-
دسترسی آزاد مقاله
1 - Sedimentological and provenance analysis of the Cretaceous Moro formation Rakhi Gorge, Eastern Sulaiman Range, Pakistan
Muhammad Khan Shahid Ghazi Mubashir Mehmood Abdollah Yazdi Abbas Ali Naseem Umair Serwar Arsalan Zaheer Hadayat UllahThe Cretaceous Moro Formation from the Rakhi Nala section Dera Ghazi Khan has been studied in detail to investigate the Sedimentology and provenance. This paper describes the litho-facies changes, depositional environment, and provenance analysis of the Cretaceous Moro چکیده کاملThe Cretaceous Moro Formation from the Rakhi Nala section Dera Ghazi Khan has been studied in detail to investigate the Sedimentology and provenance. This paper describes the litho-facies changes, depositional environment, and provenance analysis of the Cretaceous Moro Formation from the Rakhi Nala section, eastern Sulaiman Range. The studied Formation is 110-140 meters thick and consists mainly of fine to coarse-grained sandstone, with minor-siltstone, mudstone (claystone, shale), and limestone. The uppermost beds of the Moro Formation are consist of sandstone with iron types of cement. Twelve lithofacies have been identified based on a petrographic investigation related to the depositional environment of the Moro Formation ranging from deltaic to marine setting (Delta Plain-Delta front). Petrographic analysis of sandstone reveals the presence of quartz both, mono-crystalline and poly-crystalline, less feldspar; heavy minerals like hematite and magnetite, and glauconite were found in negligible amounts. Detrital mineral composition shows that in Moro Formation, the sandstone shows a litharenite. Modal composition of the sandstone from the QFL diagram was Q 66% F 0.3% L 33.7% and that of the QmFLt diagram was QM, 57% F 0.23% L 43.77%. The overall average composition is Q 61.5% F 0.27% L 38.7%. A total of 37 thin-sections are studied for provenance analysis, out of which twenty-seven samples are considered as Litharenite (this shows recycled, or craton interior origin), eight Quartz arenite categories are identified and two samples are fall in the sublitharenites category (Quarts recycled source area). پرونده مقاله -
دسترسی آزاد مقاله
2 - Facies analysis, sedimentation conditions and geochemistry of clastic deposits of Ashin formation (Late Ladinian-Early Carnian), Northeast of Nain, East of Central Iran
Payman Rezaee Mohammad Khanehbad Moasoumeh Ezatifar Seyedeh Akram Jooybari Kiamars HosseiniThe present study aims to investigate the petrographic, geochemical features, and depositional facies of the Late Triassic Ashin Formation (Nakhlak Group, central Iran). For this purpose, 100 thin sections, and 13 samples of fine-grained sedimentary rocks were analyzed چکیده کاملThe present study aims to investigate the petrographic, geochemical features, and depositional facies of the Late Triassic Ashin Formation (Nakhlak Group, central Iran). For this purpose, 100 thin sections, and 13 samples of fine-grained sedimentary rocks were analyzed for their petrographic and geochemical characteristics, taken from a 330-m thick section of this formation. The petrographic types identified in this formation include sandstone, siltstone and limestone. This study suggests limestone facies are deposited in upper parts of the distal submarine fan towards the shore, sandstone facies are deposited in the middle part of the distal submarine fan, and the shale facies are deposited in lower parts of the distal submarine fan towards the abyssal plain by turbidity currents. The plotting of petrographic data on ternary diagrams for compositional classification illustrate their composition as litharenites, sub-litharenites, and a few litharenite-feldspathic and shales. Discrete diagrams refer to a tectonic setting of a continental arc complex and the active continental margin. The results of the modal analysis and geochemical data indicate the orogenic re-cycling for these deposits. CIA and CIW indexes indicate moderate weathering of the source area under semi-arid to semi-humid climates. پرونده مقاله -
دسترسی آزاد مقاله
3 - Fluvial Facies and Provenance of the Early Permian Warchha Sandstone Salt Range, Pakistan
Shahid Ghazi Nigel P. MountneyDeposits of the Warchha Sandstone in the Salt Range, Pakistan are characterised by a range of fluvial facies and architectural elements that together preserve a record of both the proximal and distal parts of a meandering river system that drained the northern margin of چکیده کاملDeposits of the Warchha Sandstone in the Salt Range, Pakistan are characterised by a range of fluvial facies and architectural elements that together preserve a record of both the proximal and distal parts of a meandering river system that drained the northern margin of Gondwanaland. Several fining-upward cycles are recognised and completely preserved cycles can be divided in to three parts; a lower part composed of an erosive base with gravel- and coarse sand-grade trough cross-bedded facies, a middle part composed of planar cross-bedded, ripple cross-laminated and horizontally laminated sandstone facies, and an upper part composed predominantly of horizontally laminated and massive mudstone facies. Nine architectural elements are recognised within these cycles and these record the presence of channels, downstream and laterally accreting barforms, laminated sand sheets, crevasse splays, levees, over-bank floodplain units and shallow lakes. A broad range of sedimentary structures is