Intermediate sulfidation epithermal gold-base metal deposits in Tertiary subaerial volcanic rocks,Sahinli/Tespih Dere (Lapseki/Western Turkey)

Gold in the Sahinli and Tespih Dere intermediate sulfidation gold-base metal deposits in Western Turkey occurs in relatively deep epithermal quartz veins along with base metal minerals which have epithermal textures, including plumose quartz, vug infills, comb and cockade textures and matrix-supported milled breccias. The total sulfide content of the veins in the area is variable ranging from < 1% to 60% and is dominated by pyrite, galena, sphalerite and chalcopyrite. Sphalerite is Fe-poor (0.6 to 1.4 mol% FeS). Minor amounts of Ag-rich tetrahedrite are present. Primary hydrothermal alteration minerals include illite/muscovite, mixed-layer illite/smectite (11.6 Å) and clinochlore towards the east and, alunite, dickite/nacrite and pyrophyllite towards the west at Sahinli; major illite/muscovite and dickite occur at Tespih Dere and Sarioluk, respectively.Fluid inclusions in main-stage quartz at Sahinli are only liquid-rich, with homogenization temperatures ranging from 220 to 322 °C and the majority of T_h values between 250 and 300 °C. Salinity ranges from 4.3 to 6.9 wt.% NaCl equiv. First ice-melting temperatures (T_mf) between ?24.5 and ?19.0 °C indicate that the fluids were dominated by NaCl – H₂O during mineralization. The relatively higher average T_h at the Tespih Dere deposit (295 °C) is attributed to a relatively deeper level of exposure.Calculated δ¹⁸O values indicate that ore-forming hydrothermal fluids in the study area had δ¹⁸O_H2O ranging from + 1.1 to + 9.7‰ (average = 3.8‰), strongly ¹⁸O-enriched compared with present-day hydrothermal meteoric water in the area (δ¹⁸O = ?8.5‰). δD values of fluid inclusions in quartz range from ?58 to ?93‰ and δD values of clay minerals and alunite from ?40 to ?119‰. δD values from intermediate argillic alteration (average = ?68‰) in the study area are very similar to δD values of the present-day local geothermal system (average δD = ?54‰) whereas δD values from advanced-argillic alteration (average δD = ?33‰) are very different from the present-day local geothermal system.The δ³⁴S values in samples from the Sahinli and Tespih Dere deposits average ?2.9‰ for pyrite; ?3.3‰ for chalcopyrite; ?5.4‰ for sphalerite and ?7.6‰ for galena. These data are consistent with derivation of the sulfur from either igneous rocks or possibly from local wallrock.     

One-dimensional consolidation under haversine repeated loading with rest period

Presented in this paper is a study of the one-dimensional consolidation process under haversine repeated loading with and without rest period. The analysis was carried out using a hybrid coupled, analytical and numerical implicit finite difference technique. The rate of imposition of excess pore-water pressure was determined analytically, and the remaining part of the governing differential equation was solved numerically. The clay deposit considered was a homogeneous clay layer with permeable top and/or impermeable bottom hydraulic boundary conditions with constant coefficients of permeability and of consolidation. The study reveals that although the loading function is positive for all times, the excess pore-water pressure at the base of the clay deposit with permeable top and impermeable bottom oscillates with time reaching a ‘steady state’ after few cycles of loading depending on whether there is a rest period or not. An increase in the rest period causes a decrease in the number of cycles required to achieve the steady state. The paper shows also that the rest period in the haversine repeated loading decelerates the consolidation process. Similarly, the paper reveals that the effective stress at the bottom of the clay layer with permeable top and impermeable bottom increases with time but showing mild fluctuations that do not change the sign. The maximum positive effective stress achieved depends on the rest period of the haversine repeated loading. A haversine repeated loading without a rest period gives the highest value for the positive effective stress.     

Water quality and hydrogeochemical characteristics of the River Buyukmelen,Duzce, Turkey

