排序方式： 共有27条查询结果，搜索用时 172 毫秒
11.
12.
Mineral resource evaluation requires defining geological rock-type domains. The traditional simulation methods have serious limitations for applications to large numbers of domains, which have complex contact relations. Plurigaussian simulation is an effective method which can be applied, in a simple way, to any number of domains, using both local and global geological information to infer the distributions of rock types. This work not only presents the application of the plurigaussian simulation method to the Balya lead-zinc deposit, but also assesses the spatially varying rock type proportions, and accounts for uncertainties between them. These parameters are extremely important for mining deposits, since the mineralizations of interest generally occur only in certain rock types. Furthermore, being able to model the different geological rock types is vital to good mine operations, production planning, and management. The results indicate that the plurigaussian method correctly reproduces the different orientations of the individual rock types, as seen in drill holes, and the proportion of each rock type, even if this varies in space. 相似文献
13.
The effectiveness of coagulation (at pH values of 6, 7.5, and 9), flocculation (at pH 9), and coagulation plus flocculation (at pH 9) on turbidity removal from natural stone (travertine) processing wastewaters (NSPW) were examined by applying classical sedimentation tests. FeCl3·6 H2O, AlCl3, and Al2(SO4)3·16 H2O were used as coagulants and a polyacrylamide based anionic polymer was used as the flocculant. In this way, it was found that the coagulation method alone was not sufficient to purify NSPW, whereas flocculation and coagulation plus flocculation methods provided superior purification. Among the coagulants used, AlCl3 gave the best result in terms of turbidity removal by coagulation from NSPW at pH 6 and 9, whereas the turbidity removal performances of the three coagulants were almost identical at pH 7.5. In addition, relatively low pH (i. e., pH 6) improved the purification performance of all coagulants. During coagulation of NSPW at pH 6, a charge neutralization mechanism played a decisive role in turbidity removal. However, in neutral (pH 7.5) and slightly basic (pH 9) media, a sweep coagulation mechanism was predominant. For flocculation of NSPW, the basic mechanism comprised of polymer bridging. 相似文献
14.
Faruk?AydinEmail author Axel?K.?Schmitt Wolfgang?Siebel Mustafa?S?nmez Yal??n?Ersoy Abdurrahman?Lermi Kadir?Dirik Robert?Duncan 《Contributions to Mineralogy and Petrology》2014,168(5):1078
The late Neogene to Quaternary Cappadocian Volcanic Province (CVP) in central Anatolia is one of the most impressive volcanic fields of Turkey because of its extent and spectacular erosionally sculptured landscape. The late Neogene evolution of the CVP started with the eruption of extensive andesitic-dacitic lavas and ignimbrites with minor basaltic lavas. This stage was followed by Quaternary bimodal volcanism. Here, we present geochemical, isotopic (Sr–Nd–Pb and δ18O isotopes) and geochronological (U–Pb zircon and Ar–Ar amphibole and whole-rock ages) data for bimodal volcanic rocks of the Ni?de Volcanic Complex (NVC) in the western part of the CVP to determine mantle melting dynamics and magmatic processes within the overlying continental crust during the Quaternary. Geochronological data suggest that the bimodal volcanic activity in the study area occurred between ca. 1.1 and ca. 0.2 Ma (Pleistocene) and comprises (1) mafic lavas consisting of basalts, trachybasalts, basaltic andesites and scoria lapilli fallout deposits with mainly basaltic composition, (2) felsic lavas consisting of mostly rhyolites and pumice lapilli fall-out and surge deposits with dacitic to rhyolitic composition. The most mafic sample is basalt from a monogenetic cone, which is characterized by 87Sr/86Sr = 0.7038, 143Nd/144Nd = 0.5128, 206Pb/204Pb = 18.80, 207Pb/204Pb = 15.60 and 208Pb/204Pb = 38.68, suggesting a moderately depleted signature of the mantle source. Felsic volcanic rocks define a narrow range of 143Nd/144Nd isotope ratios (0.5126–0.5128) and are homogeneous in Pb isotope composition (206Pb/204Pb = 18.84–18.87, 207Pb/204Pb = 15.64–15.67 and 208Pb/204Pb = 38.93–38.99). 87Sr/86Sr isotopic compositions of mafic (0.7038–0.7053) and felsic (0.7040–0.7052) samples are similar, reflecting a common mantle source. The felsic rocks have relatively low zircon δ18O values (5.6 ± 0.6 ‰) overlapping mantle values (5.3 ± 0.3 %), consistent with an origin by fractional crystallization from a mafic melt with very minor continental crustal contamination. The geochronological and geochemical data suggest that mafic and felsic volcanic rocks of the NVC are genetically closely related to each other. Mafic rocks show a positive trend between 87Sr/86Sr and Th, suggesting simultaneous assimilation and fractional crystallization, whereas the felsic rocks are characterized by a flat or slightly negative variation. High 87Sr/86Sr gneisses are a potential crustal contaminant of the mafic magmas, but the comparatively low and invariant 87Sr/86Sr in the felsic volcanics suggests that these evolved dominantly by fractional crystallization. Mantle-derived basaltic melts, which experienced low degree of crustal assimilation, are proposed to be the parent melt of the felsic volcanics. Geochronological and geochemical results combined with regional geological and geophysical data suggest that bimodal volcanism of the NVC and the CVP, in general, developed in a post-collisional extensional tectonic regime that is caused by ascending asthenosphere, which played a key role during magma genesis. 相似文献
15.
