عباسعلی نیک اندیش صفحات 1-18
    این مطالعه به نقش فرایندهای رسوبی و دیاژنزی در کنترل کیفیت مخزنی سازند آسماری در یکی از میادین فروافتادگی دزفول، جایی که عضو ماسه سنگی اهواز گسترش قابل توجهی داشته و به سازند ویژگی مختلط (کربناتی- آواری) داده است، می پردازد. بدین منظور، از داده های رسوب شناسی و پتروفیزیکی دو چاه در میدان مذکور استفاده شده است و برای درک بهتر نقش تغییرات محیطی و دیاژنزی، از داده های 6 برش سطح الارضی واقع در شمال غرب زاگرس نیز استفاده گردیده است. بر اساس یافته های این مطالعه، کیفیت مخزنی سازند آسماری در بخش آواری میدان مذکور، توسط شرایط محیطی، به ویژه تغییرات رخساره ای و در بخش کربناتی، توسط فاکتورهای دیاژنزی، به ویژه دولومیتی شدن، انحلال و سیمانی شدن سولفاتی کنترل شده است. به صورت کلی، سازند آسماری در بخش کربناتی خود به دلیل تخلخل های قالبی و حفره ای حاصل از انحلال، دارای ظرفیت ذخیره بالایی است ولی ظرفیت جریان تنها در صورت وجود شکستگی ها افزایش یافته است. مهم ترین فرایند کاهنده تخلخل و تراوایی نیز در این میدان، سیمانی شدن سولفاتی تشخیص داده شده است که به ویژه اثرات آن در رخساره اائیدی متعلق به زیر محیط سد قابل ملاحظه است.
    کلیدواژگان: سازند آسماری، فروافتادگی دزفول، عضو ماسه سنگی اهواز، دیاژنز، کیفیت مخزنی
  • عباس صادقی *، قمرناز دارابی صفحات 19-36
    به منظور مطالعه، بایوسترا تیگرفی سازندگورپی در چاه های شماره 45، 21، 43، 123، 41 میدان نفتی مارون 525 مقطع نازک مورد مطالعه قرار گرفته است. ضخامت سازند گورپی در این چاه ها به ترتیب 181، 186، 194، 197،222 متر و لیتولوژی عمده آن شامل مارن، مارن آهکی، شیل، آهک شیلی و آهک می باشد. مرز زیرین سازند گورپی با سازند ایلام به صورت هم شیب و مرز بالایی آن باسازند پابده به صورت ناپیوسته همراه با یک نبود چینه شناسی در طول پالئوسن می باشد. در این مطالعه ضمن تشخیص 54 گونه متعلق به 18جنس از فرامینیفرها 8 بایوزون در چاه های مذکور شناسایی و معرفی شده است. سن سازند گورپی در چاه های مورد مطالعه بر اساس بایوزون های شناسائی شده سانتونین پسین تا مایسریشن پسین معرفی شده است. مطالعه سازند گورپی در چاه های مورد مطالعه (سانتونین پسین تاماستریشین پسین) و مقایسه آن با برش تیپ (کامپانین پیشین تا تا ماستریشن پسین) نشان می دهد رسوب گذاری سازند گورپی در چاه های مورد مطالعه در میدان نفتی مارون زودتر صورت گرفته است.
    کلیدواژگان: سازند گورپی، فرامینیفر های پلانکتون، بایوستراتیگرافی، میدان نفتی مارون
  • ئارام بایت گل *، رضا موسوی حرمی، اسدالله محبوبی صفحات 37-68
    سازند شیرگشت در بلوک کلمرد در ایران مرکزی به طور غالب از نهشته های کربناته و سیلیسی آواری تشکیل و در محیط های رسوبی متنوعی از پهنه های جزر و مدی، لاگون، حاشیه ساحلی- سد، دور از ساحل- شلف و رمپ کربناته ته نشین شده است. با توجه به خصوصیات رخساره ای، طرح برانبارش، شکل هندسی لایه ها، توالی آواری موجود به 5 مجموعه آواری شامل پهنه های جزر و مدی (FA1)، لاگون/ مخروط های شسته شده (FA2)، حاشیه ساحلی بالایی- پیش ساحل (FA3)، حاشیه ساحلی میانی- پایینی (FA4) و دور از ساحل شلف (FA5) و 4 کمربند رخساره ای کربناته شامل کمربند رخساره ای پهنه ای جزر و مدی (FA)، لاگون (FB)، سدی (FC) و دریای باز (FD) تفکیک می شود. چهار سکانس رسوبی در نهشته های رسوبی سازند شیرگشت بر اساس طرح برانبارش رخساره ای و سطوح اصلی چینه نگاری شناسایی شده است. طرح برانبارش رخساره ها در این سازند حاصل ارتباط متقابل بین تکتونیک ناحیه حاصل از گسل پی سنگ کلمرد و تغییرات جهانی سطح آب دریا در طول اردویسین است. سازند شیرگشت از دسته رخساره های گستره تراز پیشرونده و پسرونده تشکیل شده است که در نتیجه تاثیرات تکتونیکی حاصل از گسل پی سنگ کلمرد ایجاد شده است. فعالیت گسل کلمرد در این سازند به صورت تغییر در دسته رخساره ها، طرح برانبارش رخساره ای و سطوح چینه شناسی سکانسی نشان داده شده است.
