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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Geochemical Evaluation And Conceptual Modeling Of Edremit Geothermal Field

Avsar, Ozgur 01 February 2011 (has links) (PDF)
Edremit geothermal field with 42-62 &deg / C discharge temperatures is utilized for space heating. Alternation of permeable and impermeable units created two superimposed aquifers in the area: upper unconfined and lower confined. Water samples from 21 (hot, warm, cold) wells were taken in this study. 8 of these wells penetrate the deeper confined, while 13 penetrate the shallower unconfined aquifer. Geochemical analysis revealed Na+K&ndash / SO4 nature for the hot (&gt / 40&deg / C), Ca&ndash / HCO3 nature for the cold (&lt / 30&deg / C) and Ca&ndash / SO4 nature for the warm (30-40&deg / C) waters. &delta / 18O-&delta / D compositions point to a meteoric origin for all waters, while 14C analyses suggest longer subsurface residence times for the hot, compared to the cold/warm waters. Chemical and isotopic compositions indicate that &ldquo / mixing&rdquo / and &ldquo / water-rock interaction&rdquo / are the possible subsurface processes. When silica and cation geothermometers are evaluated together with fluid mineral equilibria calculations, a 110&deg / C reservoir temperature is expected in the field. Saturation indices indicate potential silica scaling for waters at temperatures lower than discharge temperatures. Hydrogeology of the study area is highly affected by faults. The groundwater is percolated (down to 3 km depth) via deep seated step faults, heated at depth and ascends to surface at the low lands, especially through intersection of buried, mid-graben faults. During its ascent towards surface, geothermal water invades the two superimposed aquifers and mixing between hot and cold waters takes place in the aquifers. Resource assessment studies suggest a 3.45x1013 kJ accessible resource base and 9.1 MWt recoverable heat energy for Edremit geothermal field with 90% probability.
22

Assessment Of Dewatering Requirements For Caldag Nickel Mine In Western Turkey

Cankara, Cigdem 01 October 2011 (has links) (PDF)
The purpose of this study is to assess the dewatering requirements of planned open pit nickel mining at &Ccedil / aldag Site in Western Turkey. Dewatering is required for safe and efficient working conditions and pit wall stability. With this scope, a groundwater model of the study area is developed and used to predict the dewatering rate. The methodology mainly involves data collection, site hydrogeologic characterization and development of conceptual model, followed by construction and use of a groundwater model to predict the dewatering requirements of the mine site. The groundwater flow modeling is carried out using MODFLOW software and the dewatering simulations are carried out using MODFLOW Drain package. The drain cell configuration is determined by pit boundaries and invert elevations of drains corresponded to the bench elevations that will be achieved with respect to the mining schedule. In the transient model runs, monthly time steps were used. Using the outflow from in-pit drain cells, the v monthly dewatering rates are calculated. In order to assess the impacts of the hydraulic conductivity of the laterite on the pit inflow rates, simulations were carried out for different values of hydraulic conductivity of laterites. The predicted flow rate using the calibrated model is 107.54 L/s. A tenfold reduction in the hydraulic conductivity of laterite resulted in three fourths of decrease in the flow rate (24.42 L/s). Consequently, a wide range of flow rates for different hydraulic conductivity values of laterite was calculated. In order to confirm the hydraulic conductivity of laterites in the area, and to obtain a realistic dewatering rate, further pumping tests are needed.
23

Verification Of Empirically Determined Support Systems Of The Kiliclar Highway Tunnel By Numerical Modelling

