Hydrogeochemical evaluation of Umut geothermal field (SW Turkey)     

Özgür Avşar  Göktuğ Altuntaş 《Environmental Earth Sciences》2017,76(16):582

Tekkehamam geothermal field is located in the South of Menderes Graben (Aegean region) and is one of the most important geothermal sites of Western Anatolia. Umut geothermal field is a part of the Tekkehamam field. This study was conducted in order to determine the origin and hydrogeochemical properties of the geothermal waters. For this purpose, sampling was done in order to check the chemistry of the water, and ¹⁸O, ²H isotope analyses done at four wells, nine natural springs and three cold water sources. According to the results of the chemical analysis, the geothermal waters were determined to be of Na + K-SO₄ type. Additionally, ¹⁴C and ³H analyses were done in selected well and spring waters for the purpose of age determination of groundwater; most of the waters were determined to be submodern. Geothermometer calculations show that the reservoir temperature for the Umut geothermal field ranges between 148 and 180 °C. Stable isotope results indicate that Umut geothermal waters are meteoric in origin. Mixing between shallow and deep waters is the dominant subsurface process that determines the physical and chemical character of the waters.  相似文献   

Investigation of the Kumdanlı and surrounding faults on the Eğirdir Lake by conducting ground penetrating radar (GPR) profiles     

Hasan Hüseyin Aksu  Mehmet Zakir Kanbur  Muhittin Görmüş 《Arabian Journal of Geosciences》2017,10(17):387

A ground penetrating radar (GPR) survey was performed on the E?irdir Lake to obtain the structural properties of Kumdanl? and surrounding faults. GPR data was collected along ten profiles in various directions by using 100–200-MHz GPR antennas. The radar sections showed that the Kumdanl? Fault, SW-NE in direction, and also some other neighboring NW-SE normal faults have played an active role in forming the E?irdir-Hoyran Lakes. The deformation and the geometry obtained from the results show that the Kumdanl? Fault is a sinistral strike-slip fault including oblique and segmented displacements. The other faults (Kemerdam? and Akkeçili) have mainly normal fault systems. Their trends are generally NW-SE in direction. It is also observed that they are younger than the Kumdanl? Fault system. These fault properties demonstrate the E?irdir Lake side has an extensional structure trending SW-NE.  相似文献   

Displacement amplification factors for steel eccentrically braced frames          下载免费PDF全文

Ahmet Kuşy𝚤lmaz  Cem Topkaya 《地震工程与结构动力学》2015,44(2):167-184

Inelastic deformation capacity of links is a factor that significantly influences design of steel eccentrically braced frames (EBFs). The link rotation angle is used to describe inelastic link deformation. The link rotation angle is generally calculated by making use of design story drifts that in turn are calculated by modifying the elastic displacements by a displacement amplification factor. This paper presents a numerical study undertaken to evaluate the displacement amplification factor given in ASCE7‐10 for EBFs and the rigid‐plastic mechanism used for calculating link rotation angles. A total of 72 EBFs were designed by considering the number of stories, the bay width, the link length to bay width ratio, and the seismic hazard level as the prime variables. All structures were analyzed using elastic and inelastic time history analyses. The results indicated that the displacement amplification factor given in ASCE7‐10 provides unconservative estimates of the story drifts. On the other hand, the rigid‐plastic mechanism provides conservative estimates of link rotations. Based on the results of the numerical study, a new set of displacement amplification factors that vary along the height of the structure and modifications to the rigid‐plastic mechanism were developed. In light of the proposed modifications, the EBFs were redesigned and analyzed using inelastic time history analysis. The results indicated that the proposed modifications provide improvements for the displacement amplification factor and link rotation angle calculation procedures. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Joint parameter estimation from magnetic resonance and vertical electric soundings using a multi‐objective genetic algorithm     

İrfan Akca  Thomas Günther  Mike Müller‐Petke  Ahmet T. Başokur  Ugur Yaramanci 《Geophysical Prospecting》2014,62(2):364-376