    کلیدواژگان: محیط رسوبی، چینه نگاری سکانسی، سازند شیرگشت، اردویسین، گسل کلمرد
  • حسین کاظمی *، ابراهیم قاسمی نژاد صفحات 69-82
    سازند سنگانه یکی از واحدهای سنگی کرتاسه تحتانی حوضه رسوب گذاری کپه داغ در شمال شرقی ایران می باشد. این سازند در برش قلعه جوق به طور عمده از شیل های آهکی و شیل همراه با سیلتستون و میان لایه هایی از آهک و آهک های شیلی تشکیل شده است. سازند سنگانه به طور هم شیب در زیر سازند آتامیر و بر روی سازند سرچشمه قرارگرفته است. سن سازند سنگانه در برش مربوطه بر اساس مجموعه پالینومورف های شناسایی شده، آپتین بالایی- آلبین زیرین تعیین شده است. با مطالعه خرده مواد ارگانیکی موجود در اسلایدهای پالینولوژیکی، این مواد به سه گروه اصلی فیتوکلاست ها (Phytoclasts) یا پالینوماسرال (Palynomacerals)، پالینومورف های دریایی (Marine Palynomorphs) و مواد ارگانیکی بی شکل (Amorphous Organic Matters) تقسیم گردید و چهار رخساره پالینولوژیکی: II:Marginal basin III:Proximal shelf، IV:Shelf to basin transition، V:Distal shelf، برای سازند شناسایی شد. با استفاده از نتایج پالینوفاسیس یک جایگاه رسوب گذاری کم عمق تا نسبتا عمیق و تحت شرایط نیمه احیایی تا احیایی ضعیف (suboxic - dysoxic) برای انباش سازند در این برش پیشنهاد گردید. در تفسیر محیط دیرینه با استفاده از نمودار مثلثی پالینومورف، محیط رسوبی سازند سنگانه از دریایی کم عمق تا محیط نسبتا عمیق پیشنهاد می شود. همین طور با بررسی نسبت های مواد ارگانیکی با هم دیگر برای هر نمونه و با تلفیق داده های به دست آمده به منظور تحلیل نوسانات سطح آب و تفکیک واحدهای سکانسی، سه سکانس رسوبی با مرزهای آن برای سازند سنگانه تفکیک گردید.
    کلیدواژگان: برش قلعه جوق، چینه نگاری سکانسی، پالینوفاسیس، سازند سنگانه، کپه داغ، مواد ارگانیکی، محیط دیرینه
  • نرگس هاشمی *، علیرضا عاشوری، منصور علی آبادیان صفحات 83-94
    مطالعه بقایای ریز مهره داران مناطق شرقی ایران با توجه به رسوبات کواترنر کمتر و تفاوت جغرافیای زیستی آنها با نواحی غربی و شمال غربی ایران از اهمیت ویژه ای برخوردار است. مطالعه دیرینه جغرافیای زیستی و بررسی تغییرات اقلیمی کواترنر بر روی مجموعه های جانوری شرق و شمال شرق ایران منجر به شناسایی بقایای استخوانی و دندانی گونه Tatera indica از رسوبات اواسط تا اواخر هولوسن نواحی کنار صندل جیرفت (اوایل هولوسن) و تپه نادری مشهد (اواخر هولوسن) گردید. یافتن این بقایا در ناحیه تپه نادری مشهد حاکی از تغییرات اقلیمی شدیدی در این بخش از کشور می باشد، زیرا این گونه در حال حاضر در مناطق شمال شرقی ایران یافت نمی شود و این در حالی است که تراکم بقایای یافت شده در جیرفت فراوان بود. این گونه نسبت به سرما بسیارحساس بوده و به جز سرما با سایر شرایط اکولوژیکی قابلیت سازش پذیری دارد. علاوه بر جیرفت، مدارک به دست آمده از زیای این جانور در سایر مناطق نیمه جنوبی کشور نشان می دهد که از حدود ده هزارسال پیش و از زمان آغار هولوسن تا کنون و همزمان با گرم شدن تدریجی هوا، تغییراتی در انتشار اصلی این گونه در این بخش از ایران به وجود نیامده است که این امر می تواند حاکی از پایداری و مقاوم بودن این جانوران به ویژه در برابر شرایط گرم باشد.