Celik, Gozde 01 September 2011 (has links) (PDF)
The aim of this study is to determine the geological and geotechnical characteristics of Kili&ccedil / lar Tunnel on Ankara-Kirikkale Highway, to suggest the appropriate support and excavation systems and verify these suggested support systems via numerical modeling. The length of Kili&ccedil / lar Tunnel is 1110 m. The width of tunnel is 16 m, the height is 10 m and the maximum overburden height is 90 m. Since Ankara-Kirikkale Highway consists of 2x3 lanes, the tunnel is designed as a twin tube tunnel. Kili&ccedil / lar Tunnel is planned to be excavated in Gabbro-Diabase and Serpentinite named as Artova Ophiolite Complex. The rock mass is classified by using RMR, Q and NATM classification systems and support systems are determined by using these classification methods. In addition to empirical approaches, 2D finite element analyses are conducted to check the stabilities of seven sections through the tunnel. Results of those analyses pointed out that the support materials determined empirically (4-6 m long bolt with intervals of 1-2 m, 10-20 cm shotcrete, steel sets (wherever required)) are compatible with those recommended after numerical modelling (4-5 m long bolt with intervals of 1.5-2.0 m, 10-20 cm shotcrete, steel sets for entrance and exit sections). Furthermore, the stabilities of the tunnel portals are also studied by numerical analyses and limit equilibrium analyses. Based on the stability analyses performed for both portals, no slope failure is expected at cut slopes with 1H/3V for forehead and for 1H/2V for side slope.
24

Geoarchaeological Investigations Around Kultepe (kayseri)

Omeroglu, Isil 01 September 2011 (has links) (PDF)
The purpose of this study is to investigate the effect of geology on ancient K&uuml / ltepe settlement located in a tectonically active area, namely Sarimsakli basin, shaped by Central Anatolian Fault Zone. Four main data sources used in this study are geological map, digital elevation model (DEM), slip plane and the borehole data. Geological maps are used for the determination of key horizons and the faults shaping the basin. Slip data measured in the field are used to identify the nature of the faults. Borehole data are used for the preparation of Quaternary thickness map and the borehole-to-borehole sections across the basin. Morphology of the area is investigated using the DEM with a particular emphasis on the drainage characteristics of the basin. The analyses have shown that the faults shaping the basin are still active suggesting vertical movements today as well as during the historical period. According to morphological analysis, the basin is drained by a single channel (Karasu river) which is controlled by the western segment of the fault zone. If the fault activates, the channel is elevated resulting in the formation of a lake behind the channel. Accordingly, the present morphological configuration suggests that a water level elevated for 70 m will totally bury K&uuml / ltepe.
25

Lead Isotope Geochemistry Of Pb-zn Deposits From Eastern Taurides, Turkey

Ceyhan, Nuri 01 December 2003 (has links) (PDF)
This study is concerned with the Pb-isotope compositions of galena samples from Pb-Zn occurrences in southern Turkey. The purpose is to i) provide chronologic information for ore deposition, ii) investigate the likely source(s) of lead in ore deposits, and iii) examine the possible control of tectonic setting and crustal basement on Pb-isotope compositions. The data used in the study belongs to the deposits located in Taurides (Zamanti, KahramanmaraS, Malatya, Elazig, Bitlis), with additional data from Nigde Massif and Hakkari Area. The mineralizations are dominantly carbonate-hosted Pb-Zn deposits formed as fracture and karst fillings and, in some places, parralel to bedding. Ore minerals are mainly Zn-oxides and minor Zn, Pb-sulphides. The Pb-isotope compositions, as evaluated in terms of their configuration with respect to reference crustal growth curves and reference isochrons on conventional Pb-isotope diagrams, point to U/Pb ratios greater than average crustal values (and close to the Western Mediterranean Crustal Growth Curve) for all the deposits, indicating upper crustal source for Pb. However, some of the deposits (AfSin-KahramanmaraS / Oreks, D&uuml / ndarli, AgcaSar and skarn type deposits to the south of &Ccedil / adirkaya in Zamanti (Kayseri-Adana) / Keban-Elazig) appear to have magmatic inputs in their genesis. Relatively old deposits are likely Paleozoic (Cafana-Malatya and T&uuml / rksevin-KahramanmaraS), Late Paleozoic-Early Mesozoic (Kalek&ouml / y-Zamanti) and Mesozoic (Hakkari) in age. The rest of the deposits (most of the occurrences in Zamanti, Nigde, KahramanmaraS, Elazig and Bitlis) are likely of Cenozoic age. The Pb-isotope compositions are, in general, similar to those from other occurrences in the Mediterranean Belt.
26

