RESOURCE ASSESMENT

of the

SARAYKÖY GEOTERMAL FIELD

at

Denizli Turkey

prepared by

Tahir Öngür

Geologist

on behalf of

DEĞİRMENCİ GROUP of Companies

March 2009

CONTENTS I. INTRODUCTION II. GEOLOGY

II.1. Regional Geology II.2. Geology of the Geothermal Field II.3. Structural Geology II.4. Seismicity

III. THERMAL MANIFESTATIONS III.1. Thermal Springs and Pools III.2. Hydrothermal Alterations III.3. Temperature and Gradient Anomalies

IV. GEOPHYSICS IV.1. Gravity IV.2. Resistivity IV.3. MT IV.4. Sesismic Reflection IV.5. Well Logs

V. WELLS V.1. MTA Wells V.2. MDO-1 Well V.3. İÖİ Well V.4. Umut Thermal Wells V.5. Well Tests

VI. GEOCHEMISTRY VI.1. Hydrogeochemistry VI.2. Gas Chemistry VI.3. Isotoppe Chemistry VI.4. Geothermometers VI.5. Scaling and Hydrocarbon Occurences

VII. GEOTHERMAL SYSTEM(S) VII.1. Regional Framework VII.2. Subsurface Geology VII.3. Thermal and Geophysical Anomalies VII.4. Reservoir Characteristics

VIII. RESOURCE ASSESMENT IX. RESULTS X. PROPOSED DEVELOPMENT STUDIES

I. INTRODUCTION A resource assesment study was done for a geothermal field at Denizli province, iner West Anatolia. This research area is registrered to MTA General Directorate. Beside this, there are 7 well and 6 natural geothermal discharge license in this area. Değirmenci Group has a well license at eastern part of area; while, Umut Thermal company have 5 well and 6 natural geothermal spring and pool license. Another single well license owned by Denizli Prpovincial Administration at central part of the area. Now some negotiations are being continued between related parties to make collective efforts for developing this geothermal area. This area is situated just south of the Kızıldere Geothermal Field. There are plenty of geothermal manifestations at South of Menderes River and is unique for this side of the Büyük Menderes Graben. Boundaries of this license and existing geothermal wells are shown at image below.

Figure.1: Assessed License Area and Existing Geothermal Wells

Değirmenci Group takes an active role in development efforts and requested an assesment study fort his area. This assesment was done to evaluate the geothermal potential of this area and to make some quantitative predictions. This study has realized by a multidisciplinary expert team consists of Dr Umran SERPEN, Dr Niyazi AKSOY and Tahir ÖNGÜR. Owing to the existence of several hot weater springs, exploration holes, productive wells and proximity to the well developed Kızıldere Field, there abundant data and published or unpublished studies related with this area. This area was named as “Sarayköy Geothermal Field” to differentiate here from either Kızıldere or Tekke Hamam areas.

All of available information as papers, articles, abstracts, unpublished reports, maps and sections, analysis, data, etc. were reworked and evaluated to do this assesment. Whole of these evaluated and interpreted at this text. The largest (in size and output) regional heat flow anomaly in Turkey is found at the Menderes Metamorphic Massif (MMM). Several recent grabens have developed within the MMM, where all the geothermal fields are of medium-to-high enthalpy, with temperatures in the 120–240°C range. The thermal fluids are of alkaline-bicarbonate compositions, have high-CO2 contents, and show evidence of water–rock interactions and mixing with shallow waters. The geothermal reservoirs are generally hosted in different units of the metamorphic basement, which typically presents gneissic thrust sheets. In the grabens, some shallow reservoirs are found in the Miocene sedimentary sequence covering the basement rocks. The accumulation of these sediments in Miocene-Lower Pliocene grabens, bound by NE–SW and NW–SE striking normal faults that are oblique to today’s structures, is typical of the MMM area where the geothermal systems are located. Other widely shared characteristics are the very large total vertical displacement of either the Miocene or Recent graben structures through a set of stepped faults, the existence of antithetic faults in the grabens, and the occurrence of horst-graben sets. In summary, the geologic structure of the MMM geothermal fields is quite complex. In Western Anatolia there are about ten E–W trending grabens that are 100–150 km long and 5–15 km wide. Thick sedimentary columns were deposited in continental basins bounded by N–S faults resulting from Mid-Miocene to Lower Pliocene E–W extensional tectonics. The extension slowed down for a short period at the end of Lower Pliocene and the region was denuded. The present graben systems began to form when the direction of the extension changed to N–S and speeded up again. The E–W faults of the new grabens truncated the previous NW–SE graben faults underlying them. Either the Miocene or post-Pliocene E–W grabens and the interrelated very low-angle gravity detachment faults developed as a result of the uplift of the MMM. Present-day seismic activity over the graben faults and detachment environments show that the stresses in these zones are stil high. The recent thermal history of the MMM has not been sufficiently investigated. During the uplift of the Massif, the rocks that had previously reached thermal equilibrium were rapidly raised and were not able to cool at equal rates. It is estimated that the continental crust can only attain its thermal equilibration in about 100 million years and accordingly the MMM could not have had enough time to cool. There has not been any recent volcanic activity in the MMM and the youngest magmatic intrusion is about 19,5 Ma old. The ages of migmatitic products accompanying some detachment zones are younger and change along the strike. The Germencik, Aydın, Salavatlı-Sultanhisar, Kızıldere and Denizli geothermal fields in the Büyük Menderes Graben, the Salihli-Kurşunlu, Caferbeyli and Sart, Turgutlu-Urganlı and Alaşehir-Kavaklıdere geothermal systems in the Gediz Graben, the Dikili-Kaynarca and Bergama geothermal systems in the Dikili-Bergama Graben, and the Simav geothermal field in the Simav Graben are all located within the same geological framework. Most of these geothermal resources are located asymmetrically in these faulted zones, especially in the areas where the faults obliquely intersect the Miocene grabens; i.e. on only one flank of the grabens (at the northern side of southern Büyük Menderes Graben and at the southern side of the northern Gediz Graben). In summary, the rapid uplift and high-erosion rate of the region’s complex upper crust created an abnormally high-heat flow. The intense fracturing of the metamorphic rocks provided substantial permeability that helped the development of geothermal systems in some zones (Serpen, et.al., 2009). It obvious that Sarayköy Geothermal Field is situated at a very interesting zone and looks very promising.

II. GEOLOGY II.1. Regional Geology Some geological problems and discrete interpretations on geological environment and geothermal fields of Menderes Massive and Büyük Menderes Graben must be discussed to recognize the Sarayköy Geothermal Area. These questions (or problems) can be listed as below :

Is the geological past of Menderes Metamorphic Massive known sufficiently by its deposition, metamorphism, structural complexing aspects and emplacement processes to actual position? Is there a concensus on these aspects?

How was the evolution of graben tectonics during Upper Tertiary which was also controlled the Tertiary sedimentations? How the stress directions and geometrical configurations of resulting depositional lows and rising structures have been evolved?

Is the vertical displacement of Menderes Metamorphic Massive was finished or is proceeding?

Is the recent thermal history of Menderes Metamorphic Massive is known enough? Can some volcanic activities and/or their evolutions around the Menderes Massive

be the cause of regional high heat flow, or contributing to this? Is the interpretation of some researchers as the “Büyük Menderes Graben is a “rift”

structure” true and how this kind of a model can influence geothermal systems? How information gathered by exploration activities at these geothermal systems

themselves contribute some answers to above mentioned questions? These aspects will be examined below and a reliable geological knowledge base will be gathered to understand the Sarayköy Geothermal Field.

Is the geological past of Menderes Metamorphic Massive known sufficiently by its deposition, metamorphism and structural complexing aspects and emplacement

processes to actual position? Well enough!

Is there a concensus on these aspects?

