The Maastrichtian-Danian in the SW Zagros Fold-Thrust Belt (S. Iran): An Integration of Planktonic Foraminiferal Biostratigraphy and Gamma-Ray Spectrometry

In this study, the Maastrichtian-Danian boundary was measured and sampled in two stratigraphic sections, the north and south flanks of the Dehnow anticline in Coastal Fars, Southern Iran. This boundary was also investigated in the drilled exploratory well-1 in the same region. The lithology of the Maastrichtian-Danian deposits consists of glauconitic, phosphatic argillaceous limestones and marlstones. 30 genera and 77 species of planktonic foraminifera have been determined. The recognized biozon...     

Biostratigraphy,Microfacies, Sedimentary Environments and Sequence Stratigraphy of the Late Devonian–Carboniferous Deposits at the Anarak Section,Central Iran

The Late Devonian–early Carboniferous deposits of the Anarak section in northeastern Isfahan, Central Iran, evaluated based on conodont biostratigraphy, sedimentary environment and sequence stratigraphy. According to the field observations, five lithological units were identified. Investigating the conodont fauna of the Late Devonian–Carboniferous(Mississippian–Pennsylvanian) deposits of Bahram, Shishtu, and Qaleh(Sardar 1) formations in Anarak section led to the identification of 67 species of ...     

Nematode community structure in relation to metals in the southern of Caspian Sea

Spatial distribution and structure of nematode assemblages in coastal sediments of the southern part of the Caspian Sea were studied in relation to environmental factors. By considering metals, organic matter, Shannon diversity index(H), maturity index(MI) and trophic diversity(ITD), ecological quality status of sediment was also determined. Fifteen nematode species belonging to eleven genera were identified at the sampling sites. Average density of nematode inhabiting in sediment of the studied area was 139.78±98.91(ind. per 15.20 cm~2). According to redundancy analysis(RDA), there was high correlation between metals and some species. Based on biological indicators, the studied area had different environmental quality. Generally, chemical and biological indices showed different results while biological indices displayed similar results in more sites.     

Reduction of local scour around bridge pier groups using collars

In this paper reduction of scour around group of two and three piers using circular collar has been carried out for the case of clear-water flow over uniform sediment. The efficiency of collars, with different sizes and spaces between piers is studied through experiments in group of two and three piers. The result reveals that collar has more influence in reduction of scour depth in rear piers than the first pier. Also, when the spacing between the piers increases the area without protection between the piers is washed away resulting deeper scour holes at the rear piers.     

Applicability of generalized additive model in groundwater potential modelling and comparison its performance by bivariate statistical methods

Groundwater is the most valuable natural resource in arid areas. Therefore, any attempt to investigate potential zones of groundwater for further management of water supply is necessary. Hence, many researchers have worked on this subject all around the world. On the other hand, the Generalized Additive Model (GAM) has been applied to environmental and ecological modelling, but its applicability to other kinds of predictive modelling such as groundwater potential mapping has not yet been investigated. Therefore, the main purpose of this study is to evaluate the performance of GAM model and then its comparison with three popular GIS-based bivariate statistical methods, namely Frequency Ratio (FR), Statistical Index (SI) and Weight-of-Evidence (WOE) for producing groundwater spring potential map (GSPM) in Lorestan Province Iran. To achieve this, out of 6439 existed springs, 4291 spring locations were selected for training phase and the remaining 2147 springs for model evaluation. Next, the thematic layers of 12 effective spring parameters including altitude, plan curvature, slope angle, slope aspect, drainage density, distance from rivers, topographic wetness index, fault density, distance from fault, lithology, soil and land use/land cover were mapped and integrated using the ArcGIS 10.2 software to generate a groundwater prospect map using mentioned approaches. The produced GSPMs were then classified into four distinct groundwater potential zones, namely low, moderate, high and very high classes. The results of the analysis were finally validated using the receiver operating characteristic (ROC) curve technique. The results indicated that out of four models, SI is superior (prediction accuracy of 85.4%) following by FR, GAM and WOE, respectively (prediction accuracy of 83.7, 77 and 76.3%). The result of groundwater spring potential map is helpful as a guide for engineers in water resources management and land use planning in order to select suitable areas to implement development schemes and also government entities.     

