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31.
Orhan Dengiz H. Huseyin Ozaytekin Gokhan Cayci Abdullah Baran 《Environmental Geology》2009,56(6):1057-1063
The objective of this research was to investigate the morphology, genesis and classification of organic soils formed on depression
and flat land around Lake Yenicaga, west-central Turkey. Formation of the area has been influenced by tectonic and karst
processes. This peatland is important in this area due to its extensive use as a horticultural plant growth medium resulting
from positive physical and chemical properties. Organic soils in the study area were formed in nutrient-rich conditions and
it is classified as typical basin peat. Four representative pedons were excavated in the study area based on extensive observations
performed with random grid method using an auger. Samples were taken from horizons in each profile for laboratory analyses.
Organic matter contents ranged from 12.5 to 91.5% across all four pedons. Fiber contents were between 4.3 and 91.5%, and N ranged from 0.56 to 2.19%. Cation exchange capacity ranged from 37 to 222 cmol kg−1, bulk density from 0.09 to 0.78 g cm−3, lime from 0.15 to 2.62%. The pH and ECe values ranged from 5.38 to 7.92 and 0.50 to 3.80 dS m−1, respectively. Sand, silt and clay contents of the organic soils ranged between 0.75–3.92, 40.70–74.77 and 24.15–57.30%,
respectively. Differences in organic soils were found to depend on the environment, botanical origins, decomposition degrees,
and groundwater composition. The organic soils of the research area were classified in the typic, hemic and hydric subgroups
of Medifibrists (Soil Taxonomy 1999). 相似文献
32.
A calcic skarn deposit occurs along the contact zone between Oligo-Miocene Çatalda? Granitoid and Mesozoic limestones in Susurluk, northwestern Turkey. The skarn zone with little or no retrograde stage is represented by fluid inclusions with high homogenization temperatures (up to >600 °C) and a wide range of salinity (12 to >70 wt.% NaCl). Pluton-derived fluids facilitated occurrence of continuous prograde reactions in the country rocks (particularly in the proximal zone) and oxygen isotopic depletion in calc-silicate and calcite minerals. δ18O of anhydrous minerals within proximal and distal zones indicate that skarn-forming fluids had a magmatic origin. The δ18O values are 5.93–9.08‰ (mean 6.8‰) for garnet, 4.08–9.94‰ (mean 6.4‰) for pyroxene, 4.89–7.92‰ (mean 6.4‰) for wollastonite and 6.65–8.28‰ (mean 7.5‰) for vesuvianite. Temperatures estimated by isotopic compositions of mineral pairs are significantly lower than those measured from the fluid inclusions, indicating that isotopic equilibrium is not preserved between the skarn minerals. δ18O and δ13C values are systematically depleted from marbles to skarn carbonates. Calc-silicate forming reactions and permeability increase triggered by volatilization and consequent strong infiltration of H2O-rich siliceous fluids into the system promoted fluid–rock interaction causing isotopic resetting and isotopic depletion of silicates (e.g. pyroxene and wollastonite) and skarn calcites. 相似文献
33.
Municipal solid waste landfill site selection using geographical information systems: a case study from Çorlu,Turkey 总被引：1，自引：0，他引：1
Orhan Arkoc 《Arabian Journal of Geosciences》2014,7(11):4975-4985
The rapid population growth due to fast urbanization in developing countries leads to environmentally sustainable and efficient management of solid waste. Insufficient solid waste landfill sites, in particular, require new areas because of rapid urbanization. This reveals the need to select appropriate landfill sites, in terms of pollution, that meet the requirements of curbing pollution. In this study, a new solid waste site selection tool was presented for the assessment and selection of areas for a municipal solid waste (MSW) landfill using a combination of point count index and constraint overlaying method with a geographical information system (GIS). For this purpose, factors affecting the site selection tool development were gathered under three groups, namely geological and natural, environmental and social–economical. For the first group, weighting for each criterion—depending upon its relative importance—was assigned, and ratings were given appropriately with their relative magnitude of impact. For the second and third groups, buffer zones were created in order to perform overlay analysis. This tool was used to perform MSW landfill selection of Çorlu District. According to the final map produced with this tool, two areas were identified within the district limits. This procedure was time saving as it was quite easy and did not require too much time and money to collect data. However, besides the usefulness of the procedure, at the final stage of decision-making, some further investigations should also be made. 相似文献
34.