    کلیدواژگان: دیرینه جغرافیای زیستی، دیرینه اقلیم شناسی، کواترنر
  • محمد نبی گرگیج، آزاده بردبار *، مهدی نجفی صفحات 95-116
    نهشته های کرتاسه بالایی در شمال غرب نهبندان (برش بصیران) شامل کنگلومرا، تناوب کنگلومرا- ماسه سنگ، مارن با میان لایه هایی ازسنگ آهک - آهک ماسه ای و سنگ آهک متوسط لایه تا توده ای به ضخامت 275 متر است. مرز زیرین توالی مورد نظر با نهشته های ژوراسیک؟(تناوب ماسه سنگ و شیل) و در برخی مناطق با نهشته های کرتاسه زیرین به صورت فرسایشی (ناپیوسته) و مرز بالایی آن به طور دگر شیب به کنگلومرای پالئوسن- ائوسن ختم می شود. براساس ویژگی های پتروفابریک رسوب شناسی، شواهد صحرایی و همچنین فراوانی و توزیع فرامنیفرا و دیگر اجزا موجود در رخساره های مختلف، 9 ریزرخساره مربوط به کمربند های رخساره ای ساحل، پهنه جزر و مدی، لاگون، سد، دریای باز کم عمق و دریای باز عمیق تعیین شده است. تغییر تدریجی رخساره های آب های کم عمق، عدم وجود موجودات ریف ساز و کربنات های دوباره نهشته شده نشان می دهد که توالی کربناته برش بصیران در یک پلاتفرم کربناته از نوع رمپ هوموکلینال نهشته شده اند. مطالعات چینه نگاری سکانسی منجر به شناسایی 4 سکانس رسوبی در برش بصیران شده است. سکانس های شناسایی شده توسط مرز های سکانسی نوع 1 (مرز زیرین سکانس رسوبی اول و مرز بالایی سکانس رسوبی چهارم) و 2 از یکدیگر تفکیک می شوند. سکانس رسوبی اول در بردارنده دسته رخساره ای TST، LST و HST است. این سکانس شامل ریز رخساره های اینتراتایدال، لاگون، سد، دریای باز کم و دریای باز عمیق می باشد. مرز زیرین آن از نوع SB1 است. سکانس رسوبی دوم و سوم شامل دسته رخساره ای TST، HST و دربردارنده ریزرخساره های دریای باز کم عمق و سد می باشد. این سکانس ها توسط مرز سکانسی SB2 از یکدیگر جدا می شوند. سکانس رسوبی چهارم نیز در بردارنده دسته رخساره ای TST و HST است. مرز بالایی آن از نوع SB1 و با یک ناپیوستگی مشخص به کنگلومرای پالئوسن ختم می شود.
    کلیدواژگان: نهبندان، برش بصیران، ریزرخساره، چینه نگاری سکانسی، کرتاسه بالایی
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  • Mehdi Daraei *, Abdolhossein Amini, Mohammad Sedigh, Abas-Ali Nickandish Pages 1-18
  • Pages 19-36
    Introdaction: The Gurpi Formation is developed in the central of the Zagros fold in Khuzestan, Lorestan and Fars provinces of southwestern Iran, defined az theZagros basin, The Gurpi refers to Gurpi Mountain in the Kuzestan province.type section gurpi,which is N of the Lali oil wells and N-E of Masjed – Soleiman city,comprises 320m argillaceous limestone and gry-to-blueshale marl(James and Wynd,1965)Although the boundary the Gurpi Formation and the underlying Ilam Formation is reported to be gradual,the altered facies found at this boundrary could be a sign of a low disconformity or even unconformity.In some place,the Ilam Formation does not exist and tne Gurpi Formation lie abave the Sarvak Formation.The upper boundry of the Gurpi Formation is more noticeable and there are different overlying formations.In Khozstan province,the Gurpi Formation is overlain by purplr shale of pabdeh Formation with signs of unconformity.The Gurpi Formation is not always concurrent. Biostratigraphy and lithological characteries of the Gurpi Formation were studied by James and Wynd (1965), Taheri (1998), KameliAzao (2002), Zarei (2005), Hematinasab (2008), Madavian (2009), Tavalaian (2011). This research study aims at describing the biostratigraphy of Gurpi Formation.In this study five stratigraphic section is investigate for its Planktonc Foraminiforal content. Method and Matrials: This study involves five stratigraphic sections from the Gurpi Formation that were measured the ticknes and determind of Litostratigrapic limit as well as recognizd of detail litostrstigray the Gurpi Formation.More than 525 thine sections were examined. Some samples from the underlying Pabdeh Formation were also analysed for comparison. then recognizd Genus and species of Planktonic foraminifera and biozones mentioned wells have been introduced. In order to the biozonation of Gurpi Formation, stratigraphic distribution of well- known foraminifora is recognizd and then biozones are established through stratigraphic column. Discussion of Results &
    Conclusions
    In order to study biostratigraphy Gurpi Formation, in Wells numbers 45,21, 43, 123, 41of Marun Oil Field sections, 525 thin sections were studied. The thickness of Gurpi Formation in this Wells is 181, 186, 194, 197, 222 meters and its main lithology includes Marl, Limy Marl, Limestone and Shale. In all of the wells Lower boundary of Gurpi Formation is transition with Ilam Formation, and its upper boundary with Pabdeh Formation is unconformite accompanied by lack of stratigraphy in the length of Paleocene. In this study, alonge with recognition of 54 species belonging to 18 Genus of Planktonic foraminifera, 8 biozones mentioned wells have been introduced as follows. 1) Dicarinella asymetrica zone (Upper Santonian), 2) Globotruncanita elevata zone (Lower Campanian), 3Globotrnucana ventricosa zone (Middle Campanian), 4) Radotruncana calcarata zone (Upper Campanian), 5) Globltruncanella havanensis zone (Upper Campanian), 6) Globotruncana aegyptica zone (Uppermost Campanian), 7) Gansserina gansseri zone (Upper Companian- Lower Massrtistian), 8) Contusotruncana contusa zone (Middle to Upper Massrtistian) Based on the assemblage of foraminifer and determinate biozones, the age of Gurpi Formation in The examined wells are determined of Late Santonian to Late Maastrichtian. In this study, Gurpi Formation in of Marun Oil Field with Section samples in the region Lali (Khuzestan) has been compared and. show that the sedimentation of Gurpi Formation has been starte in Wells at Latest Santonian time, wile in the type section start at the Early Companian time.