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
16.
Arabian Journal of Geosciences - The uniaxial compressive and tensile strength of rocks are crucial parameters in the design stage of geotechnical structures. However, direct determination of these... 相似文献
17.
18.
&#x;nan Ulusoy Philippe Labazuy Erkan Aydar Orkun Ersoy Evren ubuku 《Journal of Volcanology and Geothermal Research》2008,174(4):269-283
Plio-Quaternary volcanism played an important role in the present physical state of Eastern Anatolia. Mount Nemrut, situated to the west of Lake Van is one of the main volcanic centers in the region, with a spectacular summit caldera 8.5 × 7 km in diameter. The most recent eruptions of the volcano were in 1441, 1597 and 1692. Nemrut Lake covers the western half of the caldera; it is a deep, half-bowl-shaped lake with a maximum depth of 176 m. Numerous eruption centers are exposed within the caldera as a consequence of magma–water interaction. Current activity of Nemrut caldera is revealed as hot springs, fumaroles and a small, hot lake.Self-potential and bathymetric surveys carried out in the caldera were used to characterize the structure of the caldera and the associated hydrothermal fluid circulation. In addition, analyses based on digital elevation models and satellite imagery were used to improve our knowledge about the structure of the caldera. According to SP results, the flanks of the volcano represent “the hydrogeologic zone”, whereas the intra-caldera region is an “active hydrothermal area” where the fluid circulation is controlled by structural discontinuities. There is also a northern fissure zone which exhibits hydrothermal signatures. Nemrut caldera collapsed piecemeal, with three main blocks. Stress controlling the collapse mechanism seems to be highly affected by the regional neotectonic regime. In addition to the historical activity, current hydrothermal and hydrogeologic conditions in the caldera, in which there is a large lake and shallow water table, increase the risk of the quiescent volcano. 相似文献
19.
We present the volcanic ash and tsunami record of the Minoan Late Bronze Age Eruption of Santorini (LBAES) in a distal setting in southwestern Turkey. In one of the drilled cores at the Letoon Hellenic antique site on Eşençay Delta, we encountered a 4 cm thick tephra deposit underlain by 46 cm thick tsunami-deposited sand (tsunamite), and an organic-rich layer that we 14C dated to 3295 ± 30 bp or 1633 bc. The relationship between Santorini distal volcanic ash and underlying tsunamite is described and interpreted. LBAES occurred in four main phases: (1) plinian; (2) phreatomagmatic; (3) phreatomagmatic with mudflows; and (4) ignimbritic flows and co-ignimbrite tephra falls. In this study, we aim to understand which eruptive phases generate distal ash during the Minoan eruptive sequence by examining the 3D surface morphology of ash formed by different fragmentation processes. To that end, we used numerous statistical multivariates, 3D fractal dimension of roughness, and a new textural parameter of surface area-3D/plotted area-2D to characterise the eruption dynamics. Based on ash surface morphologies and the calculated statistical parameters, we propose that that distal ash is represented by a single layer composed of well-mixed (coarse to fine) magmatic and phreatomagmatic ash. 相似文献
20.
Aksel Ersoy 《The Professional geographer》2016,68(1):138-148
This article examines the distribution of the headquarters of top 500 large industrial enterprises in Turkey. It contributes to the knowledge of economic geography by examining regional clusters of headquarters activity in Turkey. As a country, Turkey's corporations have not been extensively analyzed or integrated into the international economic geography literature especially given the fact that headquarters activities in general are important but understudied in the literature of geography. This study therefore extends the corporate literature further in an international dimension, a priority that has been noted as important in the headquarters literature of geography. It argues that not only does the spatial organization of corporations remain important in urban systems but also that they are linked to the dynamics of local and regional economies within developing countries. It shows that various Turkish cities have distinctive internal structures comprising agglomerations of different industries. Although some of these industries are better performing in big cities, the majority of the cities in the top 500 large enterprises list underperform on average. 相似文献