No! Formerly, this Metamorphic Basement, rock units of Menderes Massive have been called as Paleozoic aged at several publications. Beside this, metamorphism has been explained as if it took place in single phase and mostly at the end of Eocene. Another general acceptance is the Massive had upraised at the end of this metamorphism and as a result of this, some E-W extending faults have formed actual grabens. But, metamorphosed rock units are very similar with Paleozoic-Upper Mezozoic units of Taurids and/or Pontides. Massive can’t be explained only by Paleozoic units. Some metamorphosed rock units must be Mesozoic aged. Nevertheless, as the research studies on Menderes Massive were deepened, have changed and became widespread during last thirty years period. Eventually, a rich knowledge base has been developed on the Massive’s complex structure. Menderes Massive Metamorphics are divided into two main subunits generally: “Core” and

“Cover”. Core consists of highly metamorphosed schists, leptite gneisses, eyed gneisses, metagranites, migmaties and metagabros. On the other side, Core consists of micaschists, fillites, metaquartzites, metabasit, metaleucogranite, kloritoide-kyanite schists, metacarbonate and metaolistosthroms. Stratigraphical sequence and metamorphic history of Menderes Metamorphic Massive (MMM) were compiled in detail and published by Özcan Dora and his colleagues. Dora(1995) summarizing these as at long quotation below: “Evaluation of geological information and structural evolution of MMM can be done under the light of multiphase metamorphism model, as below: I) Sedimentation of the source rocks of leptitgneiss and core schists, first metamorphism (M1) and emplacements of basic and plutons. Oldest rocks of MMM, mudstones, tuffite and shales which were source rocks of leptite gneisses and core schists which were dated to between 585-1870 million years according to zircon detritus had been deposited onto a yet unknown older Precambrian aged acidic craton. Those units had been metamorphosed (M1) in upper amphybolite-granulitic facies under the circumstances of Pan African continent to continent collision during Precambrian-Cambrian boundary. Synchronous or following metamorphosed granitoides accompanied to this 550 million year before. II) Deposition of Paleozoic units of Cover, Variscan Metamorphism (M2) and emplacement of Triassic aged leucogranits. Paleozoic units consists of quartz arenites, metaconglomerates with granite gravels derived from Pan African Basement and limestone, shale and quartz arenite alternations from bottom to top as deposited over the eroded Pan African Basement during Ordovician-Permocarboniferous era. This sequence has been metamorphosed during the “Variscan Orogen” together with core units (M2) and leucogranites have been emplaced in it during Lower and Middle Triassic. Their ages have been determined as between 240-230 million years. III) Deposition of Mesozoic-Tertiary(?) units as Cover series and double “Tertiary Metamorphism” (M3, M4). Existence of some conglomerates at bottom of platform type carbonates shows that there is a discordance between Paleozoic and Mesozoi sequences. Upper envelope of the Cover sequence consists of an olistostromal unit which covers platform carbonates with boxite deposits and ophyolithic and carbonate blocks deposited during Upper Triassic-Paleocene(?) from bottom to top. Either core or cover units of Menderes Massive have been metamorphosed by a Tertiary two fold process which is related with the closing of Aegean Neotethys Ocean and under thrusting of the Anatolian-Taurid Platform through to north, under the İzmir-Ankara Zone,as similar with Cyclad Complex. High Pressure Metamorphism (M3) has evolved under circumstances from epidote-blue schist to eclogite and then Barrowian type “Main Menderes Metamorphism” (MMM) (M4) has been developed during Upper Eocene. compressive stress environment at the end of this final medium pressure metamorphism brings inner folding and overthrusting of core units over the upper levels of cover sequence. IV) Extensional tectonics, synchronous granite emplacements, development of detachment faults, uprising and Depletion of the Menderes Massive. Extensional tectonics environment which was developed at Western Anatolia during Lower Miocene caused the rising and depletion of Menderes Massive and development of huge detachment faults and fragmentation zones have accompanied to this. 19,5 million aged synchronous granites have been emplaced into the Cover series and made contact metamorphism in bedrock. Huge detachment faults and up to 100 m’s thick fragmentation zones have been developed in brittle zones during the uprising and depletion of central massive (Kiraz-Ödemiş Sub Massive). Following these processes graben forming gravity faults were developed under true brittle conditions through E-W directions and cut either these fragmentation zones in Basement or Neogen deposits covering this. Neogene deposits at Gediz Graben have been emplaced tectonically over this fragmentation zone as as lean back to south with 15° through these gravity faults. Geothermal systems at mid of Massive and several Middle to Upper Miocene medium composition to basic volcanic extrusions are related directly with this graben system.” It can’t be said that everybody agrees with these explanations. For example, there are some researchers who advocate that the metamorphism has developed in only single phase. According to them, metamorphism of the Basement has developed during Eocene under the medium to high temperature facies (Erdoğan, 1992; Satır ve Friedrischen,1986; Hetzel and Reischman,1996). This type of orogenic belts at where some crustal shortening has occurred in different locations of the world were investigated in detail.

How was the evolution of graben tectonics during Upper Tertiary which was also controlled the Tertiary sedimentations? How the stress directions and geometrical

configurations of resulting depositional lows and rising structures have been evolved? First important tectonic movement that occurred at the region is the emplacement of tectonic associations over and over as nappes. Then, NNE-SSW direction overthrustings plunged to west and large scale closed and easterly overthrown isoclinals folds were developed under the NW-SE directed compression stresses. After this compressional phase tensional stresses have been dominant and gravity faults with WNW-ESE and NE-SW directions have formed. These large displacement faults were developed after the Akitanian. Finally, tension forces emerged from the domal uplift of Menderes Massive started by Pliocene results gravity faults which are shaping large grabens. General structural evolution of the region can also be summarized as below according to Yılmaz et.al., (2000) : ‘‘New map data was collected with recent studies conducted at Western Anatolia to finalize the discussions on the timing and general formation mechanism of Western Anatolian graben system, and it was determined that N-

S directed grabens had been formed under the E-W stresses at Lower Miocene during the first phase. Some openings developed under the influence of tensional stresses accompanying N-S oblique shear faults make easy the rise of calcalkaline, hybride composition magmas to surface. A N-S tension stress environment has been prevailing during Upper Miocene. A main breakup fault has formed during this period. A part of lower plate has been arised over the upper plate levels and outcropped at Bozdağ Horst and longitudinal grabens through E-S direction have been formed. Alkali Basalt lavas erupted from these fault systems. N-S elongation has been terminated at the end of Upper Miocene or Lower Pliocene as already shown by a regional horizontal erosional surface which was developed at Neogene units which covers also Upper Miocene-Pliocene sequence. This erosional surface

Figure.2 : NNE-SSW Extending Graben Structures at Menderes Massive erased nearly whole topographical irregularities, including Bozdağ Rise. Then, this erosional surface disrupted by revitalized N-S tensional forces and the structures which controlled the formation of Lower to Upper Miocene sequence, have been cut by roughly E-W oriented gravity faults. This provided that the formation of actual E-W extended grabens at Plioquaternary.” Tectonic evolution of Menderes Massive systematically being discussed at Yılmaz(2002) as had been done at Yılmaz(2000). There about ten E-W trending graben structures at Western Anatolia with about 100-150 km lengths and 5-15 km widths. Büyük Menderes Graben is one of these (Fig.2). Investigations show that thick volcanosedimentary units have been deposited during Lower to Middle Miocene in these continental basins which are limited with N-S gravity faults developed under the E-W tensional forces. Whole Western Anatolia has been covered by interrelated lakes. Magmatic and volcanic rocks of this period are high potassic, calkalkaline and hybride compositions. N-S extension had been started during Upper

Miocene. Detachment Faults at Bozdağ at center have started to formation and Bozdağ has emplaced. Redish colored coarse clastics have been deposited around the Bozdağ while light colored lacustrine limestones at far away. Alkali basaltic lavas extruded during Upper Miocene-Lowe Pliocene in pulsed manner. N-S extension has been slowed for a short period at final stages of Lower Pliocene and a regional erosional surface had been developed. Actual graben systems have started when N-S extension restarted again.

Figure.3 : Evolution Phases of Graben Systems at Menderes Massive (after Yılmaz, et.al. 2000)

Graben forming E-W faults interrupted the continuity of old N-S grabens and suspended them (Figure.3). Okay(2002) has discussed also the timing, start and reasons of this process. Okay investigated the Kazdağ Massive at NW Anatolia. Metamorphic core is outcropping at mid of this massive. Bedrock consists of marble and gneiss which were metamorphosed under 5±1 kbar pressure and 640±50ºC temperatures. Average muscovite and biotite Rb/Sr ages are 19 My and 22 My and points to a metamorphism took place at Oligocene under high temperatures. Cover units consist of a mélange which was deposited in a Cretaceous aged ocean and includes some unmetamorphosed Cenonian eclogitic lenses. Cover and core units separated by a brittle shear zone which consists of two kilometer thick gneiss protoliths Highly metamorphosed rocks show northerly directed and northerly plunged mineral Figure.4 : Structural Evolution of Menderes Massive