35.
Orhan Ozdemir Stoyan I. Karakashev Anh V. Nguyen Jan D. Miller 《International Journal of Mineral Processing》2006
Previous research has shown that the flotation of soluble salt is determined by interfacial water structure, thermal stability, and viscosity. These salts include alkali halide and alkali oxyanion salts. Of particular interest are the carbonate salts such as those associated with the great trona deposit of the Green River basin in Wyoming. In this study, we investigated the adsorption of carbonate and bicarbonate salts at the air–brine interface and correlated the adsorption behavior with water structure. Specifically, the equilibrium and dynamic surface tensions of sodium carbonate and sodium bicarbonate salts have been measured as a function of the salt concentration up to saturation and compared with the model prediction using the Gibbs–Langmuir adsorption theory. The results show that the negative adsorption of sodium carbonate leads to a significant increase in surface tension of the brine solution. For sodium bicarbonate, both the negative adsorption and the increase in surface tension are significantly lower when compared with the sodium carbonate case. The negative adsorption is correlated with the water structure making/breaking character of carbonate and bicarbonate solutions. In particular, sodium ions are significantly more hydrated than carbonate and bicarbonate ions, and, therefore, tend to be excluded from the air–brine interface. On the other hand, carbonate and bicarbonate ions are accommodated at the air–brine interface. In any event, the balance between sodium exclusion and carbonate/bicarbonate accommodation results in an increase in the surface tension of these solutions with an increase in salt concentration. 相似文献
36.
37.
Petrogenesis of the Neogene alkaline volcanics with implications for post-collisional lithospheric thinning of the Eastern Pontides, NE Turkey 总被引：2，自引：0，他引：2
Whole-rock geochemistry, Sr–Nd–Pb isotopes and K–Ar data are reported for alkaline samples collected from the Neogene alkaline volcanics (NAVs) in the Eastern Pontides, northeastern Turkey, in order to investigate their source and petrogenesis and geodynamic evaluation of the region. The NAVs were made of three groups that comprise of basanite–tephrite (feldspar-free; Group A), tephrite–tephriphonolite (feldspar and feldspathoid-bearing; Group B) and alkaline basalt–rhyolite (feldspathoid-free; Group C) series. These rocks cover a broad compositional range from silica-undersaturated to silica-oversaturated types, almost all of which are potassic in character. They show enrichment of LREE and LILE and depletion of HFSE, without a Eu anomaly in most of the mafic samples. Textural features and calculated pressures based on the Cpx-barometer in each series indicate that the alkaline magma equilibrated at shallow crustal depths under a pressure of about 3–4.5 kbar and approximating a crystallization depth of 9–14 km. The NAVs are slightly depleted in isotopic composition, with respect to 87Sr/86Sr (ranging from 0.705018 to 0.705643) and 143Nd/144Nd (ranging from 0.512662 to 0.512714) that indicate young Nd model ages (0.51–059 Ga). This may indicate that the parent melts tapped a homogeneous and young lithospheric mantle source which was metasomatized by subduction-derived sediments during the Late Mesozoic. Pb isotopic compositions (206Pb/204Pb = 18.85–18.95; 207Pb/204Pb = 15.60–15.74; 208Pb/204Pb = 38.82–39.25) may also be consistent with a model for an enriched subcontinental lithospheric mantle source. Lithospheric thinning and resultant upwelling of asthenosphere induced by lithospheric delamination may have favoured partial melting of chemically enriched, young lithospheric mantle beneath the Eastern Pontides. Then, the melt subsequently underwent a fractional crystallization process along with or without minor amounts of crustal assimilation, generating a wide variety of rock types in a post-collision extensional regime in the Eastern Pontides during the Neogene. 相似文献
38.