Magnetic resonance sounding (MRS) has increasingly become an important method in hydrogeophysics because it allows for estimations of essential hydraulic properties such as porosity and hydraulic conductivity. A resistivity model is required for magnetic resonance sounding modelling and inversion. Therefore, joint interpretation or inversion is favourable to reduce the ambiguities that arise in separate magnetic resonance sounding and vertical electrical sounding (VES) inversions. A new method is suggested for the joint inversion of magnetic resonance sounding and vertical electrical sounding data. A one‐dimensional blocky model with varying layer thicknesses is used for the subsurface discretization. Instead of conventional derivative‐based inversion schemes that are strongly dependent on initial models, a global multi‐objective optimization scheme (a genetic algorithm [GA] in this case) is preferred to examine a set of possible solutions in a predefined search space. Multi‐objective joint optimization avoids the domination of one objective over the other without applying a weighting scheme. The outcome is a group of non‐dominated optimal solutions referred to as the Pareto‐optimal set. Tests conducted using synthetic data show that the multi‐objective joint optimization approximates the joint model parameters within the experimental error level and illustrates the range of trade‐off solutions, which is useful for understanding the consistency and conflicts between two models and objectives. Overall, the Levenberg‐Marquardt inversion of field data measured during a survey on a North Sea island presents similar solutions. However, the multi‐objective genetic algorithm method presents an efficient method for exploring the search space by producing a set of non‐dominated solutions. Borehole data were used to provide a verification of the inversion outcomes and indicate that the suggested genetic algorithm method is complementary for derivative‐based inversions.  相似文献   

Gas/Substrate Fluxes and Microbial Community in Phenol Biodegradation Using an O2‐Based Membrane Biofilm Reactor          下载免费PDF全文

Özge Hanay  Ergin Taşkan  Burçin Yıldız  Halil Hasar  Eoin Casey 《洁净——土壤、空气、水》2014,42(1):36-42

  相似文献   

山东栖霞桃村地区中酸性火山-侵入杂岩岩石地球化学及其成因研究     

韩宗珠  张贺  丁蒙蒙  塔金璐  徐翠玲  刘明 《中国海洋大学学报(自然科学版)》2013,(1):68-76

山东栖霞桃村地区出露中生代中酸性火山-侵入杂岩,对采自桃村地区青山组下段的中酸性火山-侵入岩以进行了岩石学和地球化学研究。桃村地区的中酸性火成岩的地球化学特征为:高钾低钠,高铝低镁;Cr,Co,Ni含量较低,Sr/Y及(La/Yb)N比值很高;微量元素蛛网图显示富集不相容元素K,Rb,Ba和Th,以及不相容元素Ce,Hf和Ti,亏损高场强元素Ta,Nb以及P;轻重稀土元素分馏程度高,具有类似埃达克岩的性质。综合分析其地球化学特征显示,青山组下段中酸性杂岩为增厚的下地壳熔融,这种地壳的增厚作用可能由古太平洋板块俯冲作用引起,而在俯冲作用过程中青山组中酸性杂岩的源岩被俯冲沉积物混染。  相似文献   

The contribution of aeolian processes to fluvial sediment yield from a desert watershed in the Ordos Plateau,China   总被引：2，自引：0，他引：2       下载免费PDF全文

Wanquan Ta  Haibin Wang  Xiaopeng Jia 《水文研究》2015,29(1):80-89

In arid zones, many active aeolian dunes terminate at ephemeral and perennial desert rivers. The desert rivers show very high rates of sediment transport that cause deleterious downstream effects on the river system and ecology. High sediment loading has been attributed to severe water erosion of sparsely covered watersheds during infrequent but heavy rainfall. Although aeolian erosion is known to lead to high rates of wind‐blown sand transport, direct confirmation of whether the aeolian processes accelerate or inhibit fluvial sediment loss is lacking. Here, we show that an aeolian‐fluvial cycling process is responsible for the high rate of suspended sediment transport in a Sudalaer ephemeral desert channel in the Ordos Plateau of China. Frequent aeolian processes, but low frequency (once every 3 years on average) flooding, occur in this region. Wind‐blown saltating grains appeared to be unable to cross the desert channel because of interruption of channel‐induced recirculating air flow, and therefore tended to settle in the channel during the windy seasons, leading to channel narrowing. During flooding, this narrowed channel was found to yield a threefold increase in suspended sediment loading and a 3.4‐fold increase in the weight percentage of the 0.08–0.2 mm sediment fraction on 18 July 2012. Loss of stored aeolian sand due to channel erosion accounted for about half of the total sediment yield in this watershed. These findings show that aeolian processes play an essential role in accelerating the sediment yield from a watershed characterized by aeolian‐fluvial interplay and also suggest that the drier the region and the greater the aeolian process, the more the aeolian process contributes to fluvial sediment yield. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Flow dynamics at the origin of thin clayey sand lacustrine turbidites: Examples from Lake Hazar,Turkey          下载免费PDF全文

Sophie Hage  Aurélia Hubert‐Ferrari  Laura Lamair  Ulaş Avşar  Meriam El Ouahabi  Maarten Van Daele  Frédéric Boulvain  Mohamed Ali Bahri  Alain Seret  Alain Plenevaux 《Sedimentology》2017,64(7):1929-1956