lineations. This shear zone was cut by an undeformed granitoid, which was aged as 21 My by Rb/Sr method as similar with ages of accretioanry mélange and highly metamorphosed core rocks. Estimated pressure for metamorphism and granitic emplacement shows that metamorphic rocks had arisen quickly from 14 km depths to about 7 km’s along shear zone about 24 My ago. Metamorphic rocks of Kazdağ surrounded by huge amounts of calkalkaline Upper Oligocene-Lower Miocene aged volcanic and plutonic rocks which were developed on the northerly dipping Helenic subduction zone. All of these show that the Upper Oligocene regional spreading doesn’t related with gravitative collapse; but, directly with rolling back on this subduction zone. A similar process has been experienced also at Menderes Massive. According to the information given at Dora et.al.(1995) eclogites encountered at around Birgi and Tire territories had reached up to 13 kb pressure and 650°C temperatures as an evidence to their maximum burial depth of at least 40 km. This could be only by crustal thickening tectonically, folding onto itself. This part of crust obviously rised about 40 km since then, and depleted by several ways. Yılmaz et.al.(2000) conclude that crustal thickening since Upper Cretaceous at between Thracia and northern Mediterranean as a result of collision of Taurid and Pontide continental plate fragments through İzmir-Ankara Suture Zone, isn’t small than 200 km’s and has been run through to Upper Eocene-Oligocen at north, while through to Upper Miocene at south. Continental crust represented by Menderes Massive has been shortened about 200 km’s during this time period and after this, raised about 40 km’s since then. Most part of the Massive was depleted during this rise. Some other views contrary or complementary to above given general evaluation are already being published. Detachment faults concept is an example for this. Recent detailed structural geological investigations which were done at different metamorphic massive around the world revealed that a thick slab of top layers of the rock column have lost their stability, detached from underlying mass, displaced and these shear systems are being called as “detachment zone”. Those zones look important for geothermal investigations owing to their intensely fractured, thick fragmentation zones. Most studied and correlated massive with this kind of structures are “Menderes Massive” at Turkey and “Basins and Range” at US. There are typical metamorphic core complexes, spreading faults, turtle back faults, shear zones, detachment surfaces and extensional sedimentary basins synchronous with this extension at these two regions according to Çemen(2002). Seyitoğlu(2002) analyze different examples of these structures from Western Anatolia. These vertical rotational tectonic processes can be understood more by magnetostratigraphical data and Alaşehir and Büyük Menderes grabens were investigated by this manner by Şen(2002). Author has dated older ones of four depositional cycles as 14,6-16,7 and 16,73-18,28 My matching to Lower Miocene. Paleomagnetical deviation has found as 25º counterclockwise at Alaşehir Graben and 30-40º clockwise at Büyük Menderes Graben and this difference has been attributed to detachment faults. It was conluded that this type of inverse vertical axis deviations at Western Anatolia isn’t related with solid crust movements, but, related with deformation of a thin skin over crust. Catlos (2002) made Th-Pb ionic microprobe measurements at growing haloos at granates of Menderes Massive Metamorphites and conclude that detachment zones effectively depleted rock uinits at depths of crust since Pliocene. Thus, core of the crystalline massive that is heaving and rising at very large fields destabilizes and slides over the cover units through nearly horizontal, maximum 20° dipping large faults. Some research results were published

related with the existence of this kind of structures at Menderes Massive. For example, Emre and Sözbilir(1995) affirm that there are two large detachment faults at metamorphic rock mass at south of Gediz Graben and northern side of Büyük Menderes Graben; fault observed northern part of Büyük Menderes Graben is older (at the start of Miocene) and southern side Gediz Graben fault is younger (later Miocene); Bozdağ core complex is staying assymtrical; Miocene and Pliocene sediments have deposited in throughs of structures as dominos at north and as quasi graben-tilted block type; these faults are active and some seismic activities are being recorded yet. Bozköy Overthrust as previously described in Menderes Massive is a detachment fault and Büyük Menderes and Gediz Graben’s aren’t typical grabens and latest products of these detachment movements. This coercive modeling looks weaker either than Yılmaz et.al.(2000)’s explanation of whole Western Anatolian grabens together, or than Candan et.al.(1992)’s translation model of metamorphytes, or young sediment depositions at other sides of Büyük Menderes and Gediz Grabens. But, the fragmentation of thick metamorphic rock horizons along either Bozköy Overthrust or detachment faults is obvious and this has provided suitable environments for the circulation of geothermal fluids. This evolution proceeds staggered and different ages and characteristics of sedimentary deposits at each stage are suitable for prediction of some unobservable aspects at the field.

Is the vertical displacement of Menderes Metamorphic Massive was finished or is proceeding?

According to the above given quotations and explanations the rising of the Menderes Metamorphic Massive has started just after its final metamorphism at the end of Eocene. This rise and depletion process has developed mostly at Bozdağ Rise, at north of Aydın. Whether old grabens shaped by NW-SE/NE-SW at inner parts of Massive and N-S at outside of it, which have controlled the Miocene deposition or actual grabens shaped by post Pliocene E-W faults have been obviously developed under the influence of tensional stresses which were arisen at outer periphery of the Massive as result of its domal rising. Apparently, heaving, formation of old and actual grabens run up to date. Now, continuing earthquake activities along graben faults is most direct proof of the continuing stresses over these fault mechanism.

www.e-harita.com.tr

www.sayisalgrafik.com.tr

Ahmetli

Bek

Beydağ

Güney

Kiraz

Nazilli

Sultanhisar

Söke

Ulubey

Uşak

Çal

Çine

Kula

Figure.5 : Seismicity of Menderes Massive between G. Menderes and Gediz Grabens (sayisalgrafik.com.tr) Besides, Emre and Sözbilir(1995) quoted from Eyidoğan and Jackson(1985) that there are

fault surface analysis for some events that these taking place on horizontal or very low angle detachment faults. But, most obvious proofs of this continuing activity can be detected from geomorphological characteristics of region. As already known that the grabens at two sides of Bozdağ Rise is assymmetrical. Southern side of Gediz Graben is is steeper, such as northern side of Büyük Menderes Graben. Menderes River continuously displaced to southern side of Graben. Alluvial plain between river and northern margin isn’t horizontal, sloping to south. There are alluvial fans at mouths of all valleys at northern side o Graben and these are proceeding. Northern side faults look young or active with steep slopes and triangular faces. Strictly speaking, the uprising of Menderes Massive and resulting stresses are going on. But there isn’t any data about the rate of this.

Is the recent thermal history of Menderes Metamorphic Massive is known enough? There isn’t a detailed evaluation study on this subject. But, this question must be answered: “Are the rising velocity of Menderes Massive is higher than cooling velocity?” Can rock masses which were in thermal stability appropriate to related depths of crust and raised quickly to shallower depths be cooled with a rate accordant to the rising of Menderes Massive? A rock mass situated for instance at 4000 km depth 1 million years ago couldn’t find sufficient time to cool from 147°C temperature to 81°C temperature which is appropriate for 2000 m depths at normal heat flow conditions with a rising speed of 2 mm/year. It is certain that thermal stability at Menderes Massive which is already known with its rising about 40 km in 35 million years, might be deteriorated and recovered time by time owing to increasing and decreasing rising rates. This can be understood more clearly under the light of the prediction as that continental crust can obtain its thermal stability only in 108 years which was proposed at Sclater vö(1981) and quoted at Güleç(1988). Then, Menderes Massive couldn’t have sufficient time to obtain its thermal stability.

Can some volcanic activities and/or their evolutions around the Menderes Massive be the cause of regional high heat flow, or contributing to this?

There isn’t any true young and recent volcanic activity at Menderes Massive. Most typical one is the old volcanism at N-S grabens and its surroundings at NE’ern edge of Massive. It is impossible to explain actual high heat flow with this old volcanism, even their near surroundings. Anyhow, there aren’t any old or recent volcanic products at inner parts of Massive, for example, around Büyük Menderes Graben. Kula Volcanites are products of deep tension cracks developed at rigid continental crust in low temperatures and situated at far away from Büyük Menderes and Gediz Grabens. Dora et.al.(1995) refered to Hetzel et.al.(1995) that the age of youngest magmatic intrusion was measured as 19,5 million years. Concludingly, unusually high heat flow exposed by geothermal systems at Büyük Menderes Graben can’t be explained by volcanic and magmatic activities.

Is the interpretation of some researchers as the “Büyük Menderes Graben is a “rift” structure” true and how this kind of a model can influence geothermal systems?

“Büyük Menderes Rift Zone” term are being encountered at some publications which are discussing the general characteristics of geothermal systems encountered at Büyük Menderes Graben. For instance, Özgür(2003) use this term as, “Tectonic situation of the Eastern Mediterranean between Eurasian and African Plates are being controlled by Anatolian and Aegean Subplates. Plate tectonic evolution, results the rising of Menderes Massive under compressional stresses from Oligocene to Lower-Middle Miocene.

