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101.
102.
Forty-four boulders from moraines in two glacial valleys of Mount Erciyes (38.53°N, 35.45°E, 3917 m), central Turkey, dated with cosmogenic chlorine-36 (36Cl), indicate four periods of glacial activity in the past 22 ka (1 ka = 1000 calendar years). Last Glacial Maximum (LGM) glaciers were the most extensive, reaching 6 km in length and descending to an altitude of 2150 m above sea level. These glaciers started retreating 21.3 ± 0.9 ka (1σ) ago. They readvanced and retreated by 14.6 ± 1.2 ka ago (Lateglacial), and again by 9.3 ± 0.5 ka ago (Early Holocene). The latest advance took place 3.8 ± 0.4 ka ago (Late Holocene). Using glacier modeling together with paleoclimate proxy data from the region, we reconstructed the paleoclimate at these four discrete times. The results show that LGM climate was 8–11 °C colder than today and moisture levels were somewhat similar to modern values, with a range between 20% more and 25% less than today. The analysis of Lateglacial advance suggests that the climate was colder by 4.5–6.4 °C based on up to 1.5 times wetter conditions. The Early Holocene was 2.1–4.9 °C colder and up to twice as wet as today, while the Late Holocene was 2.4–3 °C colder and its precipitation amounts approached to similar conditions as today. Our paleoclimate reconstructions show a general trend of warming for the last 22 ka, and an increase of moisture until Early Holocene, and a decrease after that time. The recent glacier terminates at 3450 m on the northwest side of the mountain. It is a remnant from the last advance (possibly during the Little Ice Age). Repeated measurements of glacier length between 1902 and 2008 reveal a retreat rate of 4.2 m per year, which corresponds to a warming rate of 0.9–1.2 °C per century. 相似文献
103.
Cem Tokatli Arzu Çiçek Özgür Emiroğlu Naime Arslan Esengül Köse Hayri Dayioğlu 《Environmental Earth Sciences》2014,71(5):2185-2197
Emet Stream is one of the most important branches of Uluabat Lake (Ramsar area) and also one of Turkey’s most important river systems. In addition to the geologic structure of the basin, Harmancik Chromium Mines are one of the most important inorganic pollution sources for the basin and also for Uluabat Lake. In the present study, water, sediment and fish (Squalius cii, Capoeta tinca and Barbus oligolepis) samples were collected seasonally from eight stations (one of them was on the Kinik Stream where the Harmancik Chromium Mines is located on and one of them was on the Dursunbey Stream) on the Emet Stream Basin. Some limnological parameters (pH, conductivity and total hardness) in water and Cr, Ca, Mg, Ni and Mn levels in biotic (muscle, gill, liver and kidney tissues of fishes) and abiotic (water and sediment) components of basin were determined to evaluate the effects of Harmancik Chromium Mines on the system. Cluster Analysis, Factor Analysis, Pearson Correlation Index, One Way Anova Tests, Scatter dot Comparing and Matrix plot Distribution Diagrams were applied to the results in order to estimate the data properly. Water samples were evaluated according to the water quality criteria for Turkey and sediment samples were evaluated according to the sediment quality criteria. According to data obtained, statistically significance differences were identified between Kinik and Emet Streams according to Cr and Ni accumulations in water and sediment. Chromium levels of Kinik Stream were extremely higher an average of 153 times for water and 10 times for sediment than uncontaminated stations. Water and sediment quality of Emet Stream were decreasing after falling the Kinik Stream and increasing after falling the Dursunbey Stream. It was also determined that, the amount of chromium in muscle tissues of three fish species were much higher than the limit value of 0.15 mg kg?1 that FAO identified. 相似文献
104.
Hydrogeochemical and isotopic characteristics of the Ilica geothermal system (Erzurum,Turkey) 总被引:1,自引:0,他引:1
In this paper, the hydrochemical isotopic characteristics of samples collected from geothermal springs in the Ilica geothermal field, Eastern Anatolia of Turkey, are examined and described. Low-temperature geothermal system of Ilica (Erzurum, Turkey) located along the Eastern Anatolian fault zone was investigated for hydrogeochemical and isotopic characteristics. The study of ionic and isotopic contents shows that the thermal water of Ilica is mainly, locally fed by groundwater, which changes chemically and isotopically during its circulation within the major fault zone reaching depths. The thermal spring has a temperature of 29–39 °C, with electrical conductivity ranging from 4,000 to 7,510 µS/cm and the thermal water is of Na–HCO3–Cl water type. The chemical geothermometers applied in the Ilica geothermal waters yielded a maximum reservoir temperature of 142 °C according to the silica geothermometers. The thermal waters are undersaturated with respect to gypsum, anhydrite and halite, and oversaturated with respect to dolomite. The dolomite mineral possibly caused scaling when obtaining the thermal waters in the study area. According to the enthalpy chloride-mixing model, cold water to the thermal water-mixing ratio is changing between 69.8 and 75 %. The δ18O–δ2H compositions obviously indicate meteoric origin of the waters. Thermal water springs derived from continental precipitation falling on to higher elevations in the study area. The δ13C ratio for dissolved inorganic carbonate in the waters lies between 4.63 and 6.48 ‰. In low-temperature waters carbon is considered as originating from volcanic (mantle) CO2. 相似文献
105.