    Keywords: Gurpi Formation, Planktonic Foraminifera, Biostratigraphy, Muron Oil Field
  • Aram Bayetgoll *, Reza Mousavi, Harami, Asadolah Mahboubi Pages 37-68
    Introduction
    Sedimentological and sequence stratigraphic analysis providing insight into the main relationships between sequence architecture and stacking pattern, syn/post-depositional tectonics, and eustatic sea-level fluctuations (Gawthorpe and Leeder 2000; Zecchin et al. 2003, 2004; Carpentier et al. 2007). Relative variations in sea level are due to tectonic activity and eustasy. The Shirgesht Formation in the Kalmard Block of Central Iran provides a useful case study for to determine the processes responsible on internal architecture and stacking pattern of depositional sequences in a half-graben basin. In the Shirgesht Formation, siliciclastic and carbonate successions of the Kalmard Basin, the cyclic stratigraphic record is the result of the complex interaction of regional uplift, eustasy, local tectonics, sediment supply, and sedimentary processes (Bayet-Goll 2009, 2014; Hosseini-Barzi and Bayet-Goll 2009).
    Material and Methods
    Lower Paleozoic successions in Tabas and Kalmard blocks from Central Iran share the faunal and floral characteristics with other Gondwana sectors such as south-western Europe and north Africa–Middle East (Ghaderi et al. 2009). The geology of these areas was outlined by Ruttner et al. (1968) and by Bruton et al. (2004). The Cambrian-Middle Triassic strata in the Kalmard Block were deposited in a shallow water platform that possesses lithologic dissimilarities with the Tabas area (Aghanabati 2004). The occurrence of two active faults indicates clearly that Kalmard basin formed a mobile zone throughout the Paleozoic so that lithostratigraphic units show considerably contrasting facies in comparison with Tabas basin (Hosseini-Barzi and Bayet-Goll 2009; Bayet-Goll 2014). The Shirgesht Formation in the Block Kalmard is mainly composed of carbonate-siliciclastic successions that disconformability overlain Kalmard Formation (attributed to Pre-Cambrian) and is underlain by Gachal (Carboniferous) or Rahdar (Devonian) Formations along the basement Kalmard Fault. In the present study, three stratigraphic sections (NW-SE transects) were measured, described and sampled in the Kalmard area. In these sections, detailed considerations have been given on the lithofacies variations; bed geometry and contacts, faunal content, the potential of trace fossils as tools for reconstructing depositional conditions, sedimentary textures and structures, bounding surfaces, vertical trends and stacking patterns and lateral/vertical variations in facies and thicknesses. The observed siliciclastic facies can readily be interpreted using existing shelf sedimentation and shoreline succession models (e.g. Walker and Plint 1992). Interpretation carbonate facies have been done on the basis the microfacies analysis (200 thin-sections), sedimentary textures and structures and faunal content (Wilson et al. 1975; Flügel 2010). In final, internal architecture, characteristics of sedimentary facies, the overall stacking pattern and nature of sequence-bounding unconformities have been investigated to evaluate the influence of regional uplift, local tectonics and eustasy on both along-strike variations in sequence architecture and genetic complexity of sequence boundaries. Discussion, Results and
    Conclusion
    The Lower Ordovician Shirgesht Formation in central Iran is composed of siliciclastic and carbonate rocks deposited in diverse coastal and marine shelf environments (tidal flat, lagoon, shoreface, and offshore-shelf and carbonate ramp). Relying on the facies characteristics and stratal geometries, the siliciclastic succession are divided into five facies associations, FA1 (tidal flat), FA2 (lagoon/washoverfan), FA3 (upper shoreface-foreshore), FA4 (lower to middle shoreface), and FA5 (offshore-shelf).Carbonate succession of this formation based on lithology, sedimentary characteristics and textures divided into four facies belts, FA (tidal flat), FB (lagoon),FC (shoal/barrier island), and FD (open marine). These facies associations are arranged in small-scale sedimentary cycles. These cycles reflect spatial differences in the reaction of the depositional system to small-scale relative sea-level changes. Systematic changes in stacking pattern of these cycles allow inferring long-term changes in sea-level (Bádenas et al. 2010; Bayet-Goll et al. 2014). The high-resolution sequence stratigraphic analysis of the shirgesht Formation displays the presence of four well-defined 3rd order depositional sequences (DS1–DS4). The stratigraphic architecture of the Shirgesht deposits is the result of the interplay between regional uplift and high amplitude, Ordovician glacio-eustatic sea level changes. The Shirgesht Formation is composed of transgressive and highstand systems tract couplets interpreted as reflecting fault-driven subsidence and the continuous creation of accommodation in the hangingwall to the Kalmard fault. Activity on the Kalmard fault led to marked spatial variability in stratal stacking patterns, systems tracts and key stratal surfaces. Constant and slow uplift of the NE/S basin around the Kalmard faults extends across the north and southeast portions of the study area explains the differential subsidence and the observed facies zonation of the mixed shelf siliciclastic-carbonate systems of the Shirgesht Formation. The correlation facies zonation also, suggests that the high bulk of the deeper siliciclastic deposits (DS1-2 and DS4) and the mid ramp limestone facies (DS3) in the NW basin representing enough accommodation space. Rapid subsidence typically leads to strong stratigraphic expansion and good preservation of thick 3rd order depositional sequences in the NW basin. The prominent lateral change in component units (systems tracts) and nature of bounding surfaces within the studied sequence seems to be directly related to the presence of faults and differential subsidence in along basin. Based on the above observations, such as set of high-angle faults and other basement structures, the Shirgesht Formation deposits in study area, was deposited on a half-graben sub-basin. This half-graben basin formed during Ordovician time by subsidence along the northwest-wards downthrowing and southeast-ward propagating Kalmard Fault. In final, it suggests that sequence architecture and nature of bounding surfaces reflects not only eustasy and sediment supply, but also local fault-controlled, short-term creation and loss of accommodation space.
    Keywords: Sedimentary environments, sequence stratigraphy, Shirgesht Formation, Ordovician, Kalmard fault
  • Hossein Kazemi *, Ebrahim Ghasemi, Nejad Pages 69-82
    Introduction
    Kopeh-Dagh basin is located northeast of Iran and in this basin the sedimentary beds began from middle Jurassic. The Sanghaneh Formation is one of the lower Cretaceous rock units in sections. One of the important fossils group are palynomorphs that described very abundant in this formation. Dinocysts diversity on this formation is more than other palynomorph groups. Palynological studies are done by keshmiry et al. (2014), davtalab et al. (2007) and etc. This formation here is laying on Sarcheshmeh Formation and is covered by Aitamir Formation. The age of this formation in the Qalehjegh section based on the dinoflagellate assemblage, is Late Aptian – Early Albian. Purpose of this research is palaeoenvironmental study base on palynofacies interprets and to separate sedimentary sequence Kopeh-Dagh sedimentary basin. Qalehjegh section is located between 57 ˚ 23 ’ 03” E and 37 ˚ 43 ’ 17” N. The formation comprises mainly calcareous shale and shale with siltstone and interlaminations of limestone and argillaceous limestone. The Sanghaneh Formation is studied base on several group of fossils in other using organic matter contents of the rock unit.