E-W’erly directed Büyük Menderes, Gediz and Küçük Menderes rift zones have developed as products of extensional tectonics from Lower Miocene to Middle Miocene. One of these is the Büyük Menderes Rift Zone which is extending from Denizli at east to Kuşadası at Aegean coast and hosts several geothermal resources such as Kızıldere, Salavatlı and Germencik at Menderes Massive. It is related with Middle Miocene to recent volcanism. These geothermal waters are related with NW-SE and NE-SW faults which were developed with rising between two extensional rift zones and compression stresses and which are extending oblique to the Büyük Menderes Rift Zone. There is a very intensive volcanic activity from calkalkaline to acidic at various locations the ages of which vary from Middle Miocene to 18.000 years before present beside heat flow anomalies at Büyük Menderes rift zone. According to the δ87Sr/δ86Sr and δ144Nd/δ143Nd isotopic analysis results these volcanic rocks have been emerged from continental crust and can be considered as heat source for thermal waters at Büyük Menderes Rift Zone and other places. Moreover, geothermal gradients can add heat to thermal reservoirs at limestone, marble, quartzite and gneisses.” Author, didn’t discussed the rift concept at his paper and didn’t exhibit any data related with this propositions. There isn’t any old or young volcanism in or around this graben as has been explained above. Examples given by Özgür(2003) is 15,0-16,7 My old Middle Miocene volcanic products at Küçük Menderes Valley; and others are Upper Pliocene aged volcanites at Denizli and Söke and 7,5 My to 18 Ky old Kula volcanites which has been noted by Özgür as far as 150 km. All of these are encountered at outside of grabens, far from geothermal activities and differing volcanic products which were developed under different petrogenetic conditions and at different phases. It can’t be acceptable to say that these graben systems are rift, geothermal heater is volcanic activity by considering these. Also, views on that isotopic chemistry of hot waters show the water rock interactions, that 14C isotopic composition can be explained by reaction of hot waters and deep carbonate rocks for origine of CO2 that the minor quantities of heavy metals at waters and that F and B’s behavior parallel to Na as a sign of the origin of water as interaction with metamorphic rocks, can be used for explaining another models. But, author concludes that the recharged waters infiltrate down to 4000 m depths to top of a magma stock and heated. There is a unique proof to this rationalization; mantle origin of the 3He in water. But the author of referred paper close the door to explain Menderes Grabens as rift by only this data, “Most of the 3He loss from mantle are being occurred at oceanic basins as related with the formation of oceanic lithosphere and its cooling. Nonetheless, minor amount of 3He is being lost through continental crust when this is under the influence of actual deformations. Transfer mechanism of Helium from mantle to crust can’t be understood appropriately yet …” Güleç mentioned several probabilities for richness of helium such as richness of mantle origin helium at where the actual continental crust is being under the influence of extensional tectonics may be related with mantle fluids, or, mantle origin helium occurred at extensively at Western Anatolia and thus can’t be correlated with local plutonic activities, but the existence of mantle fluids at bottom of the crust; or, mantle origin helium could be trapped in continental crust where the thermal stability could be gained again in very long period as could be pointed out by Sclater et.al.(1981). Obviously, richness of mantle origin helium at geothermal waters of this region isn’t a simple and reliable indicator for Özgür(2003)’s rift hypothesis. In short, geological history of Menderes Massive’s itself provides required and sufficient explanation on the excess amount of mantle origin helium at Western Anatolia. But, it must be reminded of that Özgür(2003) points out that high temperature gradients can warm up the deeply circulated waters at this region is also probable. Another important study is the estimation of young sediment thickness in Aegean Grabens by 2D and 3D modeling of regional gravity data. Results show that there are more than 1.500 m thick deposits at grabens, up to 2500 m at Büyük Menderes Graben. Another interesting aspect is that variations of these thicknesses along grabens and increase of these thicknesses where the actual grabens are being wider. It is clear that the equal thickness contours are deviating from E-W and turns to NW-SE at these widening zones. For example, there is an inner basin at the east of Aydın and its sedimentary deposition thickness exceed 1500 m’s. Rift term which has been used by Vengosh et.al.(2002) and has been criticized by Serpen and

Öngür(2002) similarly.

Figure.6 : Distribution of Thickness of the Young Sediments at Grand Menderes and Gediz Grabens

(after Sarı and Şalk, 1995) Where a typical rift can develop, and what are characteristics of it? Rising of earths crust under the influence of uprising branches of convection cells in mantle and stresses emerged from their lateral movement to two sides breaks the continental crust to rifts and dislocate it to two sides. The crust doesn’t be thicker here, is being thinner at rift zones. Splitting occur at just the maximum rising and crustal thinning axis. 12 rift type crustal splitting can’t be formed as small as Western Anatolia. Only a single splitting can be developed at a broad crustal region at rift zones. Because, dimensions of the mantle convection cells are very large according to the thin crust and none of minor convection cells can develop in mantle. New mantle material, mantle origin magmatics and some basaltic plate dykes are being emplaced in to the widening splitting zones. None of young sediments can be deposited here. Besides, these compositions of the volcanic material at these zones can’t be calcalkaline or hybrid such as Miocene or younger volcanic occurred at Western Anatolia; oceanic basalts are typical for these zones. Furthermore, temperatures of these magmatic materials are very low according to the magmas developed at continental crust. It looks very difficult to call the graben systems of Menderes Metamorphic Massive as rift.

How information gathered by exploration activities at these geothermal systems themselves contribute some answers to above mentioned questions?

Geothermal resource investigations have been done at most of the geothermal fields from Pamukkale/Karahayıt at east and Germencik at west and a rich knowledge base was collected. This information looks capable to shed light onto the crustal structure of this region and characteristics of Menderes Massive and Graben. When summarized, thermal waters are meteoric origin and their mineral composition have been gained by water-rock interaction. Rich CO2 gas content had been generated by reaction of hot waters and carbonate rocks at depths. There isn’t any need to assume the existence of young or recent magmatic or volcanic

activities at depths where no surface manifestations exist. Hot waters are rising through actual EW graben faults. There is an unusually high heat flow at this region and deeply circulated waters can easily be heated. Uprising zones of geothermal systems located preferentially at intersections of actual E-W graben faults with older and oblique NW-SE/NE-SW extending Miocene graben faults. Well-drilling operations have proved the existence of Miocene depressions at Büyük Menderes Graben and their being widespread. There is an important lateral thrusting structure at Metamorphyc Basement (Bozköy Overthrust) and this was formed by detachment faults after destabilization of uprising Massive. These kind of detachments are typical especially at around Aydın, between Salavatlı-İmamköy-Germencik. On the other hand, some hydrothermal alterations have been developed by hot water-rock interactions and some new mineral paragenesis appropriate to current P-T conditions have been formed at these zones. Most detailed study on these hydrothermal alterations was done by Karamanderesi(1997) and published at Tübitak Earthscience Bulletin. This study can lead some conclusions also for Aydın Geothermal Field with its similar characteristics. This study concludes that mercury and antimony mineralization and rutil mineralization at quartz veins have been formed at first phase. Gabbroic and realted dykes have been emplaced at second phase. Gneiss was alterated hydrothermally, then. The third phase distinctive with granitic intrusions and some specularite, talc, calcite, quartz and aragonite mineralizations was formed at peripheral zones of these intrusions and travertines were deposited. Forth phase was occurred during the N-S faulting and hydrothermal albite and chlorite mineralization were typical. The final phase is typical for active fault zones where the hot waters are circulated. Some new minerals such as kaolinite, illite, montmorillonite, dickite, vermiculite, calcite, pyrite, dolomite and hidrobiotite have been formed at Upper Miocene deposits. These were assumed as represent 150-300°C temperature range. Albitization and chloritization are typical at Metamorphic rocks. Authors explained the existence of vermiculites at bottom of gneisses with existence of a closer magmatic intrusion and didn’t tried to discuss the probability of an old process while the gneiss originally furnished by different aged intrusions. Concludingly, geothermal resource investigations provided important information concordant with regional geological models and proving these. This information can be considered as a guide for future geothermal investigations at other fields. II.2. Geology of Denizli Basin Investigated area is located at the SW’ern corner of the MMM. This location forms the juncture between Çürüksu, Gediz and Büyük Menderes Grabens. Beside this, Tertiary sedimentary basin is widest here in whole of the Aegean Region. Şimşek(1985a) summarized the geology at and around Denizli Basin as, “The basement rocks in the vast areas of West Anatolia are Menderes metamorphics of the Paleozoic or older period. At the base of the metamorphics are augen gneisses.These are typically exposed within the massif in the deeply eroded horsts of Buldan and Yenice. These gneisses are classified as augen, biotite-bearing and lustre gneiss, according to their texture and mineral composition, but are classified as ortho and para according to their origin. The upper parts of the gneiss appear to alternate with quartzites and schists in some places, reaching thicknesses of 150 m in parts. Generally, this unit is overlain by a rather thick unit of schists, known as the micaschist unit, and bearing considerable amounts of garnet, muscovite and biotite. İğdecik Formation forms the uppermost unit of the metamorphics in the study area. It is composed of marble, calcschist, quartzite and schist alternations, and has been studied in detail in correspondence to the Buldan horst and named after it. The rocks of this unit are commonly fractured and faulted. Lower Pliocene units are the earliest continental - lacustrine deposits that cover the massif. A large stratigraphic gap exists between these rocks and the basement units. Kızılburun Formation rests on the metamorphics with a basal conglomerate. Upwards it consists of an alternating succession of variegated, red to brown conglomerate, sandstone, mudstone and claystone, intercalated with lignite beds in some parts.