Joint Analysis In The Rock Settlements Of Cappadocia

Sevindi, Gokhan 01 December 2003 (has links) (PDF)
This thesis attempts to seek a relationship between the joints developed in the ignimbrites and the rock settlements carved in the same units. Orientation of rooms, directions of walls and joints (both in the rooms and in the field) are input data used in the study. Two sites in Cappadocia (Eskig&uuml / m&uuml / Sler and &Ccedil / anlikilise) are selected to investigate the relationship. Both sites are carved within the same ignimbrite (Kizilkaya) and are located on the south-southeastern slopes of the ignimbrite scarp. Measurements taken from 61 rooms of the former and 27 rooms of the latter are analyzed for the room and joint directions, joint locations in the room and joint densities both in the rooms and in the field. Conclusions derived from the analyses are: 1) The rooms are oriented oblique to joint strike to get the maximum sunlight, 2) Joint directions in the rooms strike in one single direction and greatly differ from the field joint directions, 3) Density of the room joints is less than the field joints indicating that joint spacing is an important factor in the selection of sites, 4) Joints in the Eskig&uuml / m&uuml / Sler sites are concentrated towards the margins of the room while an opposite observation is made for the &Ccedil / anlikilise site, 5) Total length of joints in the largest rooms are relatively shorter.
27

Dewatering Plan And Prediction For Pit Lake Flooding For A Quarry Site

Duru, Uygar 01 April 2004 (has links) (PDF)
This study presents the dewatering assessment of a marl quarry with the future pit lake level predictions. The objectives of the study were / (1) to determine the dewatering requirements that would allow for the continuation of the quarrying operations in the deeper parts of the quarry, (2) to design an optimum dewatering system compatible with the site hydrogeological conditions and quarrying plans, (3) to assess the environmental impacts of dewatering on the local water (surface and ground water) resources and users, and (4) to predict the future pit lake level and flooding period for different meteorological conditions. To these ends, previous investigation reports and maps have been compiled and reviewed and field investigations have been conducted. During the field investigations pumping and observation wells were drilled and installed. After installation, in situ tests were conducted to determine aquifer parameters. It was found that properties of the material is conducive to the dewatering activities that will be necessary for the deepening of the open pit of the marl quarry. A groundwater model was developed based on the field data gathered. According to this model dewatering trenches will be needed to dewater the pit. The model predicted that operating these dewatering trenches would create an elongated cone of depression that will sufficiently lower the groundwater table so that quarrying operations can proceed. Lowering of the water table may produce a negative impact on groundwater resources within the aerial extent of the cone of depression. This potentially negative impact was investigated with model simulations and has been found that the impact to the resources would be negligible. Three scenarios were evaluated as possible dewatering discharge disposal solutions. The preferred scenario included the discharge of this water to the stream, which is flowing on the western side of the quarry. The pit will start to fill with water immediately after the dewatering operations stopped. In order to predict the pit lake flooding period and final lake elevation, pit lake hydrologic model was developed. The simulations predict that the final pit lake elevation would be at 991 m. The pit lake will rise to this level at approximately 72 years after closure.
28

Landfill Site Selection By Using Geographic Information Systems

Sener, Basak 01 September 2004 (has links) (PDF)
One of the serious and growing potential problems in most large urban areas is the shortage of land for waste disposal. Although there are some efforts to reduce and recover the waste, disposal in landfills is still the most common method for waste destination. An inappropriate landfill site may have negative environmental, economic and ecological impacts. Therefore, it should be selected carefully by considering both regulations and constraints on other sources. In this study, candidate sites for an appropriate landfill area in the vicinity of Ankara are determined by using the integration of Geographic Information Systems and Multicriteria Decision Analysis. For this purpose, sixteen input map layers including topography, settlements (urban centers and villages), roads (Highway E90 and village roads), railways, airport, wetlands, infrastructures (pipelines and power lines), slope, geology, land use, floodplains, aquifers and surface water are prepared and two different MCDA methods (Simple Additive Weighting and Analytic Hierarchy Process) are implemented in GIS environment. Comparison of the maps produced by these two different methods shows that both methods yield conformable results. Field checks also confirm that the candidate sites agree well with the selected criteria.
29