    Material and Methods
    For palaeoenvironmental and sequence stratigraphy purposes, 127 rock samples collected from the formation and prepared in the palynology laboratory.Standard preparation methods were used (Traverse 2007). Cold hydrochloric (30%) and hydrofluoric (30%) acids were used to dissolve carbonates and silicates. No oxidants or alkalis were used. The residue was neutralized and centrifuged in ZnCl2 (specific gravity 1.9), then sieved at 20 µm using a nylon mesh, and mounted on microscope slides using liquid Canada balsam and then the slides were examined in the transmittal microscope. Discussion of Results &
    Conclusions
    Palaeoenvironmental interpretation: Three main groups of sedimentary organic matter (SOM) can be distinguished: (1) amorphous organic matter (AOM), (2) phytoclasts including black and translucent matter and (3) palynomorphs including (dinocysts, acritarchs, foraminifera linings, spores and pollen grains). Compositional changes in palynofacies are useful in palaeoenvironmental interpretations of sedimentary rocks (Tyson, 1993). The results of all are plotted on an AOM– Phytoclasts–Palynomorphs ternary diagram after Tyson (1995). Studying Sanghaneh Formation in Qalehjegh section based on the three major groups of organic matter debris found in palynology slides (Palynomacerals or Phytoclasts, Marine Palynomorphs and Amorphous Organic Matters), four types of palynofacies were recognised: palynofacies II: Marginal basin, III: Proximal shelf, IV: Shelf to basin transition, V: Distal shelf. Pf1: This palynofacies is marked by an increase in phytoclasts content (65-90%) compared to palynofacies III and IV, and low frequency of marine palynomorphs (5-15%) and AOM (5-25%). AOM diluted by high phytoclast input, but AOM preservation moderates to good. Generally low AOM preservation. This facies was represented Marginal dysoxic - anoxic basin. It represents type II kerogen of Tyson. This palynofacies was recognised in samples 1058, 1053, 1040, 970, 963, 918, 907, 820, 808, 772, 762, 759, 750, 744, 4946, 4944, 4907, 4894 and 4892. Pf2: This facies is characterized by high phytoclasts (50-80%), low AOM (5-15 %) and common marine palynomorphs (15-45%). This facies was represented Heterolithic oxic shelf ("proximal shelf") and it was represented type III kerogen of Tyson (1993). This palynofacies was founded in samples 1036, 1012, 991, 987, 983, 978, 974, 952, 942, 931, 922, 910, 904, 899, 897, 885, 859, 841, 833, 830, 827, 816, 810, 791, 781, 766, 756, 5012, 5007, 5005, 5003, 5000, 4998, 4991, 4980, 4942, 4928, 4926, 4922, 4920, 4916, 4914, 4909, 4888, 4884, 4882, 4878, 4872 and 4870. Pf3: This is characterized by low marine palynomorphs (10-25%), 4-45% AOM and a predominance of phytoclasts 40-80% of the total particulate organic matter [POM]). The facies is proportionate with fourth palynofacies (IV) of Tyson (1993). This facies is represented Shelf to basin transition and it was recognised in samples 1061, 1042, 1032, 1028, 1027, 1017, 1004, 966, 950, 948, 945, 934, 881, 877, 874, 869, 855, 851, 845, 838, 813, 806, 802, 794, 774, 5016, 5014, 5010, 4994, 4989, 4975, 4966, 4948, 4940, 4932, 4924, 4918, 4912, 4898, 4896, 4890, 4886, 4880 and 4874. Pf4: This facies is characterized by a moderate to high abundance of Marine palynomorphs (30–70%), a moderate abundance of phytoclasts (20–45%) and a low to moderate abundance of AOM (5–30%). Rising of marine palynomorphs depends to offshore condition. The facies is proportionate with fifth palynofacies (IV) of Tyson (1993) and it represented distal shelf sedimentary environment. This palynofacies was founded in samples 