Kolankaya Formation appears as alternation of yellowish and light brown sandstone, claystone and clayey limestone. There are distinct marker beds composed of limestones within this. Their thickness reaches to 500 m. The Plio- Quaternary Tosunlar Formation overlies the Lower Pliocene and Paleozoic units with an angular unconformity. It consists of alternations of a grey, poorly consolidated, partly bouldery conglomerate, sandstone and mudstone with fossiliferous clayey limestone. Thickness is about 500 m. The Quaternary is characterized by terrace deposits, alluvium, slope debris, alluvial fans and travertine.” Taner(1974a-b and 1975) has studied the eastern part of Denizli Basin Neogene deposites and concludes that whole of the sequence consists of Pliocene sediments. She proposed a strathygraphical column for Denizli Basin as given Fig.7. On other side, Kaymakçı (2006) concludes that “Age of the basin-filling units of the Denizli Basin are dated by the mammal fauna and range from Early–Middle Miocene to Recent. Early to Middle Miocene units are widespread, while Late Miocene to Recent units are restricted to the Denizli Basin. This is relationship is interpreted to indicate that the deposition of the Early to Middle Miocene units predated the development of the Denizli Basin.” Westeway (1993) gave a detailed geochronology for the Denizli Basin, too. Figure.7: Stratigraphycal Column Proposed by Taner(1974) for Denizli Neogene

Figure.8: Stratigraphy of Denizli Neogene (after Westeway, 1998)

Cover series of the MMM at southern flank of the Denizli Basin, Babadağ Caledonian Massif consists of Carboniferous-Permian limestone, sandstone and schists(Yalçınlar, 1964). Okay(1989) considers these as Likian Nappes. II.3. Geology of the Sarayköy Geothermal Field Uysallı(1967) was the first geologist, who had prepared a geological map for a part of the Sarayköy Geothermal Field. He concluded that Miocen sediments stays over the Metamorphic Basement with an angular disconformity and this limestone sequence is Lower Miocene aged. Conglomerate, sandstone and sandy and marly Lower Pliocene sedimentary sequence transgressively covers this Lower Miocene with an angular discordance. This 200 m thick sequence has deposited at lymnic, fluviatile environment. A copy of Uysallı’s gepological map is given at Fig.9. Erişen divides the Denizli Neogen as Lower and Upper Pliocene which is separated by an angular discordance. But author said that “There is only Lower Pliocene units at this area according to the paleontological data and Upper Miocene looking units is being aged as Lower Miocene” (Taner, 1974a). Öngür(1971) points to existence of a Miocene sequence with marls of “Ahıllı Marl Member” at South of Babadağ Town (Oğuzlar-Kıranyer-Ahıllı villages) and limestones of “Hisar Limestone Member” at western part of the area. This Miocene starts with marin sediments

and transforms to a brackish lake and at the end of Pliocene environment turned to fresh water environment. Author recognized the existence of Pliocene sediments and the reprensented by sand-clay, limestone and conglomeratic limestones (Taner, 1974a).

Figure.9: Geological Map of the Tekke Hamam Region (after Uysallı, 1967; Red line is the boundary of SGF) Özgüner, et.al.(1975) presented a partial geological map covering the western zone of the site.

Figure.10: Geological Map of Tekkehamam Region (after Özgüner et.al., 1975)

Karamanderesi and Ölçenoğlu(2005) described the section as, “At the bottom; biotite, muscovite, epidote, chloritoid, quartz schist of Menderes Massif metamorphics (between 2401-2040m). Above this strata, marble can be seen as the main reservoir (between 2050-1950 m) (Igdecik formation of Şimşek, 1985a). Towards higher ground there is Kızılburun formation going down to 807 m. This strata consisted of limestone, sandstone, conglomerate and siltstone interbedded (1950-1143m). Below Kızılburun formation, limestone strata was found (1950-1775 m). At 1615 meters, a fault zone was cut and the loss of mud circulation was found to be 300 m3. Above Kızılburun, there is Sazak formation (between 1143-814 m), consisted of limestone and had a reservoir temperature of 96°C. This zone had been passed by casing. Similar zones had measured at 200°C in the reservoir at Kızıldere and 125°C at Tekkehamam geothermal fields. At the top of the Sazak Formation, clay strata was discovered (814-60 m). The X-ray diffraction analyses confirmed illite and kaolinite. At all levels, minerals of calcite, secondary quartz, pyrite, pyrrhotite were seen. Fault slicken-side was discovered at all levels. At the uppermost section of the MDO-1 well (60-00 m), coarse conglomerate, sandstone layers were seen. The geology of the field and the geological section of the well confirm the same faulted tectonic structure. The main fault lines are in the direction of E-W, secondary fault lines are in the direction of N-S, and NE-SW. Fault lines cut with drilling MDO-1, are E-W directed. When the surface measurements from these two faults were correlated with the depth of the two faults drilled in the MDO-1 well (1615, 2050m fault zone), listric faults were easily seen.”

Figure.11: Geological Map and Section of Gerali-Sarayköy Area (after Karamanderesi and Ölçenoğlu, 2005) Field observations were done at whole of the Sarayköy Geothermal Field (SGF) a new geological map was compiled (Fig.12). As can be seen at this map, nearly half of the area covered by Quaternary Alluviums (Al, white colored) and Holocene aged terrace deposites (QT, grey colored). Pliocene aged Tosunlar fm. marls and sandstones (plT, yellow colored) are being outcropped especially at SE’ern side of the SGF, between Kumluca and Gerali villages as slightly tilted blocks influenced by young and recent faults. Most of the remaining part of SGF covered by Upper Miocene aged Kolonkaya fm. marls, marly and sandy limestones (mK, orange colored). Lower Miocene Sazak fm. limestones and underlying gypsiferous subunit can outcropped only at SW’ern corner of the SGF(mS and j, green and blue colored). It is already known that Metamorphic Basement rocks spread whole of the area at 200 to >1000 m depths. Similarly, Lower Miocene aged Kızılburun and Sazak formation rock units are also spread whole over the SGF, under the young cover. SGF area is furnished by a set of gravity faults extending between WNW-ESE directions. These faults swarm looks more obvious at the western half of the SGF. Geophysical surveys propve that similar structural framework is also valid under the Quaternary sedimentary cover. Typical geological cross sections and subsurface geological model will be given at following sections, after compilation and evaluation of several information.

Figure.12: Geological Map of Sarayköy Geothermal Field (SGF)

II.3. Structural Geology A “Regional Lineament Map” has been prepared by using satellite images during ENEL(1998) study. This map obviously shows regional texture clearly. The region looks mpostly aeffected by NE-SW and WNW-ESE oriented lineaments.Çürüksu Graben structure laid in conform with these orientations; while, Büyük Menderes Graben structure obliquely intersect these.

