Gültekin Tarcan - Academia.edu (original) (raw)

Papers by Gültekin Tarcan

Environmental geology, Dec 1, 2002

Boron concentrations of the CO 2-rich thermal waters in western Anatolia have a wide range of 1-6... more Boron concentrations of the CO 2-rich thermal waters in western Anatolia have a wide range of 1-63 mg/l. Cl/B molal ratios of high temperature waters (>150°C) have low values ranging from 1 to 10. In low-temperature thermal waters (<150°C), with the exception of samples that have some seawater, Cl/B ratios range from 2 to 88. The positive correlation between HCO 3 and B values for thermal waters means that B concentrations in thermal waters are also associated with the dissolution of carbonates. In addition to the water-rock interaction, boron in thermal waters is probably controlled by the contribution of B by degassing of magma intrusives. Sericite, illite and tourmaline minerals, which are abundant in Menderes Massif rocks, are considered to be the main reason for the high boron contents. High B concentrations of thermal waters causes environmental problems in groundwaters and surface waters in some agricultural areas of western Anatolia. Re-injection of thermal waters to the reservoir is the best way to dispose of the geothermal wastewater and prevent contamination problems.

Arabian Journal of Geosciences, Dec 1, 2017

The town of Salihli is situated in Gediz Graben in the western Anatolia. This region is important... more The town of Salihli is situated in Gediz Graben in the western Anatolia. This region is important in terms of industry, mining, geothermal energy, water sources, and agricultural production. Geothermal flow and anthropogenic activities in Salihli threaten the surrounding environment due to the contamination of cold groundwater, surface water, and soil. The goal of the present study is to determine the environmental effects of the geothermal and anthropogenic activities in Salihli on soil, stream sediments, and water. Stream sediments and farm soil have been contaminated by substances derived from geothermal and industrial effluents. To this end, the quality review of the water was completed and the heavy metal levels in stream sediment samples were measured to determine the extent of contamination. The elements As, B, Br, Fe, and Ni are the major contaminants present in surface water and groundwater in the study area. The concentrations of these elements excess tolerance limits of international water standards. Gibbsite, K-mica, kaolinite, sepiolite, halite, sulfur, willemite, and Pb(OH) 2 might be precipitated as scales at low temperatures on the soil; this could be interpreted as a resultant from soil contamination. The concentrations of 17 elements (As,

Applied Geochemistry, 2004

Metamorphic rocks host the majority of the thermal waters of the Emet area. Only Dereli springs a... more Metamorphic rocks host the majority of the thermal waters of the Emet area. Only Dereli springs are hosted by nonmetamorphic carbonates and ophiolitic rocks. The carbonated rocks of the lower parts of the Neogene sequence are also secondary reservoir rocks. The measured surface temperatures of thermal waters are between 33 and 54 C. Most of the thermal waters are characterized as Ca-Mg-SO 4-HCO 3 type although there are a few Ca-Na-HCO 3 , Na-Ca-SO 4 and Ca-Mg-HCO 3 waters. Calcium concentrations in the thermal waters are 89-354 mg/kg. High SO 4 contents of the thermal waters (up to 1309 mg/kg) are related to rocks and minerals in the Red Unit below the Emet borate deposits. Although the SO 4 concentrations are high and SO 4 is the major anion, gypsum and anhydrite are undersaturated for all of the thermal waters indicating that dissolution of SO 4 is still taking place in the reservoir. Thermal waters are oversaturated at outlet conditions with respect to calcite, chalcedony, dolomite and quartz. According to the activity diagrams thermal waters are likely to form illite as an alteration product in the reservoir and Ca and Mg contents are controlled by exchange with smectite. Reservoir temperatures obtained by silica geothermometers and assessments of the saturation states of minerals are more appropriate for Emet geothermal waters. Assessments of the various geothermometers suggest that reservoir temperature is around 75-87 C.