The distribution and sources of heavy metals in Izmit Bay surface sediments affected by a polluted stream 总被引:20,自引:0,他引:20
Pekey H 《Marine pollution bulletin》2006,52(10):1197-1208
Dil Deresi stream is a highly contaminated stream passing through the most heavily industrialized area of Izmit Bay. In this research, surface sediments in the <63-microm fraction collected from 34 sites at western part of Izmit Bay, Northeastern Marmara Sea, Turkey were analyzed by ICP-AES for Al, As, Cd, Co, Cr, Cu, Fe, Mg, Mn, Ni, Pb, Sn and Zn. Metal concentrations were compared with the marine sediment quality standards (SQS) and literature data to assess the pollution status of the sediments. Enrichment factors (EFs) were calculated to assess whether the concentrations observed represent background or contaminated levels. The analysis revealed three groups of elements: (1) Sn is the most enriched element; (2) As, Cd, Pb and Zn are minor enriched elements; and (3) Co, Cr, Cu, Fe, Mg, Mn and Ni are at background concentrations. The distribution maps of the concentrations and enrichment factors for all heavy metals were also produced as a contour plot based on Geographic Information System (GIS) technology. 相似文献
106.
Çetin Koca 《International journal of geographical information science》2014,28(9):1821-1847
Terrain rendering is a crucial part of many real-time applications. The easiest way to process and visualize terrain data in real time is to constrain the terrain model in several ways. This decreases the amount of data to be processed and the amount of processing power needed, but at the cost of expressivity and the ability to create complex terrains. The most popular terrain representation is a regular 2D grid, where the vertices are displaced in a third dimension by a displacement map, called a heightmap. This is the simplest way to represent terrain, and although it allows fast processing, it cannot model terrains with volumetric features. Volumetric approaches sample the 3D space by subdividing it into a 3D grid and represent the terrain as occupied voxels. They can represent volumetric features but they require computationally intensive algorithms for rendering, and their memory requirements are high. We propose a novel representation that combines the voxel and heightmap approaches, and is expressive enough to allow creating terrains with caves, overhangs, cliffs, and arches, and efficient enough to allow terrain editing, deformations, and rendering in real time. 相似文献
107.
Hakan Yavaolu Ergin Tar Okan Tüysüz Ziyadin akr Semih Ergintav 《Journal of Geodynamics》2011,51(5):339-343
The North Anatolian Fault (NAF), which extends from Karl?ova in Eastern Turkey to the Gulf of Saros in the Northern Aegean Sea, is one of the longest active strike-slip faults in the world with a length of about 1500 km. Within the North Anatolian Shear Zone (NASZ) there are long splays off the main trunk of the NAF veering towards the interior parts of Anatolia. Although the whole shear zone is still seismically active, the major seismicity is concentrated along the main branch of the NAF. Splays of the NAF dissect the shear zone into different continental blocks. The largest splay of the NAF was selected to analyze the distribution of movements between the faults delimiting these blocks. Four years of GPS measurements and modeling results indicate that the differential motion between the Anatolian collage and the Eurasian plate along the central part of the NAF is partitioned between fault splays and varies between 18.7 ± 1.6 and 21.5 ± 2.1 mm/yr with the main branch taking ∼90% of the motion. 相似文献
108.
Underground coal mining activities in Kozlu Hard Coal Basin have reached a level affecting ground layers inside the mining seams and the surface just above the mining operations, causing movements in vicinity of the basin. The movements emerge as collapsing in vertical direction and as sliding, curling and bending in horizontal direction and are termed mining subsidence since they exhibit themselves in ground layers and on earth surfaces in mining environments. These mining-induced movements cause damages and destructions on structures inside and on the surface of mining grounds, and the dimensions of these damages depend upon quality of structures and magnitude of movements. In order to contribute toward a solution to these problems and to mitigate the effects arising during and after mining activities, one should identify and investigate damage prone movements and determine the movement–time relationship. Therefore, it is immensely important to observe, investigate, and measure these movements in regions where mining activities take place. This study focuses on the surface movement-related deformations on the engineering structures in the basin such as Kozlu Seaport and some part of the Zonguldak-Kozlu Road. For this reason, subsidence monitoring points were established on the engineering structures in the basin in a geodetic network concept, and three periods of precise leveling and static GPS observations were conducted. Analyzing these two types of geodetic observations, active and residual subsidence effects were determined for both Kozlu Seaport and the Road nearby. 相似文献
109.
110.
S. Bilir Ö. Önal S. Karaali A. Cabrera-Lavers H. Çakmak 《Astrophysics and Space Science》2013,344(2):417-427
We calibrated the absolute magnitudes M V , M J , $M_{K_{s}}$ and M g of red clump stars in terms of colours. M V and M g are strongly dependent on colour, while the dependence of M J and $M_{K_{s}}$ on colour is rather weak. The calibration of the absolute magnitudes M V and $M_{K_{s}}$ is tested on 101 RC stars in the field SA 141. The Galactic model parameters estimated with this sample are in good agreement with earlier studies. 相似文献