1024, 1020, 1008, 955, 939, 894, 889, 879, 865, 788, 786, 4959, 4938, 4903 and 4901. Federova (1977) and Duringer & Doubinger (1985) have used plots of spores, pollen, and microplankton in a ternary diagram to indicate general depositional environments and associated regressive-transgressive trends. This ternary is considered here as a useful tool for recognizing and indicating the possible depositional environments and changes in trends of marine sedimentation. Based on this plot, sedimentary environment of Sanghaneh Formation recommended as from shallow marine (neritic) to offshore (moderately deep). Assimilating palynofacies with palynology plot data, sedimentary environment setting of the formation on Qalehjegh section is recommended shelf area and with a suboxic-dysoxic conditions. Separating sequences of the Sanghaneh Formation: One of approach in sequence stratigraphy is using from palaynologycal agents. In this study is used almost some agents of palynology to separate sequences. The palaynologycal agents used here is inclusive: phytoclacts percentage, opaque phytoclasts percentage, brown phytoclasts percentage, opaque to brown phytoclasts ratio, cubic to lath opaque phytoclasts ratio, AOM percentage, terrestrial palynomorphs absolute abundance, marine palynomorphs percentage and dinocysts diversity. In Transgressive System Tract (TST) is increased marine palynomorphs (Leckie et al. 1992), AOM (Tyson 1993), dinocysts diversity (Habib 1982) and lath opaque phytoclasts contents. In contrast in this systems tract phytoclasts contents (Tyson 1993) and terrestrial palynomorphs are decreased (e.g. Habib 1982). But from TST to Highstand System Tract (HST) is descended marine palynomorphs, AOM, dinocysts diversity and lath opaque phytoclasts contents and phytoclasts, terrestrial palynomorphs and cubic opaque phytoclasts contents is ascended. In sequence boundary brown phytoclasts content and terrestrial palynomorphs are abundant (Tyson 1993) and in maximum flooding surface (mfs) opaque phytoclasts contents and marine palynomorphs are most abundant (Habib 1982). Based on palynofacies analysis tree genetic stratigraphic sequences (A, B and C) w ere recognized. Genetic sequence A is extended until depth of 0-720 m. In this sequence TST started may be is part of the Sarcheshmeh Formation until depth of 350 m, and HST was begun from depth of 350-720 m. Genetic sequence B is bounded by the sequence boundary A (Sb1) and the sequence boundary B (Sb2). It is started form depth of 720-1350 m. HST and HST is placed from 720-1140 and 1140-1350 m. Genetic sequence C is bounded from down by the sequence boundary C (Sb3) and up boundary is not distinct.In this sequence TST is started from depth of 1350-1600 m and HST is started from 1600 m and continues to end of the formation. Studying the Sanghaneh Formation in Qalehjegh section based on the three major groups of organic matter debris found in palynology slides, four types of palynofacies were recognized: II, III, IV and V. According to palynofacies analysis, the formation depositional setting varies from shallow to moderately deep environment under suboxic-dysoxic conditions. In the interpreted palaeoenvironment using ternary palynomorph plot, it is recommended that sedimentary environment of the formation is shallow marine to offshore. Statistical studies on palynofacies factors and palynomorphs plot represent sedimentary environment setting of Sanghaneh Formation in Qalehjegh section as a shelf area with suboxic-dysoxic conditions. Similarly the stratigraphic analysis of palynofacies changes led to the separation of three sequences with their boundaries.