Environmental Earth Sciences, Jun 1, 2016

The study area is located in the center of the Karaburun Peninsula, Turkey, where several karstic... more The study area is located in the center of the Karaburun Peninsula, Turkey, where several karstic springs discharge near the coast 0–2 m above the sea level. The most important discharge points are the Ildırı and Gerence springs. Groundwater obtained from Ildırı springs and several drill wells provide water to the region during the summer periods. The electrical conductivity values are between 1900 and 3900 μS/cm. Springs are slightly salty and are not used directly as drinking water. Salinity was observed in the spring waters under natural flow conditions. The salinity values of the drillings and springs were measured in dry and wet seasons. Spring waters have conductivity values between 3000 and 4000 μS/cm. Preliminary surveys reveal that seawater contribution to Ildırı springs is 6.5 % maximum. Gerence spring waters discharge to the surface from a region very close to the sea. The dominant cation is Na, and the dominant anion is Cl. Conductivity values were between 7000 and 13,000 μS/cm. Gerence spring waters discharge to the sea with seawater contributions ratios between 8.5 and 20.3 % depending on the seasonal changes. While some spring waters discharge 0.5–1.0 m above sea level, the rest of them discharge directly into the sea. Salinization of Gerence spring water is higher than the other springs.

Applied Geochemistry, Oct 1, 2009

Acid mine drainage, downstream transport of metal-rich water and sediment runoff adversely effect... more Acid mine drainage, downstream transport of metal-rich water and sediment runoff adversely effect the environment surrounding the Halıköy Hg mine. This study focuses on the environmental effects of the Halıköy Hg mine on soil, stream sediment and water because the area is used for agricultural purposes. Stream sediment and farming soil have been polluted by contaminants derived from the mine. The effects of Hg mining and the distribution of contaminants in soil and stream sediment were evaluated by calculation of enrichment factors (EFs) which indicated enrichments for As, Hg, Sb and Pb. Other metals Cd, Co, Cr, Cu, Fe and Zn show moderate enrichment in soil close to the mine. EFs indicate soil contamination in the order of: Hg > As > Sb > Ni > Co > Cu > Fe > Zn > Cr > Pb > Cd. The greatest contamination was found near mine wastes, decreasing with increasing distance from the mine site. Concentrations of As, Cd, Cu, Ni, Pb and Zn are enriched in mine water. Acidic mine water samples have low pH (2.5-3.0) and high dissolved solids with electrical conductivity (EC) of about 3800 lS/cm. Low pH in the groundwater (as low as 3.7) was also observed close to the stream draining of the mine. The source of acidity is the oxidation Fe-sulfides (dominantly pyrite) which release Fe, SO 2À 4 and H + forming acid in mine water runoff. Concentrations of Hg are elevated (0.04-1.2 lg/L) in acidic mine water and groundwater exceeding the US Environmental Protection Agency (USEPA) aquatic life Hg standard of 12 ng/L by as much as 100 times.

Journal of Volcanology and Geothermal Research, Aug 1, 2003

The Na^Cl thermal waters of Seferihisar have measured temperatures of 30^153 ‡C, and conductiviti... more The Na^Cl thermal waters of Seferihisar have measured temperatures of 30^153 ‡C, and conductivities of 74005 5200 WS/cm. They issue from Upper Cretaceous to Paleocene Bornova melange rocks, which are made up of sandstone^shale intercalations, conglomerate, mafic submarine volcanics, limestone lenses, serpentinite and limestone bodies, and their complexes, through the intersection of faults. The clay-rich zones of the overlying Neogene terrestrial sediments cap the system. The heat source is the high geothermal gradient caused by graben tectonics of the area. Na and Cl ions mainly dominate the chemistry of thermal waters, thus thermal waters of the Seferihisar area appear to be mixtures of groundwaters and seawater. The seawater contribution in thermal waters varies from 10% to 80%. Assessments from empirical chemical geothermometers, mineral equilibria and silica-mixing model applied on the thermal waters of the Seferihisar geothermal area suggest that the temperatures of the reservoir systems vary between 60 and 180 ‡C. The Seferihisar geothermal area has been physically divided into five main groups and estimated reservoir temperatures provided by the entire methods give the increase as: Dog flanbey Burnu, Karakoc°spa, Dog flanbey, Tuzla and Cumali spa areas in ascending order of reservoir temperature. Hydrogeochemical assessments indicate that thermal waters were mixed with cold waters before and/or after heating at depth in different proportions. The results of mineral equilibrium modeling indicate that the thermal waters of Seferihisar are undersaturated with respect to gypsum and amorphous silica, oversaturated with respect to calcite, dolomite and aragonite, and undersaturated or oversaturated with respect to quartz, chalcedony and anhydrite.