Classification of Satellite Images in Assessing Urban Land Use Change Using Scale Optimization in Object-Oriented Processes (A Case Study: Ardabil City,Iran)

By using satellite imagery, the recognition and evaluation of various phenomena and extraction of information necessary for the planning of land resources or other purposes are easily accomplished. The purpose of this study is to compare the efficiency of seven commonly used methods of monitored classification of satellite data to evaluate land use changes using TM and OLI Landsat, IRS, Spot5 and Quick Bird bands as well as different color combinations of these images to detect agricultural land, residential areas and aquatic areas using object-oriented processing. Digital processing of satellite images was carried out in 1998 and 2016 using advanced methods. Training samples were extracted in five user classes by eCognition software using segmentation scale optimization, different color combinations and coefficients of shape and compression. The appropriate segmentation scale for arable land, human complications and the blue areas were, respectively, 50, 8 and 10. Then each image was classified separately using seven methods and extracted samples, and efficiency of each classification method was obtained by calculating two general health and Kappa coefficients. The results show that the accuracy of each classification method and the neural network with a total accuracy of 94.475 and Kappa coefficient of 92.095 were selected as the most accurate classification method. These results show that the sampling of educational samples with proper precision of the classes in the images and dependency probability of each satellite images pixel can be useful in classifying group available in helpful area.     

Early Mesozoic sedimentary‒tectonic evolution of the Central-East Iranian Microcontinent: Evidence from a provenance study of the Nakhlak Group

In Central Iran, the mixed siliciclastic?carbonate Nakhlak Group of Triassic age is commonly seen to have a Cimmerian affinity, although it shows considerable resemblances with the Triassic Aghdarband Group in far northeastern Iran, east of Kopeh-Dagh area, with Eurasian affinity. The Nakhlak Group is composed of the Alam (Late Olenekian?Anisian), Baqoroq (Late Anisian??Early Ladinian), and Ashin (Ladinian??Early Carnian) formations consisting mainly of volcanoclastic sandstone and shale and fossiliferous limestone. The Baqoroq Formation contains also metamorphic detritus. Sandstone petrofacies reflect the detrital evolution from active volcanism to growing orogen and again active volcanism. Textural and modal analyses of volcanic lithic fragments from the Alam Formation reflect the eruption style and magma composition of a felsic to intermediate syn-sedimentary arc activity. The detrital modes of the Baqoroq Formation sediments suggest a recycled orogenic source followed by arc activity in a remnant fore-arc basin. The sandstone samples from the Ashin Formation demonstrate a continuity of felsic to intermediate arc activity. Major and trace element concentrations of the Nakhlak Group clastic samples support sediment supply from first-cycle material and felsic magmatic arc input. The enrichment in LREE, the negative Eu anomalies, and the flat HREE patterns indicate origination from the old upper continental crust and young arc material. The chemical index of alteration (CIA ～51–70 for sandstone and 64–76 for shale samples) indicates medium degrees of chemical weathering at the source. Petrographical and geochemical evidence together with facies analysis constructed the following depositional conditions for the Nakhlak Group sediments: In the Olenekian, a fore-arc shallow to deep marine depositional basin developed that later was filled by recycled and arc-related detritus and changed into a continental basin in the Anisian. Ladinian extension let to a deepening of the basin. With respect to the similarities between the Nakhlak and Aghdarband (NE Iran) groups and unusual present-day position of the Nakhlak Group with no stratigraphic connection to the surrounding area, the development of first a fore-arc basin and later change into a back-arc depositional basin in close relation with the Aghdarband basin at the southern Eurasian active margin in the Triassic are here proposed. Understanding the basin development recorded in the Nakhlak Group provides constraints on the closure history of Palaeotethys and of the tectonic evolution of early Mesozoic basins at the southern Eurasian margin before the Cimmerian Orogeny.     

Effect of dry density,soil texture and time-spatial variable water content on the soil thermal conductivity

Study of the heat transfer process in saturated and unsaturated soils requires, basically, a relationship between thermal conductivity and the characteristics of the soil, such as water content, dry density and texture of the soil. This study intends to produce a generic model that can predict soil thermal conductivity with the help of easily measurable parameters. The proposed model is first calibrated using measured thermal conductivities from literature data. In order to validate the proposed model the predicted thermal conductivity of this proposed model as well as existing ones are compared with the measured thermal conductivity in literature for different soils. Validation of the proposed model was also performed on our experimental results obtained for a compacted Misillac sand and in-situ clay loam soils. The results show an average of 15% improvement in prediction accuracy for the proposed model compared to the existing models, considering all soil textures. Moreover, we perform a model to estimate thermal conductivity over time throughout the profile of soil in the context of seasonal variation of temperature. The proposed model shows an important effect of heterogeneity on the thermal conductivity variations of a double layered soil.