The River Buyukmelen is located in the province of Duzce in northwest Turkey and its water basin is approximately 470 km². The Aksu, Kucukmelen and Ugursuyu streams flow into the River Buyukmelen. It flows into the Black Sea with an output of 44 m³ s⁻¹. The geological succession in the basin comprises limestone and dolomitic limestone of the Yılanlı formation, sandstone, clayey limestone and marls of the Akveren formation, clastics and volcano‐clastics of the Caycuma formation, and cover units comprised of river alluvium, lacutrine sediments and beach sands. The River Buyukmelen is expected to be a water source that can supply the drinking water needs of Istanbul until 2040; therefore, it is imperative that its water quality be preserved. The samples of rock, soil, stream water, suspended, bed and stream sediments and beach sand were collected from the Buyukmelen river basin. They were examined using mineralogical and geochemical methods. The chemical constituents most commonly found in the stream waters are Na⁺, Mg²⁺, SO²⁻₄, Cl⁻ and HCO₃⁻ in the Guz stream water, Ca²⁺ in the Abaza stream water, and K⁺ in the Kuplu stream water. The concentrations of Na⁺, K⁺, Ca²⁺, Mg²⁺, SO²⁻₄, HCO⁻₃, Cl⁻, As, Pb, Ni, Mn, Cr, Zn, Fe and U in the Kuplu and Guz stream waters were much higher than the world average values. The Dilaver, Gubi, Tepekoy, Maden, Celik and Abaza streams interact with sedimentary rocks, and the Kuplu and Guz streams interact with volcanic rocks. The amount of suspended sediment in the River Buyukmelen in December 2002 was 120 mg l⁻¹. The suspended and bed sediments in the muddy stream waters are formed of quartz, calcite, plagioclase, clay (kaolinite, illite and smectite), muscovite and amphibole minerals. As, Co, Cd, Cr, Pb, Ni, Zn and U have all accumulated in the Buyukmelen river‐bed sediments. The muddy feature of the waters is related to the petrographic features of the rocks in the basin and their mineralogical compositions, as most of the sandstones and volcanic rocks (basalt, tuffite and agglomerate) are decomposed to a clay‐rich composition at the surface. Thus, the suspended sediment in stream waters increases by physical weathering of the rocks and water–rock interaction. Owing to the growing population and industrialization, water demand is increasing. The plan is to bring water from the River Buyukmelen to Istanbul's drinking‐water reservoirs. According to the Water Pollution Regulations, the River Buyukmelen belongs to quality class 1 based on Hg, Cd, Pb, As, Cu, Cr, Zn, Mn, Se, Ba, Na⁺, Cl⁻, and SO²⁻₄; and to quality class 3 based on Fe concentration. The concentration of Fe in the River Buyukmelen exceeds the limit values permitted by the World Health Organization and the Turkish Standard. Because water from the River Buyukmelen will be used as drinking water, it will have an adverse effect on water quality and humans if not treated in advance. In addition, the inclusion of Mn and Zn in the Elmali drinking‐water reservoir of Istanbul and Fe in the River Buyukmelen water indicates natural inorganic contamination. Mn, Zn and Fe contents in the waters are related to geological origin. Moreover, the River Buyukmelen flow is very muddy in the rainy seasons and it is inevitable that this will pose problems during the purification process. Copyright © 2005 John Wiley & Sons, Ltd.     

Failure and flow development of a collapse induced complex landslide: the 2005 Kuzulu (Koyulhisar, Turkey) landslide hazard

Koyulhisar located in a slope of hilly region and constructed in the side of a mountain along the North Anatolian Fault Zone is frequently subject to landslides. A catastrophic landslide occurred on the morning of 17 March 2005 in the North of the Kuzulu district of Koyulhisar (Sivas, Turkey). This landslide caused widespread loss of life, and damage to buildings, and lifelines. Fifteen people were dead and five were injured, 21 houses and a minaret were covered and damaged severely. The case study presented in this paper describes and analyses the results of the detailed surveys of an interesting landslide in Kuzulu district of Koyulhisar (Sivas, Turkey), based on field and laboratory measurements and monitoring of the slide area. Landslide initiated as a collapse, and developed into debris avalanches in the valley. This phenomenon caused a disaster in the Kuzulu district. The importance of this landslide in particular has been recognized both in terms of its consequence for the people and structures and in terms of its role in allowing an understanding of process and properties of landslide triggered by a collapse in limestone karst. In view of the potential for such events to occur again in this area and environs, understanding of the failure mechanism is very crucial.     

Monitoring the tectonic plate movements in Turkey based on the national continuous GNSS network

In recent decades, the space geodesy has been applied to the areas such as transportation, infrastructure planning, navigation, etc. Among them, the precise positioning at the Global Navigation Satellite System (GNSS) stations yields better view in the understanding of the crustal deformation that requires global-scale measurements. There have been numerous studies examining the data process of continuous GNSS observations in the field of earth monitoring. More recently, GNSS stations established for continuously operating reference station networks have been beneficial resources in the tectonic plate-monitoring studies in lieu of campaign-type observations. However, this requires that the Continuously Operating Reference Station (CORS) should be established on stable structures acting like foundations and requires investigation of the long-term repeatability time series. This study aims to introduce recently established national CORS network, named CORS-TR, covering the entire Turkey and Northern Cyprus, and to explain the process of the long-term data obtained from the network on the characteristics of the tectonic plate movement within the area. The results of the CORS-TR data process present a great potential of using continuously operating reference stations not only in real-time kinematic applications of conventional geodesy studies but also in detecting and monitoring the crustal deformations of those that are crucial in earthquake-prone areas like Turkey. Since the findings are computed from the results of the all permanent stations of CORS-TR network, this study also examines the GNSS observation quality of the network for the given time interval. One of the major conclusions of the data process conducted in the study displays that the CORS-TR stations established on the carefully selected large and low-rise existing building had been more stable than the stations on the ground which have been subjected to soil settlement since the construction.     