The Germencik geothermal fields that are among the most important fields of Turkey. The fields co... more The Germencik geothermal fields that are among the most important fields of Turkey. The fields contain two geothermal reservoirs. The first reservoir consists of fractured gneiss and quartz schists, and karstic marbles of the Menderes Massif rocks. Overlying Neogene conglomerates comprise the second geothermal reservoir. Neogene aged clastic sediments, especially clayey levels form the cap rock of the system. The heat source may be near surface magma intruded along the active graben fault zones developed by an extensional tectonic regime. The geothermal waters are high enthalpy, meteoric origin and old. Meteoric waters recharge the reservoir rock, are heated at depth, and move up to the surface by convection. Five hot water and seven cold water locations were sampled each month for one year to evaluate the hydrogeochemical evolution of geothermal waters and the hydrodynamics of groundwater systems. All thermal waters in the area are of the sodium-bicarbonate-chloride type and the chemistry does not vary temporarily. The measured temperatures of the thermal springs vary from 50 o C to 70 o C. Estimated reservoir temperatures using various chemical geothermometers and mixing models vary between 150 o C and 250 o C, which correspond with a high enthalpy system. The estimated reservoir temperatures obtained by Na/K and Na-K-Ca geothermometers coincide with the downhole temperatures (200 o C-232 o C) measured directly in nine deep wells. Alteration minerals, which may be formed by the reactions between host rock and thermal fluid, include Ca and Na montmorillonite, Na and K feldspars, zoisite and albite.