Figure.13: Structural Lineament Map of the Region (after ENEL et.al., 1998)

Kaymakçı(2006) has compiled a brief structural evolution of the region: “The West Anatolian Horst-Graben System (WAHGS) extends from the Aegean Sea to central Anatolia and it is one of the most rapidly deforming regions in the world. It is characterized mainly by E–W trending major horsts and grabens, and NW–SE to NE–SW oriented relatively short and locally suspended cross-grabens, contained within the major E–W trending horsts. The tectonic origin, age and structural development of these structures and direction of extension in the region are hot issues in the international literature. Four different models have been proposed for the origin and age of these structures. Nevertheless, two different processes dominate in the Aegean region, including western Anatolia. These are the westward extrusion of the Anatolian Block and the N–S extension resulting from subduction of the Eastern Mediterranean crust below Greece, the Aegean Sea and Turkey. Roughly, the North Anatolian Fault Zone (NAFZ) forms the northern boundary of the extensional area, whereas the southern boundary is rather diffuse and may reach as far south as the Crete-Rhodes depression and the Hellenic and Pliny-Strabo trenches. The major, roughly E–W trending basins in the WAHGS from north to south are Bakırçay, Gediz, Küçükmenderes, Büyükmenderes and Gökova grabens. These basins are very well defined by horst-graben morphology that may reach up to 200 km in length, where the main peaks of the horsts may reach up to 2 km in height, while the graben floors lie at about sea level. The Denizli Graben is situated in an area where three major E–W grabens approach at their eastern ends. Thus, it forms the eastern continuation of the Büyükmenderes Graben and is separated from the Gediz Graben by a topographic high, about 10 km long, around Buldan and from the Küçükmenderes Graben by a high about 40 km long, although some of the basin-bounding faults are shared by these grabens, such as the Buldan and Buharkent faults which traverse both basins. The Denizli Basin as a whole is bounded in the north by the Çökelezdag Horst and in the south by the Babadağ and Honazdağ Horsts. In the central part, it is traversed by one of the faults of the Laodikia Fault Zone that also controls the northern margin of the Acıpayam Graben. It is a NW–SW elongated basin approximately 50 km long and 25 km wide, and comprises two Quaternary sub-basins, namely the Çürüksu Graben in the north and the Laodikia Graben in the south, separated by a large basin-parallel topographical high along which Late Miocene–Pliocene fluvio-lacustrine deposits are exposed. The Çürüksu graben is controlled in the north by the Pamukkale Fault Zone and in the south by the Laodikia Fault Zone. The Laodikia Graben is controlled by one of the branches of Laodikia Fault Zone in the north and Babadağ Fault in the south. To the east of Denizli town

center, north of Honaz and around Kaklık, the Denizli Basin has a staircase geometry delimited in the south by the Honaz and Kaklık Faults, around which the main boundary faults of the NE–SW trending Baklan and Acıpayam grabens interfere. Extension in the region commenced in the Late Miocene and has continued, possibly without a break, and is presently active.”

Figure.14: Structural framework at Denizli Basin (after Kaymakçı, 2006)

Figure.15: Structural Model of Denizli Basin (after Kaymakçı, 2006)

Şimşek(1985a) has modeled the regional structure as given below with succesive grabens and a horst.

Figure.16: Structural Model of the Region (after Şimşek, 1985a)

Kaymakçı(2005) has analyzed the stres orientations at Denizli Basin, including Sarayköy area too. Author explains his work as “Paleostress orientations and relative paleostress magnitudes (stress ratios), determined by using the reduced stress concept, are used to improve the understanding of the kinematic characteristics of the Denizli Basin. Two different dominant extension directions were determined using fault-slip data and travertine fissure orientations. In addition to their stratigraphically coeval occurrence, the almost exact fit of the s2 and s3 orientations for the NE–SW and NW–SE extension directions in the Late Miocene to Recent units indicate that these two extension directions are a manifestation of stress permutations in the region and are contemporaneous. This relationship is also demonstrated by the presence of actively developing NE–SW and NW–SE elongated grabens developed as the result of NE–SW and NW–SE directed extension in the region. Moreover, stress ratios plots indicate the presence of a zone of major stress ratio changes that are attributed to the interference of graben systems in the region.”. Westeway(1993) explains this structural framework in extensional textonics concept as, “The Denizli region contains one of the easternmost Neogene sedimentary basins in the part of western Turkey that takes up SSW extension. This isolated active normal fault zone, which contains closely spaced en echelon normal fault branches, is investigated using field measurements of fault exposures and tilted sediments, and seismological observations, as a case study to address its style of extension. The Denizli basin is no more than -1 km thick and has accommodated up to 4 km of extension. Substantial (-20 °) sediment dips are readily explicable assuming extension is accompanied by distributed vertical simple shear, with initial and present-day dips of the main normal faults that control extension most likely 54-57 ° and 45-50 ° . Other aspects of the form of this basin require regional uplift at -0.1 mm yr -I, providing the first indication of major tectonic elevation changes in this actively-extending region that are not directly related to throw on normal faults.” Observations of normal faults and dips of Neogene beds in the Denizli basin are assessed for their tectonic significance. The limited extension and low sediment thickness, combined with the relatively steep dips of some uppermost Miocene sediments, up to -20°, preclude extension having been accommodated by rigidbody rotation of normal-fault-bounded blocks. The evidence is consistent with their tilting having involved distributed vertical simple shear instead. This view, which requires beds to tilt more than adjacent faults, indicates an initial

normal fault dip no greater than ~57 °. Southsouthwestward extension across this basin decreases from ~4 km near its western end to <1 km near its eastern end, consistent with the regional eastward decrease of extension in this sense across westernmost Turkey. Effects of regional uplift at ~0.1 mm yr-1, which has accompanied this extension, can be distinguished from elevation changes directly caused by normal faulting(Westeway, 1993). II.4. Seismicity Demirtaş et.al.(2001) processed the earthquake events occured between February and October of 2000. It is obivous that most of the events are related with graben forming faults.

Figure.17: Ms>2,7 Earthquake events at surroundings of Denizli between February and October 2000

(after Demirtaş et.al., 2001) Authors comment that Denizli these earthquakes most probably generated from the faults of Honaz-Kaleköy-Özerlik-Sarayköy, Honaz-Karakova and Pamukkale Fault between Honaz-Pamukkale-Karahayıt which cross near NE of the Denizli Basin. Displacements at Babadağ at Honaz faults are more than 1250 m, totally. Aydan et.al.(2005) has investigated the multiparameter changes in the earths crust and its relation with seismicity. The measurements have been taken in five minutes of interval. The measured parameters are temperatures of thermal waters, electric field measurements from soil and rock, acoustic emission numbers of a bubling sink hole of Tekkehamam thermal spring area and on the fault plane of Honaz. During Çay-Eber earthquake in 2002 and Buldan earthquake in 2003, some changes in temperatures of thermal waters, electric field value and acoustic emission numbers were measured at the multi-parameter stations of Denizli. The results showed that there is a strong relation between the earthquake activity and the changes with in the earthcrust in Denizli Region.

III. THERMAL MANIFESTATIONS III.1. Thermal Springs and Pools There are several hot water springs and some hot water pools in or around the Sarayköy Geothermal Field. Most of these are situated at the western neighbouring area of the field. These are called as Tekke Hamam, İnaltı, Demirtaş, Babacık And Kabaağaç thermal sites. But, some water discharges are also situated at NW’ern corner of the site. These are called as Gerenlik, Uyuz Hamam or Kokar Hamam thermal site and licensed to the Umut Thermal facilities and are listed below.

Owner Name Symbol Coordinates Temp. Outp. X Y Z °C lt/sec.

Umut Therm. Uyuz Hamamı K-1 0666827 4198886 83,5-90 5

Umut Therm. Sazlı Kaynak K-2 0666828 4198816

Umut Therm. Uyuz Hamamı K-3 0666877 4198783

Umut Therm. Large Sulphur K-4 0666732 4198763

Umut Therm. Kokar Hamam K-5 0666747 4198739 98

Umut Therm. Kokar Hamam K-6 0666732 4198736

Çağlar(1948) investigated these Gerenlik springs and Tekke Hamam springs together and noted their temeperatures as between 82-97°C. Springs at westernly neighbouring region are situated at İnaltı, Tekke Hamam, Demirtaş, Babacık and Kabaağaç spring sites. According to Çağlar(1948) İnaltı spring has temperature of 60°C; while, the temperatures of the Babacık and Kabaağaç springs are 43°C and 62°C respectively. Akkuş et.al.(2005) gave the temperatures as 62°C for Babacık springs, 40-100°C for Demirtaş springs, 17 thermal springs of Tekke Hamam as 29-97,2°C and 4 springs of İnaltı-Uyuz 83,5-98°C. They mentioned the total outflow as about 30 l/sec. Karamanderesi(2002) points to the existence of abundant thermal water springs at Gerenlik territory. Author gives some information on Local Spring, Small Pool, Gas Vents, Small Sulphur Pool, Mud Pool and Large Sulphur Spring, Large Pool, gerenlik Lake. Şimşek(1984) shows their locations in relation with Kızıldere wells roughly, below (Fig.18).