Reservoir-system simulation and optimization techniques

Reservoir operation is one of the challenging problems for water resources planners and managers. In developing countries the end users are represented by the water sectors in most parts and conflict over water is resolved at the agency level. This paper discusses an overview of simulation and optimization modeling methods utilized in resolving critical issues with regard to reservoir systems. In designing a highly efficient as well as effective dam and reservoir operational system, reservoir simulation constitutes one of the most important steps to be considered. Reservoirs with well-functional and reliable optimization models require very accurate simulations. However, the nonlinearity of natural physical processes causes a major problem in determining the simulation of the reservoir’s parameters (elevation, surface-area, storage). Optimization techniques have shown high efficiency when used with simulation modeling and the combination of the two methods had given the best results in the reservoir management. The principal concern of this review study is to critically evaluate and analyze simulation, optimization and combined simulation–optimization modeling approach and present an overview of their utility in previous studies. Inferences and suggestions which may assist in improving quality of this overview in the future are provided. These will also enable future researchers, system analysts and managers to achieve more precise optimal operational system.     

Dissolved Nutrient Distributions in Groundwater in the Mediterranean Coastal Plains – the Case of Silifke,Turkey

Total carbon, nitrogen, and phosphate parameters were studied for the first time in the groundwater in the Silifke coastal plain, which is a RAMSAR site in Turkey. Seasonal variations of these parameters in the plain were examined based on groundwater data collected from 21 wells during the winter, spring, summer, and fall seasons. Total dissolved organic carbon (DOC), inorganic carbon (DIC), inorganic phosphate (DIP), inorganic nitrogen (DIN), and total alkalinity (TAlk) average values in the groundwater were low in all seasons (<2.2 mg/L for DOC; <54 mg/L for DIC; <0.06 mg/L for DIP; <1.5 mg/L for DIN; <232 mg/L for TAlk). The results showed a strong relationship between DIC and as expected. The results indicate that the content of these parameters in the groundwater of Silifke coastal plain pose no or little risk at present. However, computed Langelier Saturation Index (LSI) values indicated that the groundwater has a tendency to form scale and CaCO₃ precipitation may occur.     

Levels of Cd,Cu, Pb and V in marine sediments in the vicinity of the Single Buoy Moorings (SBM3) at Mina Al Fahal in the Sultanate of Oman

Recently in the Sultanate of Oman, there has been a rapid surge of coastal developments. These developments cause metal contamination, which may affect the habitats and communities at and near the coastal region. As a result, a study was conducted to assess the level of metal contamination and its impact on the marine sediments in the vicinity of the Single Buoy Moorings 3 (SBM3) at Mina Al Fahal in the Sultanate of Oman. Marine subtidal sediment samples were collected from six different stations of the SBM3 for the period ranging from June 2009 to April 2010. These samples were then analyzed for their level and distribution of the heavy metals of cadmium (Cd), copper (Cu), lead (Pb) and vanadium (V). Overall, low concentrations of all four heavy metals were measured from the marine sediments, indicating that the marine at SBM3 is of good quality.     

Level of environmental awareness towards depletion of the ozone layer among distributors and consumers in the solvent sector: a case study from Oman

The main objective of this study was to assess the level of environmental awareness among ozone depleting substances (ODSs) distributors and consumers in the solvent sector in the Arabian Gulf country of Oman. The focus was on ozone depleting substances that are usually released in cleaning, formulation solvent and process agent processes (CFC-113, 1,1,1-trichloroethane, CTC-carbon tetrachloride). A comparison between importers and end-users of ODSs and the public in relation to environmental awareness regarding ozone layer depletion was carried out. The results showed that environmental knowledge about ozone layer depletion was higher among the importers and end-users of ODSs than amongst the public. Nevertheless, there were much smaller differences in environmental attitudes and behaviors between the importers and end-users of ODSs, and the public toward ozone layer depletion. This showed that the public in the case study country has a very positive attitudes and behaviors towards the environment.     

Electrical resistivity imaging and dye tracer test for the estimation of water leakage paths from reservoir of Akdeğirmen Dam in Afyonkarahisar,Turkey

The seepage occurrence from the reservoir on the right bank of the Akde?irmen Dam located in Afyonkarahisar province in the Turkey has been investigated. When the reservoir began to fill with water, a large amount of water seepage occurred at the dam. The seepage developed at the base of the spillway and the right downstream slope of the dam. The various attempts have been made to reduce the seepage using grouting. Although the additional grouting operations was reduced the seepage at the base of the spillway, there has not been a reduction in seepage at the water outlet location at the downstream slope. Electrical resistivity measurements along the eight lines with the dipole–dipole array and dye tracer tests were performed in order to identify the seepage locations. The interpretation of electrical resistivity data showed the distribution of strata and the seepage zone along the right downstream of the dam. Groundwater flow rates calculated from dye tests indicated that there is an excessive seepage south-eastwardly on the downstream slope of the dam. Integrated interpretation of resistivity data and dye tests indicate that the seepage paths are in the direction from NW to E and SE.