recognised, including different forms of bedding, cross bedding, ripple marks and stratification, channels, flute casts, load casts, desiccation cracks, rain prints, conein- cone structures, a variety of concretions and bioturbation. The occurrence and abundance of these structures varies in a systematic manner throughout the vertical thickness of the succession. Cross bedding is the most prominent and consistent sedimentary structure, including various trough and planar varieties. The clasts are mainly of plutonic and low-grade metamorphic origin, with an additional minor sedimentary component. Textural properties of the sandstone are fine- to coarse-grained, poorly to moderately sorted, sub-angular to sub-rounded and with generally loose packing. Based on modal analyses, the sandstone is dominantly a sub-arkose to arkose. Detrital constituents of this formation are mainly composed of monocrystalline quartz, feldspars (more K-feldspar than plagioclase) and various types of lithic clasts. XRD and SEM studies indicate that kaolinite is the dominant clay mineral. Detailed palaeocurrent analysis reveals a broad unimodal palaeocurrent pattern within each cycle but significant changes in local migration direction between each vertically stacked cycle, supporting the notion of a high-sinuosity system with an overall dominant flow direction to the north-northwest. Petrographic analysis indicates the provenance of the Warchha Sandstone to have been the Aravalli Range to the southeast and the Malani Range to the south of the Salt Range, suggesting northward transport across a broad alluvial plain towards the margin of the Tethys Ocean in the north. پرونده مقاله -
دسترسی آزاد مقاله
4 - ژئوشیمی، پتروگرافی و خاستگاه تکتونیکی ماسهسنگهای دونین فوقانی سازند ایلانقره، شمالغرب ایران
عادل نجف زاده محمد حسین آدابی مهدی جعفرزاده خسرو خسرو تهرانینهشتههای سیلیسی- آواری سازند ایلانقره در برش ایلانلو در آذربایجان با سن دونین بالایی)فامنین( از ماسهسنگهای با رنگهای متنوع وشیلهای تیره رنگ به صورت میانلایه تشکیل شدهاند. اکثر نمونههای ماسهسنگی در برش ایلانلو از نظر مطالعات پتروگرافی از نوعکوارتز آرنایت تشخیص داده شدهان چکیده کاملنهشتههای سیلیسی- آواری سازند ایلانقره در برش ایلانلو در آذربایجان با سن دونین بالایی)فامنین( از ماسهسنگهای با رنگهای متنوع وشیلهای تیره رنگ به صورت میانلایه تشکیل شدهاند. اکثر نمونههای ماسهسنگی در برش ایلانلو از نظر مطالعات پتروگرافی از نوعکوارتز آرنایت تشخیص داده شدهاند. مطالعه ژئوشیمیایی این ماسهسنگها نیز ترکیب کوارتز آرنایتی آنها را تأیید میکند. در این مطالعه،خاستگاه، جایگاه تکتونیکی و اندیس هوازدگی این ماسهسنگها با تمرکز بر روشهای ژئوشیمیایی مورد بررسی قرار گرفته است. تفسیر نتایجحاصل از آنالیزهای ژئوشیمیایی عناصر اصلی و فرعی و استفاده از دیاگرامهای مختلف نشان میدهد که ماسهسنگهای موجود در برشایلانلو از یک منشأ کراتونی همراه با چرخه مجدد رسوبی و تحت تأثیر اقلیم گرم و مرطوب حاکم بر آن زمان، حاصل و در نهایت دریکحاشیه غیر فعال قارهای رسوبگذاری نمودهاند. با توجه به موقعیت پالئوژئوگرافی ایران در زمان دونین )شمال ابر قاره گندوانا( و قرارگیریمنطقه آذربایجان در پیشانیترین ساحل جنوبی پالئوتتیس، میتوان فرضیه ورود رسوب از سمت مناطق جنوبیتر گندوانا و نواحی خاورمیانهنظیر سپر عربستان و سپر نوبین در شرق آفریقا و رسوبگذاری نهایی در حاشیه غیر فعال قارهای اقیانوس پالئوتتیس را برای این نهشتهها درنظر گرفت پرونده مقاله -
دسترسی آزاد مقاله
5 - Provenance Based Trust Boosted Recommender System Using Boosted Vector Similarity Measure
Dhanalakshmi Teekaraman Sendhilkumar Selvaraju Mahalakshmi Guruvayur SuryanarayananAs users in an online social network are overwhelmed by the abundant amount of information, it is very hard to retrieve the preferred or required content. In this context, an online recommender system helps to filter and recommend content such as people,items or service چکیده کاملAs users in an online social network are overwhelmed by the abundant amount of information, it is very hard to retrieve the preferred or required content. In this context, an online recommender system helps to filter and recommend content such as people,items or services. But, in a real scenario, people rely more on recommendations from trusted sources than distrusting sources. Though, there are many trust based recommender systems that exist, it lag in prediction error. In order to improve the accuracy of the prediction, this paper proposes a Trust-Boosted Recommender System (TBRS). Since, the provenance derives the trust in a better way than other approaches, TBRS is built from the provenance concept. The proposed recommender system takes the provenance based fuzzy rules which were derived from the Fuzzy Decision Tree. TBRS then computes the multi-attribute vector similarity score and boosts the score with trust weight. This system is tested on the book-review dataset to recommend the top-k trustworthy reviewers.The performance of the proposed method is evaluated in terms of MAE and RMSE. The result shows that the error value of boosted similarity is lesser than without boost. The reduced error rates of the Jaccard, Dice and Cosine similarity measures are 18%, 15% and 7% respectively. Also, when the model is subjected to failure analysis, it gives better performance for unskewed data than slewed data. The models fbest, average and worst case predictions are 90%, 50% and <23% respectively. پرونده مقاله
سکوی نشر دانش
سند یا سکوی نشر دانش ،سامانه ای جهت مدیریت حوزه علمی و پژوهشی نشریات دانشگاه آزاد می باشد
پیوندهای سایت
مراکز مرتبط
پشتیبانی
صفحات رسمی
حقوق این وبسایت متعلق به سامانه مدیریت نشریات دانشگاه آزاد اسلامی است.
حق نشر © 1403-1400