Monitoring Of Chemical And Isotopic Compositions Of Geothermal Waters Along The North Anatolian Fault Zone

Suer, Selin 01 September 2004 (has links) (PDF)
This study aims to determine the chemical (anion-cation) and isotopic compositions (&amp / #948 / 18O-&amp / #948 / D-3H) of the geothermal waters along the North Anatolian Fault Zone (NAFZ) and highlight any possible seismicity-induced temporal variations during the course of two years (2002-2003) monitoring programme. The geothermal sites are alligned along a 800 km transect of the NAFZ and are, from west to east, Yalova, Efteni, Bolu, Mudurnu, Seben, KurSunlu, Hamam&ouml / z&uuml / , G&ouml / zlek and ReSadiye. The thermal waters of NAFZ are dominantly Na-HCO3, whereas the cold waters are dominantly Ca-HCO3 in character. The highest temperature (72.3&amp / #61616 / C) is recorded in Seben. The hot waters are slightly acidic to alkaline in character with pH values ranging between 5.92-7.97, while the cold waters are comparatively more alkaline with pH values between 6.50-8.83. Both hot and the cold waters are meteoric in origin. The hot waters have lower &amp / #948 / 18O-&amp / #948 / D and tritium values suggesting higher recharge altitudes for aquifers and longer residence times for waters, respectively, in the geothermal system (compared to the cold waters). Temporal variations are detected in both ionic and isotopic compositions of the cold and the hot waters, and these reflect seasonal variations for cold and seismicity-induced variations for hot waters. Although no major earthquakes (M&gt / 5) occurred along the NAFZ during the monitoring period, temporal variations recorded in Cl and 3H, and to a lesser extent in Ca and SO4 contents seem to correlate with seismicity along the NAFZ. In this respect, Yalova field deserves the particular attention since seismicity induced variations were better recorded in this field.
30

Genesis Of The Karaali (ankara, Turkey) Fe-cu Sulfide Mineralization

Imer, Ali 01 January 2006 (has links) (PDF)
With the closure of Neo-Tethys in the Early Tertiary, oceanic crustal material was accreted along the izmir-Ankara-Erzincan Suture Zone. The Ankara m&eacute / lange developed within this suture zone and contains Cretaceous ophiolitic fragments, some of which host significant Fe-Cu sulfide mineralization. Such mineralization is observed as massive to disseminated pyrite-chalcopyrite hosted by pillow to massive basalts in a dismembered and tectonically imbricated ophiolite block near Karaali, Ankara. Basaltic host rocks lack most of their primary mineral assemblages and textural relationships. As a consequence of greenschist-facies metamorphism and hydrothermal alteration, the basalts were strongly albitized and propylitized prior to late-stage argillic alteration, which is proximal to the main mineralized zone. Sulfide mineralization occurs in a massive sulfide lens and laterally extensive, 10-meter-thick zone of anastomosing quartz-sulfide veins. Other than pyrite and chalcopyrite, bornite, covellite and sphalerite also occur as minor sulfide phases, and the source of sulfur is determined to have been magmatic on the basis of 34S isotope analyses. A series of geochemical analyses suggest that the basaltic host rocks formed within a subduction-related tectonic setting, and the mineralization is thought to have formed during a medium-temperature hydrothermal event which was followed by another later period of low-temperature hydrothermal activity. Field, petrographical and geochemical evidence show that the Karaali Fe-Cu mineralization is genetically correlative with the Cyprus and K&uuml / re massive sulfide deposits, and may be classified as a Cyprus-type massive sulfide deposit.

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