Figure.18: Thermal springs and wells at two sides of the Graben (after Şimşek, 1984)

III.2. Hydrothermal Alterations ENEL et.al.(1988) has studied some rock samples taken from one of the Kızıldere wells and conclude that “From the hydrothermal mineral viewpoint the data are interesting; they confirm the presence of hot fluid circulation whose maximum temperature is approx. 200°C. This evaluation was based on the confrontation of the data of this field with published data of other geothermal fields. The presence of the following hydrothermal minerals are reported: clay minerals, calcite, oxides (mainly hematite), silica,chlorite, sericite and/or talc.”. At south of the Sarayköy (Gerali) Geothermal Field, low temperature (29°C) fluid coming from shallow wells at Gerali village, as well as high sulphur content at Kükürt River and Acısu village were clearly seen as surface manifestations (Karamanderesi and Ölçenoğlu, 2005). Karamanderesi and Ölçenoğlu(2005) has studied the hydrothermal alterations of drill cuttings. Their determinations are being excerpted to below. “60.00-814.00 m Zone is covered with grey clay. Hydrothermal alteration zone is illite zone. 584-588 m to 692-698 m various coloured clay, heavy pyrite and as a secondary mineral, pyrrhotite have been detected. Additionally, remains of plant, organic materials, pyrite, calcite, and very small amount of silica have been seen at 798-799 m level. The samples from the level of 806-810 m showed; gray clay, siltstone and the traces of heavy micro crystalline pyrite, chalcopyrite, secondary calcite and quartz. 814.00- 1143 m, Sazak formation. Light brown and milky brown limestone have been detected by the microscopic analyses. Between 878-896 m, secondary silica and calcite as well as traces of manganese have been detected, under the microscope. Below the 1143-m level, change in colourization and formation as well as kaolinization was observed. 1143-1607 m Kızılburun formation was clearly defined. Secondary pyrite, calcite, quartz and clay matter can be seen in the conglomerate and sandstone layers. Scattered green layers appear to be relict that resulted after the chlorization. The cuttings from 1181-1184 m layer show the slickenside, clay and heavy pyrite remnants. At the 1712-1766 m level, maroon clay fault lines, secondary quartz veins and calcite fragments can be seen in the Kızılburun Formation. Petrographic analysis of 1774-1780 m cuttings: The main material samples from this level contained, limestone fragments, sparritic, micritic and mosaic patterned quartzite. Traces of muscovite and amphibole were noticed as well. In addition; chert fragmented metamorphic rocks, quartz-micaschist, quartzite-schist, quartz-calc

schist which coloured by ferrous-oxide have been detected in the microscope. In the microscopic sample, quartz (mono crystalline/Polly crystalline), biotite and muscovite have been detected. The biotite must have been coloured green as a result of chloritization. Petrographic analysis of 1834-1836 m cuttings from this level contain; micritic limestone fragments, chloritization, silicified ferrous oxide fragments, slate, schist, quartzite, quartz, feldspar, garnet and opaque minerals. In the cuttings from 1862-1900 m strata; calcite, dolomite, quartz, feldspar, muscovite and kaolinite have been detected by the X-ray diffraction analysis. Menderes Massif metamorphics have been studied in two separated zones as follows; Zone 1 : 1950-2050 m. Marble zone, Zone 2: 2050-2401 m. Mica schist zone. At the 1950-2036 m. Strata, milky white marble have been confirmed as the top level. Additional studies with the X-Ray diffractometer have resulted in minerals such as calcite, dolomite, quartz possible various alkali feldspar (albite) muscovite and kaolinite. Various thin section samples have shown mica-quartz schist, quartz-mica-calc schist, quartzite, and silicified rock fragments as well as carbonitized rock pieces. The X-ray diffractometer analysis have confirmed the same results as above. At the 2036-2050 m different mineral composition have been noticed. The X-ray diffraction studies have discovered calcite, dolomite, quartz, feldspar, chlorite, simectite (montmorillonite), mixed clay (possibly mica-simectite), amphibole (hornblende), muscovite and kaolinite respectively. The 2050-2401 m Zone 2. 2050-2041 m mica schist zone. These zone cuttings contained quartz-mica-calc-schist, quartz-calc schist, micaquartz- schist, quartzite, mica-quartz-schist, mica-schist, and very small amount of epidote schist. The mineral compositions of the cuttings have been discovered as quartz, mica (muscovite/biotite), chlorite, simectite(montmorillonite) and kaolinite. This is the second alteration zone discovered in the drilling operation.” On other side, Özgüner et.al.(1977) has studied the sulphur occurences at Tekkehamam. They conclude that the “the origin of the Tekke Hamam sulphur is hydrothermal. Most promising sulphur accumulations will be located where intersection lines of the fault planes in the ground are most densely populated and closed to each other.” III.3. Temperature and Gradient Anomalies Demirören(1969) gave some thermal gradient measurement results for Kızıldere and Tekke Hamam areas(Fig.19). Measured temperature gradients rise up to 3°C/10 m level.

Figure.19: Geothermal Temperature Gradient Measurement Results (after Demirören, 1969)

IV. GEOPHYSICS “Ekingen, 1970”, “Turgay, et.al.(1980)”, “Özgüler et. al. (1983)”, “Sülün et. al. (1985)” groups from MTA have made several geophysical resistivity and gravity surveys at Denizli Buldan-Pamukkale fields and at southern Sarayköy Geothermal Field seperately. Recently Yavuz Alakuş made a study for apparent resistivity for the length of AB/2=2000. The electric prospected in 24 Vertical Electric Sounding (VES) by the Schlumberger quadripole(Karamanderesi, 2002 and 2005). Özgüler, et.al.(1983) compiled the results of geohysical studies conducted at the Denizli Basin. ENEL et.al.(1988) study covered some resistivity and MT soundings and some seismic reflection profile measurements (Fig.20).

Figure.20: Locations of the ENEL et.al.(1988) surveying points

IV.1. Gravity Tezcan(1967) produced a bouguer anomaly and a gravity second derivative maps of the region, which also covers the Sarayköy Geothermal Field. As can be seen at Fig.21 Bouguer Map shows that the SGF is located at the southern half of a E-W trending through. Beside this the western quarter of the field is situated at a NW-SE trending steep zone of the Basement. Similarly the Gravity Second Derivative Map (Fig.22) exposed the local structure in more detail. The western zone uplift is seen as a typical horst extending between N and S directions and shaped by N-S trending faults; while, its northern part bounded by two NW-SE and NE-SW gravity faults. This structure can be called as “Tırkaz Horst”.

It is clear that the location and trend of the eastern side of the Tırkaz Horst are very similar with the observed fault structures at surface. The eastern 1/3 of the SGF looks also rised by a NNE-SSW trending structural discontinuity. These structures are well matched with findings of other geophysical surveys.

Figure.21: Gravity Bouguer Map of the Region

Figure 22: Gravity Second Derivative Anomalies at and Around the Sarayköy Geothermal Field

IV.2. Resistivity Most of the Sarayköy Geothermal Field area is covered by resistivity sounding locations. These surveys have been done at several studies at between 1985-2002 years (Figh.23).

Figure.23: Locations of the Geophysical Resistivity, MT and Seismic Measurements

Tezcan(1967) survey exposed the distribution of low resistivity zones for different depths (Fig.24-26) and a depth to resistive basement map (Fig.27).

Figure.24: Low(blue) and High(red) Resistivity Zones for AB/2=300 m

Figure.25: Low(blue) and High(red) Resistivity Zones for AB/2=500 m

Figure.26: Low(blue) and High(red) Resistivity Zones for AB/2=(800-900-100) m

Tırkaz Horst emerges with its very high resistivities and this had been attributed to the sulphur accumulations, beside the structural rising position. Resistive Basement Map (Fig.27) also sharply show this uprising structure. Low resistivities start especially from the NW-SE trending fault zone at NE of the Tırkaz and clearly migrate through to NE with depth. This low resistivity zone being larger with depth and coaleces with the anomaly zone of Kızıldere Field. Demirtaş covered horst also emerges with moderate resistivities as a barrier between Tekkehamam-Sarayköy Fields and Kızıldere Field.

Figure.27: Resistive Basement Depth Map

Sülün et.al.(1985) study also produced similar anomaly maps fort he eastern part of the Sarayköy Geothermal Field(Fig.28-30). These anomalies also well matched with Tezcan(1967) ones.

Figure.28: Resistivity Anomaly Map for AB/2=850 m

Figure.29: Resistivity Anomaly Map for AB/2=1000 m

Figure.30: Resistivity Anomaly Map for AB/2=1200 m

Five of the ENEL et.al.(1988)’s VES soundings fall into the Sarayköy Geothermal Field, beside these. Recent local surveys at around Gerali and Umut Thermal sites also gave similar results. IV.3. MT ENEL et.al.(1988) has conducted a Magneto Telluric survey at and between Sarayköy, Tekke Hamam and Kızıldere Fields. Total 25 soundings were made. 5 of these are located in or the vicinity of the Sarayköy Geothermal Field (Fig.20). MT8 near Umut Thermal facilities show that the top of first resistive layer is at 1200 m depth. It is at 650 m depth at MT12 close to Hasköy at NE’ern corner of the SGF. This depth can’t be determined at MT9 at northern border of SGF near Karakıran village. Resistive layers couldn’t be determined also at MT25 at between Tırkaz and Kumluca villages and at MT24 near Tekke Hamam.