Turbidity currents and their deposits can be investigated using several methods, i.e. direct monitoring, physical and numerical modelling, sediment cores and outcrops. The present study focused on thin clayey sand turbidites found in Lake Hazar (Turkey) occurring in eleven clusters of closely spaced thin beds. Depositional processes and sources for three of those eleven clusters are studied at three coring sites. Bathymetrical data and seismic reflection profiles are used to understand the specific geomorphology of each site. X‐ray, thin sections and CT scan imagery combined with grain‐size, geochemical and mineralogical measurements on the cores allow characterization of the turbidites. Turbidites included in each cluster were produced by remobilization of surficial slope sediment, a process identified in very few studies worldwide. Three types of turbidites are distinguished and compared with deposits obtained in flume studies published in the literature. Type 1 is made of an ungraded clayey silt layer issued from a cohesive flow. Type 2 is composed of a partially graded clayey sand layer overlain by a mud cap, attributed to a transitional flow. Type 3 corresponds to a graded clayey sand layer overlain by a mud cap issued from a turbulence‐dominated flow. While the published experimental studies show that turbulence is damped by cohesion for low clay content, type 3 deposits of this study show evidence for a turbulence‐dominated mechanism despite their high clay content. This divergence may in part relate to input variables, such as water chemistry and clay mineralogy, that are not routinely considered in experimental studies. Furthermore, the large sedimentological variety observed in the turbidites from one coring site to another is related to the evolution of a sediment flow within a field‐scale basin made of a complex physiography that cannot be tackled by flume experiments.  相似文献   

Key pluvial parameters in assessing rainfall erosivity in the south-west development region,Romania     

Monica Dumitraşcu  Carmen-Sofia Dragotă  Ines Grigorescu  Costin Dumitraşcu  Alina Vlăduţ 《Journal of Earth System Science》2017,126(4):60

Located in the south-western part of Romania, the south-west development region overlaps the main relief forms: the Carpathians mountains, the Getic Subcarpathians, the Getic piedmont, the Romanian plain and the Danube valley. The study aims at providing an overview on the main pluvial parameters and their role in assessing rainfall erosivity in the study area. The authors assessed the occurrence, frequency and magnitude of some of the most significant pluvial parameters and their impact on the climatic aggressiveness in the study area. Thus, the monthly and annual mean and extreme climatic values for different rainfall related parameters (e.g., maximum amounts of precipitation/24 hr, heavy rainfall), as well as relevant indices and indicators for pluvial aggressiveness (Fournier, Fournier Modified, Angot) were calculated. The rainfall erosivity was assessed in order to provide both the spatial distribution of the triggering extreme weather phenomena and the resulted intensity classes for the analysed indices and indicators. The authors used long-term precipitation records (1961–2010) for the selected relevant meteorological stations distributed throughout all analysed relief units.  相似文献   

Batch and Column Experiments to Support Heavy Metals (Cu,Zn, and Mn) Transport Modeling in Alluvial Sediments Between the Mogan Lake and the Eymir Lake,Gölbaşı, Ankara     

E. Dişli 《Ground Water Monitoring & Remediation》2010,30(3):125-139

This article describes laboratory batch sorption and column transport experiments that were conducted using heterogeneous alluvial sediments with a wide physical characteristic from wells, located between Lake Mogan and Lake Eymir, Gölbaşı, Ankara. The batch sorption experiment was conducted in two separate systems, that is, single and multicomponents. Single batch experiment was performed to determine equilibrium condition between the heavy metal ions and the soil adsorption sites. The sorption isotherms data from multibatch experiments were used to calculate the sorption parameters. Single batch experiment indicated that equilibrium was attained within 9 days from the start of the sorption test. As a result of multicomponents batch experiments, for Zn and Mn, the sorption process was well described by the Freundlich or Langmuir isotherm model, whereas sorption of Cu was better described by the linear isotherm model. The K_d of Cu were found to be highest in soil 1 (32550.350 L kg⁻¹) and lowest in soil 5 (18170.76 L kg⁻¹). The maximum and minimum sorption capacity values for Zn were found to be in soil 1 (10985.148 mg kg⁻¹) and in soil 2 (8597.14 mg kg⁻¹) units, respectively. [Correction added after online publication 15 July, 2010: In the preceding sentence, the words “minimum” and “maximum” were initially switched.] Similarly, soil 1 (7587.391 mg kg⁻¹) and soil 5 (4908.695 mg kg⁻¹) units provided the maximum and minimum values for Mn. In the column experiments, flow and tracer transport was studied under saturated conditions using conservative tracer to determine the transport parameters. Transport parameter values were obtained by curve-fitting using the nonlinear least-squares optimization code CXTFIT. Results of the column experiments indicated that the dispersivity values obtained for soil samples were in the range of 0.024 to 1.13 cm.  相似文献