Dokuz Eylül Üniversitesi Mühendislik Fakültesi Fen ve Mühendislik Dergisi, 1999

Bu çalışma Türkiye'nin en önemli jeotermal alanlarından birini oluşturan Germencik jeotermal alan... more Bu çalışma Türkiye'nin en önemli jeotermal alanlarından birini oluşturan Germencik jeotermal alanında yapılan hidrojeolojik, hidrojeokimyasal ve izotopik incelemeleri kapsamaktadır. Menderes Masifine ait gnays, kuvars şist gibi çatlaklı kayaçlar ile karstik mermerler jeotermal sistemlerin birinci haznesini, Neojen çakıltaşları ise ikinci haznesini oluşturmaktadır. Neojen yaşlı kırıntılı tortullar, özellikle, killi düzeyleri örtü kaya ve graben tektoniğine bağlı olarak yüzeye yaklaşmış olan mağma ise ısı kaynağını oluşturur. Yapılan hidrojeolojik ve hidrojeokimyasal çalışmalar alandaki jeotermal suların yüksek entalpili, çok az mağmatik katkı içerebilen meteorik kökenli, yaşlı (hemen hemen hiç trityum içermediklerinden en az 50 yıllık) sular olduğunu göstermiştir. İnceleme alanındaki jeotermal suların hidrojeokimyasal evrimlerini ve yeraltısuyu hidrodinamiğini aydınlatmak amacıyla beş sıcak su kaynağı ve yedi soğuk su kaynağı bir yıl süre ile her ay periyodik olarak örneklenerek kimyasal analizleri yapılmıştır. Çalışma alanındaki tüm sıcak sular sodyumlu, bikarbonat klorürlü su tipindedir ve kimyasal bileşimlerinde zamana bağlı belirgin değişimler gözlenmemiştir. Sıcak suların kaynak sıcaklıkları 50 °C-70 °C arasında değişmektedir. Uygulanan çeşitli jeotermometreler ve karışım modelleri alanda 150 °C-250 °C arasında değişen hazne sıcaklığı vermektedir. Alanda hazneye inmiş olan 9 jeotermal kuyuda ölçülen (200°C-232°C) hazne sıcaklıkları Na/K ve Na-K-Ca jeotermometrelerinden elde edilen değerlerle uyuşmaktadır. Aktivite diyagramlarına göre jeotermal suların ilişkide bulundukları kayaç ile tepkime sonucunda oluşabilecek yeni alterasyon ürünleri Ca ve Na montmorillonit, Na ve K feldispat, zoisit ve albit olarak saptanmıştır. This study contains hydrogeological, hydrogeochemical and isotopic investigations in the Germencik geothermal fields which are one of the most important geothermal fields of Turkey. First reservoir of the geothermal system is made up of the fractured gneiss and quartz schists, and karstic marbles of the Menderes Massif rocks. Neogene conglomerates are the second reservoir of the geothermal systems. Neogene aged clastic sediments, especially clayey levels form the cap rock of the system. Heat source may also be the magma closed to the surface along the active graben fault zones developed by extensional tectonic regime. It is understood from the hydrogeological and hydrogeochemical studies that the geothermal waters are high enthalpy, meteoric origin (may also be a little magmatic origin) and old waters (which have hardly any tritium isotopes). Meteoric waters recharge the reservoir rock and are heated at depth and move up to the surface through the tectonic lines by convection currents. Five hot water and seven cold water points were sampled periodically each month during the one year to determine the hydrogeochemical evaluation of geothermal waters and hydrodynamics of groundwaters for the study area. All the thermal water in the area are sodiumbicarbonate-chloride water type and do not reflect apparent variations on their geochemical compositions temporarily. The measured temperatures of the thermal spring vary from 50 °C to 70 °C. It is estimated from the various chemical geothermometry and mixing model applications that the reservoir temperatures of the system vary between 150 °C and 250 °C corresponding high enthalpy system. The estimated reservoir temperatures obtained by Na/K and Na-K-Ca geothermometers coincide with the temperatures measured (200-232 o C) directly in reservoir by 9 deep wells. Alteration minerals which may be formed by the reactions progressed between host rock and thermal fluid were found to be Ca and Na montmorillonite, Na and K feldspar, zoisite and albite on the activity diagrams.

