Sedimentology
Hoda Bavi; Reza Moussavi-Haramia; Mohamad Hosein Mahmudy-Gharaie; Hamed Zand-Moghadam; Asadollah Mahboubi; Mohammad Reza Tohidi
Abstract
The geochemical separation pattern and environmental behavior of rare earth elements (ΣREE) have been investigated in 5 different sedimentary systems related to the Dar-e-Allo copper mine. For this purpose, the total concentration and sequential patterns of ΣREE elements were determined using ...
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The geochemical separation pattern and environmental behavior of rare earth elements (ΣREE) have been investigated in 5 different sedimentary systems related to the Dar-e-Allo copper mine. For this purpose, the total concentration and sequential patterns of ΣREE elements were determined using multi-acid digestion and mBCR (Modified Community Bureau of Reference, European Commission) selective extraction method. The normalization patterns of the total concentration of ΣREE are drawn based on the average North American Shale Composition (NASC) and Upper Continental Crust (UCC). General trends of concentration changes in the five sedimentary systems are very similar to each other, and the concentration of LREEs is higher than that HREEs, just a sample taken from under the rock dump that contains sulfide-leached elements shows a pattern different from other samples and standard patterns. Opposite of the changes in the concentration of ΣREEs, more enrichment is seen in HREEs compared to LREEs. This pattern of enrichment changes is consistent with the higher tendency of HREEs than LREEs for mobility during weathering and oxidation. The geochemical separation patterns of ΣREEs in natural sediment and samples containing iron and manganese oxides are mainly dominated by the residual fraction. Surprisingly, considering the different conditions of formation and stability in the samples taken from the waterways leading to the mine, evaporite deposits and sediments washed from the rock dump, the separation pattern of ΣREEs is controlled mainly with two parts soluble in Acid and reducible fraction. According to the enrichment trends, the trend of mobility and bioavailability from LREEs to HREEs increases with an upward slope. These results show that speciation, geochemical separation pattern and environmental behavior for ΣREEs without considering key environmental factors lead to a lack of understanding or even misinterpretation. The results of this study can be used as a reference in organizing the mine development and environmental planning of the Dar-e-Allo copper mine.
Sedimentology
Sara Ebrahimi Meymand; Hamed Zand-Moghadam; Mohammad Khanehbad; Asadollah Mahboubi Mahboubi; Gholamreza Hosseinyar
Abstract
Nebkhas are one of the aeolian dunes that play an important role in wind erosion by stabilizing sediments around plants. Due to the depression of northern Shahdad plain (eastern Kerman), the sever wind impact, high rate of sediment supply and the presence of desert plants, nebkhas have expanded. In this ...
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Nebkhas are one of the aeolian dunes that play an important role in wind erosion by stabilizing sediments around plants. Due to the depression of northern Shahdad plain (eastern Kerman), the sever wind impact, high rate of sediment supply and the presence of desert plants, nebkhas have expanded. In this study in order to achieve the formation of nebkha in the Shahdad plain, sedimentological parameters and the effect of vegetation on nebkha geomorphology have been investigated. Due to the expansion of the study area and the different geomorphology of the nebkha, 30 nebkha were sampled along with sediments between them. the analysis of these sediments shows that nebkha sediments are often fine sand sizes that are well-sorted and rounded. However, sediments between nebkha often have a range between gravel (pebble) and fine silt which are subdivided into either surface and sub-surface sediments (depth greater than 2 centimeters). Surface sediments are often coarse grains (granule to coarse sand) and have relatively well roundness and sorting. Field investigations and analyses have shown that genus and plant species are important in the geomorphology of nebkhas in the Shahdad plain but the effect of vegetation on the sedimentary parameters is insignificant. This is due to the fact that the three types of vegetation identified (Tamarix stricta, Seditzia rosmarinus, Prosopis farcta), the highest levels of nebkha is for Tamarix stricta but the sedimentary parameters with different vegetation are not significantly different.
Sedimentology
Hamed Zand-Moghadam
Abstract
The Badamu Formation with Middle-Upper Jurassic (late Toarcian-Early Bajocian) age introduced as third formation of Shemshak Group in the Central Iran that for facies studies and depositional environment, the Bolbolueih section in SE Kerman with thickness 144m were selected and sampled. Facies analyses ...
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The Badamu Formation with Middle-Upper Jurassic (late Toarcian-Early Bajocian) age introduced as third formation of Shemshak Group in the Central Iran that for facies studies and depositional environment, the Bolbolueih section in SE Kerman with thickness 144m were selected and sampled. Facies analyses of Badamu Formation led to identification of 16 lithofacies that classified into four facies associations including carbonate, siliciclastic, hetrolitic carbonate-siliciclastic and oolithic ironstone. The important facies of the Badamu Formation in studied section is oolitic calcarenaite facies (La) that according to textural and structural features classified into six lithofacies (Lah, Lal, Lap, Lam, Lar and Lat). The sorted ooides in grainstone microfacies accompanied by structural evidences such as cross-bedding with bimodal to bipolar palaeocurents, hummocky and herringbone cross-beds, reactivation surfaces, wavy ripple marks and rain drop imprints reveal that this facies were deposited in shallow beach environment. Textural and structural characterizes in the associated facies (sandstone and hetrolitic fasies) such as high textural and compositional maturity and flaser bedding is consistent with this interpretation. Vertical and lateral accretions of the recognized facies show that the Badamu Formation successions have been deposited in shoreface subenvironment in the beach and beach ridges model framework.