    Keywords: Qaleh jegh section, Kopeh, Dagh, Organic matters, Palynofacies, Palaeoenvironment, Sanghaneh Formetion, Sequence stratigraphy
  • Narges Hashemi *, Alireza Ashouri, Mansour Aliabadian Pages 83-94
    Introduction
    Study of quaternary microvertebrate remains in eastern Iran, according to a few of the sediments is very important. Reconstruction of quaternary climate in many parts of West and North West of Iran as the biggest karst state is possible, such as cave Kani Mikaiel (Hashemi et al. 2005, 2006, 2007a;b, 2008; 2010, Jangjoo et al. 2010), Yafteh cave (Otte et al. 2007, Hashemi et al. 2015). However, such studies were very poor in eastern and north-eastern Iran (Hashemi and darvish 2006; Hashemi et al. 2008, 2015). Investigation of taxonomic identification; quantification and distribution of micromammals revealed that these remains are useful in paleontology and archaeological research, because their abundance is useful for paleobiostratigraphy and dating of continental sediments. The recent research is about reconstruction of paleoclimate in two archeological sites of Konar sandal (KS) (Jiroft) and Tapeh Naderi (TN) (Mashhad) based on the microvertebrate and especially Tatera indica species. In these sites we attempted to solve the palaeoenvironment condition by analysis of rodent remains which hold the greatest potential to monitoring of ecological parameters (Hoover et al. 1977; Getz 1961; Reig 1970; Merritt 1974). Combining of a rich network of data with using of morphological and morphometric methods; reconstruction of paleoenvironment; documentation and investigation of their relationship with the environment is the main result of this research. Material & Methods; In both zooarchaeological samples which are composed of juveniles and young individual rodent, (KS, NISP=800 and TN, NISP=3) cranial and postcranial remains were sorted anatomically and washed with water. Dental pattern of mandible and maxillary tooth rows were drowns using a drawing tube connecting to a stereomicroscope (Olympus SZH-10). All recovered teeth fragments were measured based on the greatest dental length and width of the upper and lower jaw molars when possible, with the aid of measuring microscope having accuracy 0.001 mm. One of the main goals of the detailed analysis on dental remains is obtaining the changes of teeth size during time and space (Mashkour and Hashemi 2008). KS remains were recovered out by water sieving a column of three geological sieves with decreasing size of the mesh from top to bottom: 1 cm, 0.5 cm and 0.2 cm. Furthermore, all obtained information, which depending on the type of the skeletal remains has been entered in tables of excel for statistical analysis. Combination of morphometric with morphological studies and their identification keys were used to identify of the remains. Based on these methods, known examples in both archeological sites were belonging to Gerbillinae and Tatera indica species. Discussion of Results &
    Conclusions
    The effect of climate change on Tatera indica species was found for the first time in 1973 in the western regions of Iran and Dehloran plain (10,000-3800 years ago) (Redding 1978). This region has 200 to 399 mm of rainfall per year; rivers, streams, marshes and channels which represents wet conditions in most of the year. In this area, in addition of Tatera indica species, Nesokia indica, Mus musculus, Gerbillus nanus and Meriones crassus were identified. The remains of Tatera indica species with Nesokia and Mus were found also in Shahre shoukhteh in Sistan which wa s reported approximately 6000 years ago (Chaline and Helmer 1974). Presence of Tatera indica in KS site and also in other central, western, southwestern and eastern Iran during the mid to late Holocene can be show that climatic and environmental conditions in the southern half part of the country has not changed from 9000 years to recent (Alley et al. 1997). Finding the dental and cranial remains of Tatera indica in TN of Mashhad and in another archeological site such as Kohandejh in north east of Iran (Nishapur) can be indicate the change climate probably was intense in 2,000 years ago in this part of Iran, because recently, this species not found in northeast of Iran and the maximum their current geographical spread of this species is Torbat-e Jam, while density of these remains were very much in KS, 6000 years ago, (Jiroft).This species is very sensible to cold climate and except of this; it is adaptability with other ecological conditions (Misonne 1959). Addition to Jiroft, obtaining evidence from this remain fauna in other regions of half southern part of Iran showed that from about 10,000 years ago and ever since the Holocene started, with gradual warming of the weather, distribution of this species has not been changed in southern part of Iran, which would be indicative the stability of this species against to warm condition.