DergiPark (Istanbul University), 2000

Bu çalışma Davutlar-Kuşadası çevresinde yapılan hidrojeolojik ve hidrojeokimyasal incelemeleri iç... more Bu çalışma Davutlar-Kuşadası çevresinde yapılan hidrojeolojik ve hidrojeokimyasal incelemeleri içermektedir. Haritalanan sahanın dışında gözlenen şistler hidrojeolojik açıdan geçirimsiz temel özelliğindedir. Mesozoyik yaşlı Menderes Masifi'ne ait mermerler soğuk sular için karstik akifer özelliğindedir. Bu birimler aynı zamanda yöredeki sıcak suların da hazne kayasını oluşturur. İçerdiği killi düzeyler nedeniyle jeotermal sistemin örtü kayası olan Neojen yaşlı Kuşadası biriminin içindeki çakılltaşı ve ince kireçtaşı düzeyleri ise soğuk sular için akifer özelliğindedir. Neojen yaşlı Kuşadası biriminin killi düzeyleri soğuk su akiferi için geçirimsiz engel kayaları oluşturur. Aktif tektonik hatların ve Pliyosen yaşlı bazaltik volkanitlerin bulunuşu yüksek ısı akısının ve jeotermal gradyanın varlığını göstermektedir. Alüvyon ise gerek beslenme alanının genişliği, gerekse geçirgenliği nedeniyle bol miktarda yeraltı suyu sağlanabilecek iyi bir akiferdir. Ancak son yıllarda artan yazlıkların oluşturduğu betonlaşma nedeniyle, etkin yağışın azalması ve sondajlardan çekilen yeraltı suyunun bilinçsizce kullanılması nedeniyle bu alüvyon akiferde su seviyesi düşüşü ve tuzlanma tehlikesi doğmuştur. Davutlar Kaplıcası suları Na-Cl-HCO 3 su tipinde olup, kalsiti, dolomiti ve silisyumlu mineralleri çökeltici özelliklere sahiptir. Yapılan jeotermometre hesaplamaları ve hidrojeolojik-hidrojeokimyasal değerlendirmeler alanda düşük entalpili (70 o C civarı) akışkan içeren bir hidrotermal karst sisteminin varlığını göstermektedir. This study contains hydrogeological investigations carried out in Davutlar-Kuşadası Region. Schists which are observed at the outside of the mapping area, are impermeable basement rocks known as aquifuj. Overlying marbles are not only karstic aquifer for cold water, but also reservoir for the Davutlar Thermal Water. Conglomerates and lacustrine limestones of the Neogene Kuşadası unit are the aquifer for cold groundwater. The clayey levels of the same unit show an aquiclude characters and are also the cap rock of the geothermal systems of the study area. Pliocene aged basaltic magma may probably be the heat sources. Alluvium is very good aquifer for groundwater deposition and extraction. But these areas and their aquifers have been liable to the danger of the salt water contamination from the sea water intrusion because of the unplanned housing and increasing groundwater usages. Davutlar Thermal Spring waters are of Na-Cl-HCO 3 type, and oversaturated with respect to carbonate and silica minerals. Estimated geothermometry results and hydrogeological and hydrogeochemical assesments showed the hydrothermal karst system which has low enthalpy fluids (about 70 o C).

Taylor & Francis eBooks, Jul 20, 2007

Environmental geology, Nov 20, 2008

Reservoir fluid compositions have been assessed from analytical data on water samples collected f... more Reservoir fluid compositions have been assessed from analytical data on water samples collected from thermal and cold waters in Balçova geothermal field. The results of mineral equilibrium modelling indicate that the waters, with some exceptions, are systematically supersaturated with respect to calcite, aragonite, dolomite, chalcedony and quartz, but undersaturated with respect to amorphous silica, celestite, anhydrite and gypsum and undersaturated or supersaturated with respect to barite, low-albite, K-feldspar, gibbsite and Fe(OH) 3 (a). Calculation of mineral saturation states and geochemical analyses of scale and field observations show that carbonate minerals (calcite, aragonite and dolomite) are most likely to be precipitated as a scale type. Besides carbonates, scale formation risk of amorphous silica, Fe(OH) 3 (a), anhydrite, barite and celestite minerals should be taken into account in some wells and surface equipment. Most of the waters, with some exceptions, have carbonate scaling risk at all temperatures, whereas the other scaling risks only exist over a limited temperature range. While silica, Fe(OH) 3 (a) and barite show a scaling tendency at low temperatures, anhydrite and celestite scaling occurs at higher temperatures.