Andesite exposed in different parts of Ankara has different weathering categories varying from fresh to residual soil. The geomechanical properties of the andesite are significantly affected by weathering. Buildings constructed especially in completely weathered and residual soil levels of the andesite have some geotechnical problems. In this study, the variation of the geomechanical properties of the andesite due to weathering is investigated in three selected sites of Ankara, through optical microscope, X-ray diffraction analyses, major element analyses, pressuremeter tests, physicomechanical tests, and seismic refraction method. The data gathered from the field and laboratory studies were used to assess the characteristics of the weathering zones. Based on the data obtained from this study, an idealized weathering profile is assessed. No bearing capacity and consolidation settlement problems exist in the area. However, care should be taken for immediate settlement of the buildings. Slopes with heights less than 8 m are not expected to cause any significant problems for buildings. There exists a ground amplification problem in the study area. The natural period of the building should not match that of the weathered rock. The ground response analyses reveal that the buildings with four to seven stories may be adversely affected from earthquakes due to resonance phenomenon. Therefore, this has to be taken into account when designing new buildings. 相似文献
39.
Firat Aydin Abdurrahman Saydut Beniz Gunduz Isil Aydin Candan Hamamci 《洁净——土壤、空气、水》2012,40(4):444-448
Chemical speciation of vanadium is important to understand the true nature of this element in the environment as well as its biochemical pathways. Sample pretreatment, preparation, and chemical speciation methods were applied for vanadium in coal bottom ash here. Two‐stage microwave acid digestion was used to preparation of samples. Determination of vanadium was performed using inductively coupled plasma‐optical emission spectrometry (ICP‐OES). Speciation of vanadium was carried out using a seven‐step sequential extraction procedure of the coal bottom ash each releasing species of vanadium: Water soluble, exchangeable, carbonate, reducible, oxidizable, sulfide, and residual fractions. Total vanadium concentration in the coal bottom ash is 701 mg kg?1 d.w. The most abundant form of vanadium in coal bottom ash is residual fraction of vanadium (196 mg kg?1 d.w.). Relative abundances of the remaining vanadium fractions in coal bottom ash are as follows: Reducible (176 mg kg?1 d.w.) > sulfide (176 mg kg?1 d.w.) > carbonate (85 mg kg?1 d.w.) > oxidizable (50 mg kg?1 d.w.) > water soluble (10.6 mg kg?1 d.w.) > exchangeable (9.0 mg kg?1 d.w.). 相似文献
40.
An Assessment of the Seismicity of the Bursa Region from a Temporary Seismic Network 总被引：2，自引：0，他引：2
A temporary earthquake station network of 11 seismological recorders was operated in the Bursa region, south of the Marmara
Sea in the northwest of Turkey, which is located at the southern strand of the North Anatolian Fault Zone (NAFZ). We located
384 earthquakes out of a total of 582 recorded events that span the study area between 28.50–30.00°E longitudes and 39.75–40.75°N
latitudes. The depth of most events was found to be less than 29 km, and the magnitude interval ranges were between 0.3 ≤ ML ≤ 5.4, with RMS less than or equal to 0.2. Seismic activities were concentrated southeast of Uludag Mountain (UM), in the
Kestel-Igdir area and along the Gemlik Fault (GF). In the study, we computed 10 focal mechanisms from temporary and permanents
networks. The predominant feature of the computed focal mechanisms is the relatively widespread near horizontal northwest-southeast
(NW–SE) T-axis orientation. These fault planes have been used to obtain the orientation and shape factor (R, magnitude stress ratio)
of the principal stress tensors (σ1, σ2, σ3). The resulting stress tensors reveal σ1 closer to the vertical (oriented NE–SW) and σ2, σ3 horizontal with R = 0.5. These results confirm that Bursa and its vicinity could be defined by an extensional regime showing a primarily normal
to oblique-slip motion character. It differs from what might be expected from the stress tensor inversion for the NAFZ. Different
fault patterns related to structural heterogeneity from the north to the south in the study area caused a change in the stress
regime from strike-slip to normal faulting. 相似文献