    Keywords: Paleobiogeographic, Paleoenvironment, Quaternary
  • Mohammad Nabi Gorgij, Azadeh Bordbar *, Mehdi Najafi Pages 95-116
    Introduction
    The Basiran stratigraphic section is located about 160 km northwest of Nehbandan.The section was measured in detail at 59 06 30 N and 31 52 50 E. Nehbandan area with respect to fourfold geological subdivision of Iran is part of Central Iran that is located in the eastern flank of Lut Block which first time are studied by Stocklin et al.in 1972. Gorgij (2001) stratigraphically and paleontologically investigate Upper Cretaceous deposits in Mighan and Basiran sections. Upper Cretaceous deposits in in this area consists of 275m conglomerate,alternation of conglomerate-sandstone, sandy limestone -marl and limy marl, marl with intercalation of limestone-sandy limestone thin beds and medium-bedded to massive limestone. Microfacies analysis led to the recognition of 9 microfacies that are related to 5 belts; Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. Main part of the section are deposited in the open marine environment that consist of marl,marly limestone and limestone. The doals of this study are: (1) describing and determining main carbonate and siliciclastic microfacies of late Cretaceous deposits (2) interpreting and providing depositional model for reconstruction of its paleoenvironmental setting based on microfacies characteristics (3) dividing the section based on lithostratigraphic principles and (4) recognizing a sequence stratigraphic model of this successions based on the vertical variation of facies,stratal key beds and stratal packing pattern.
    Material And Method
    The Basiran section as a complete stratigraphic section was measured and described. Up to 68 samples (indicated by KB1 to KB68) were collected and 170 thin sections are prepared. Based on field observations, sedimentological characteristics, parasequence stacking patterns, sequence boundary types and other key stratigraphical surfaces are identified and were obtained. Scheme of Dunham (1962) and Embry and Klovan (1971) for carbonate rocks and for samples descriptions from Flugel (2004) and Wilson (1974) methods were used. Discussion of Results and
    Conclusions
    The Basiran section predominantly composed of limestone - marl in the middle and upper part and conglomerate – sandstone in the lower part. The most prominent component of carbonate sediments are larger foraminifera such as Orbitoides, Lepidorbitiodes, Siderolites, Omphalocyclus and some of pelagic foraminiferas. Systematic determination of those benthic foraminiferas suggests Late Campanian-Maastrichtian age for Basiran section. Microfacies analysis led to the Recognition of 9 microfacies that are related to 5 belts; Coast, tidal flat, lagoon, shoal, shallow open marine and deep open marine environments. With respect to gradual shallow water facies changes, absence of barrier reef, sliding and slumping structure, cortoids, oncoids, pisoids and aggregate grains, that are abundant in rimmed shelves, several evidences shows that above mentioned carbonate are deposited in the ramp environment (Burchette & Wright 1992). Furthermore, based on high diversity and abundance of benthose foraminiferas this environment can be considered as foram dominated carbonate ramp system (Boxton & Pedley 1989). Based on field observation, microfacies analysis and sequence stratigraphic studies, fourth third order depositional sequence (DS) in the Basiran section are identified. These depositional sequences are separated by type1 sequence boundary (lower boundary of first depositional sequence and upper boundary of fourth depositional sequence) and type 2 sequence boundary (lower boundary of 2 nd and 3 rd depositional sequence). First depositional sequence consists of LST, TST and HST and contains tidal flat, lagoon, shoal, shallow open marine and deep open marine microfacies. Lower boundary is of type 1 sequence boundary (SB1). 2 nd and 3 rd depositional sequences consist of TST and HST. Therefore contains shallow open marine and shoal microfacies and have been separated by sequence boundary type 2 (SB2). Fourth depositional sequence contains of TST and HST. Upper boundary is of type 1 sequence boundary (SB1) and terminates to with clear unconformities to Paleocene conglomerate. It is seems that both local tectonic activity and global eustasy may have controlled the third and forth order sequences and cyclicities of the Upper Cretaceous sediments in Basiran section. The SB1 in the top of the fourth depositional sequence, which shows subaerially exposed the carbonate platform, possibly related to the widespread glacio-eustasy sea-level drop could be linked to the cooling event in the Cretaceous-Tertiary boundary(KTB).
    Keywords: Nehbandan, Basiran Section, Microfacies, Sequence stratigraphiy, Upper Cretaceous