Turkish Journal of Earth Sciences, 1997

World Academy of Science, Engineering and Technology, International Journal of Geological and Environmental Engineering, 2015

Türkiye jeoloji bülteni, 1999

Çan Jeotermal Alanı, Türkiye’nin kuzeybatısında bulunan Biga Yarımadası’nın orta bölümünde yeralı... more Çan Jeotermal Alanı, Türkiye’nin kuzeybatısında bulunan Biga Yarımadası’nın orta bölümünde yeralır. Çan çevresinde gözlenen baskın kaya tipi volkanitlerden oluşur. Bu kayaçlarda ayrışma zonları ve kil mineralleri oldukça yaygındır. Bunun yanında bölgede gözlenen diğer jeolojik birimler tortul kayaçlar, düşük dereceli metamorfitler ve alüvyondan oluşur. Jeolojik birimler bölgedeki tektonik aktivite nedeniyle yaygın olarak kırık zonları içerir. Termal sular yüzeye bu kırık zonları yoluyla ulaşır. Çalışma alanında gözlenen litolojiler arasında alüvyon en verimli akiferdir. Bu birimdeki sondajların verimleri 5-30 L/s arasındadır. Bu birimin transmissibilitesi ve geçirimlilik katsayısı sırasıyla 50-421 m2/gün ve 1.01-16.8 m/gün arasındadır. Yeraltı suyu derinliği 0.1-8.3 m arasında değişmektedir. IAH (1979)’da verilen su sınıflandırma yöntemine göre termal sular Na-Ca-SO4 tipinde, soğuk sular Ca-Mg-HCO3 tipinde ve kar örnekleri karışık tipte sulardır. Sıcak suların sıcaklık, elektriksel ...

67. Türkiye Jeoloji Kurultayı, 14-18 Nisan 2014, AnkaraBu çalışmanın amacı Çan Havzası’ndaki (hav... more 67. Türkiye Jeoloji Kurultayı, 14-18 Nisan 2014, AnkaraBu çalışmanın amacı Çan Havzası’ndaki (havza alanı 746 km2) soğuk yeraltı sularının hidrojeolojik ve hidrojeokimyasal özelliklerinin belirlenmesini içerir. Bunun için yaklaşık 400 su noktasında (soğuk su kaynakları, sığ ve derin kuyular) hidrojeolojik gözlemler yapılmıştır. Su noktalarının bir bölümünden alınan su örneklerinin kimyasal bileşenleri incelenmiştir. Çalışmalar soğuk su kaynaklarının Çan Havzası’ndaki yüksek kesimlerde yaygın olduğunu göstermiştir. Havzadaki soğuk yeraltı sularının yıllık sıcaklık ortalaması yaklaşık 16°C’dir. Sıcaklık ve elektriksel iletkenlik değerleri yükseklikle ters orantılıdır. Bu çalışmada hazırlanan yeraltı su tablası haritası, havzada genelde yeraltı suyunun Kocaçay’ı beslediğini gösterir

DergiPark (Istanbul University), Dec 1, 2009

Türkiye jeoloji bülteni, 2010

Heat and Mass Transfer, 2022

The tracer test has become one of the most important methods to determine the hydraulic connectio... more The tracer test has become one of the most important methods to determine the hydraulic connection between injection and production wells in a geothermal reservoir. Various chemicals such as fluorescein, radioactive chemicals, salts, and alcohols are used as tracers in geothermal systems. Breakthrough curves of chemical concentrations are matched with analytical models to identify the most representative reservoir model and to obtain important reservoir parameters such as swept pore volume, average fluid velocity, and dispersivity. In this study, we have used sodium fluorescein as a tracer to understand the reservoir characteristics of the Salihli geothermal field in Western Anatolia. The hydraulic connectivity between injection and production wells was identified. The study aimed to determine the most representative reservoir model for Salihli geothermal reservoir. The nonlinear least square method was applied to obtain matches between the analytical models and actual field data. The most representative model was found by evaluating the sum of the square residual. The study includes moment analysis, Dkystra-Parsons, and Lorentz coefficients for reservoir characterization. The study also used flow-capacity and storage-capacity relation to quantify reservoir characteristics for different parts of the reservoir. Fluid velocity in the Salihli geothermal reservoir changes between 2.8 and 19.2 m per hour. Calculated swept pore volume was found between 2 to 13 thousand cubic meter between injection and production wells.