Bayrak et.al.(2009) reworked ENEL(1998)’s MT data recently. These data were modeled using two-dimensional inverse techniques. The main findings are: (1) presence of wide conductive regions with very low resistivity (<20 ohm m) were imaged at depth of ~2 km, extending to maximum ~5 km depth, and these conductive regions signify potential geothermal resource in the area, (2) presence of deep conductive regions (<75 ohm m) at a depth from ~30 km to 40 km, which reflects shallow asthenosphere, were correlated with the presence of high enthalpy geothermal Figure.31: An MT Profile Crossing From SGF

system and its heat source. One of their model profiles which crosses from the investigated Sarayköy Geothermal Area is excerpted below. As can be seen from this model a two fold depression is situated at the region.

IV.4. Sesismic Reflection ENEL et.al.(1988) has made also seismic reflection profile measurements over four lines. One of these, Line 88KD 1 passes from the NW’ern part of the Sarayköy Geothermal Field. This line is crossing from TH-1 well and owing to the known section of strata at this well found very suitable for interpretation. Interpretations and Section are being given below.

Authors conclude that there is “400 m vertical throw over 1100 m horizontal distance on the profile 88KD1. Along the axis of the graben, travelling eastward from the fault F1, the basement depth ranges from about 1200 m up to about 950 m in the central part, down to 1200 m and more toward the east. The central part, between the Kızıldere and Tekkehamam is occupied by a transverse horst.”

Figure.32: Sesimic Profile Crossing from SGF and TH-1 Wellş

IV.5. Well Logs Several well logs had been produced during (Demirören, 1969) studies for the temperature gradient measurement holes. It can obviously seen from these logs (Fig.33-36) that Tosunlar fm and Sazak fm can easily be separated by these logs, as cover and first reservoir units.

Figure.33-36: Geophysical Well Logs Taken at temperature Gradient Measurement of Tekkehamam

V. BOREHOLES There are several geothermal wells constructed at this site. General information of these wells are being given below.

Table. : Information on Geothermal Wells at or Near the Sarayköy Geothermal Field

Owner Name Year Coordinates Depth Temp. Outp. X Y Z m °C lt/sec.

MTA TH-1 1968 151,15 616,5 116,1

TH-2 19976 0660625 4200500 131,87 2001,2 171

Local State A. İÖİ-1 0663981 4196920 120 30

Değirmenci MDO-1 2003 0667475 4197600 2401(2119,5)120 50

Umut Therm. S1 2001 0660770 4198853 115(149) 120 20

S2 2001 0660520 4198838 202(154) 100 25

S3 2001 0660620 4198806 39(169) 100 10

S4 2002 0660654 4198730 61(164) 120 10

S5 2002 0660607 4198870 253(155)1 110 20

V.1. MTA Wells TH-1 well was constructed at near the Sarayköy Geothermal Field at 1968. Its depth is slightly more than 600 m. It was terminated just after the entering into the Metamorphic Basement. Maximum temperature measured at this well is 116°C. TH-2 well was completed at 04.01.1998. Below the 70 m thick alluviums Tosunlar fm. Layers were drilled down to 325 m’s. Then, 220 m thick Kolonkaya fm., 55 m thick Sazak fm. and 215 m thick Kızılburun fm. layers were drilled down to the top of Metamorphic Basement at 815 m depth. Basement consisted of marble at top and schists down to well bottom(Fig.37). After several well hydraulic tests this well couldn’t be choosed for either production or reinjection purposes. V.2. MDO-1 Well According to Karamanderesi and Ölçenoğlu(2005) “the well has been drilled down to 2120 meters in depth and than completed at this depth. Later the well was deepened down to 2401 due to the request of the owner. During drilling at every 2 meters cuttings were taken and properly labelled. The well was cased as follows: 0.00 – 100 m 20” casing, 0.00 – 488.50 m,

                                                            1 Bracketed lengths are registered, others are from well constructors 

Figure.37: TH-2 Well Log

13 3/8” casing, buttress thread, 0.00 –1452 m 9 5/8” casing, buttress thread, 1452 – 2119 m. Slotted casing. Geological stratification of Gerali geothermal field from the bottom to top is as follows; at the bottom biotite-chloritecalc-quartzschist. Above them marble and metamorphic basement of Menderes massif take place. Then Miocene and Pliocene sediments of 1950 meters thickness are found. Geological section is divided into two different hydrothermal alteration zones. At the well log too many fault zones have been seen. Faults cutting sedimentary limestone and marble are the main production zones. During the drilling, after 600 meters alteration has begun. Loss of mud circulation started after 900 meters. At the 1607-1619 meters, total of 300 m3 loss of mud circulation has occurred. After this level, the drilling has been continued; partial loss and alteration have been inspected continuously. After the well completion tests, 125°C bottom hole temperature was measured by Amerada temperature gauge. Production of the well was determined at 50 lt/sec. At production tests the deposition of CaCO3 scaling was seen from the surface down to 120 meters in depth.”

Figure.38: Well Log of the MDO-1

V.3. İÖİ Well Denizli Provincial Administration has tried to construct a hot water well near the Kumluca Village at center of the Sarayköy Geothermal Field. But the well has been abandoned at 120 m depths after the entrance of 30°C water into the hole. V.4. Umut Thermal Wells There are five wells drilled for thermal water propduction at the Umut Thermal area(Fig.’s 39-43). One of these had been abandoned(S3). Two of these are being used regularlarly to feed the facilities (S1 and S2). Two others are being protected for emergency. Karamanderesi(2002) gave some information on S1(KB-1) well. This well was constructed at November 2001. Its depth was 115 m. There is some information that this well was deepened at recently down to about 250 m’s(?). The well was furnished with 10 ¾” diameter casing down to 73,75 m. Remaining deeper part of the well is bare. 20-25 lt/sec water and steam with 120°C temperature was outflowed from the well. Bare section of the well consists of Sazak fm. limesyones and deepend part consists of gypsiferous carbonates. Hydrocarbonecaus material hgas been blown out at 120 m depths with some geothermal brine (with 120°C temperature) during construction. This material was investigated by Gürgey et.al. (2005).

Figure.39: S1 (KB-1) Well Log

Figure.40: S-2 Well Log

Figure.41: S3 Well Log

Figure.42: S4 Well Log

,

Figure.43: S-5 Well Log

V.5. Well Tests Inspite of the existence of 9 wells at or the vicinity of the Field, only two of these wells has been tested for their hydraulic properties. These are TH-2 MTA well and MDO-1 well tests. Some new tests are just conducting at some Umut Thermal wells. Çetiner(1999) gave the result of TH-2 well tests(Fig.44). Production, static temperature and static pressure measurements, dynamic temperature and dynamic pressure measurements, water loss, pressure build up, single rate injectivity and multi rate (5 steps) injectivity tests were applied. Productive zone has been interpreted as at 1100-1400 m interval. Productive zone according to the water loss test is located at 1100-1200 m interval. Author estimated the Injectivity Index at 1300 m as 1,9x10-7 m3/sec/kPa. Transmissivity was estimated at 1200 m depth as T=4,15x10-12 m/sec. 42 m3/h output rate was estimated fort his well.

Figure.44 : TH-2 Well Test Results (after Çetiner, 1999) Yeltekin and Erkan(2000) discussed these results of tests done at TH2 well. Its maximum temperature has been determined as 168,02°C at 1980 m dewpth. Its output was 42 tonnes per hour at 3-4 psi well head pressures. Reservoir horizon is at 1200-1300 m’s depths. Hydraulic conductivity of this layer was determined as kh= 1,2-3,0 darcy.m. Its productivity index is 2,482 (t/h)/(kg/cm2) and injectivity index is 3,524 (t/h)/(kg/cm2).

MOO-1 well has been tested by MTA as subcontructor after the completion. Its temperature logs are being given below(Fig.45).

Figure.45: Temperature Measurement Results at MDO-1 Well

Yıldırım(2008) made some inhibitor tests against the scaling at Umut Thermal wells.

VI. GEOCHEMISTRY VI.1. Hydrogeochemistry Çağlar gave one representative chemical compositions for each of Kokar Hamam(Gerenlik), Tekke Hamam, İnaltı, Babacık and Karaağaç thermal spring groups. Namoğlu(1997) has also gave another composition report from a Tekkehamam spring. Özgür(2002) has also studied the Kızıldere thermal waters together with other waters of the region. Karamanderesi(2002) gives two chemical analuysis results, one from TH-1 well and another one from Gerenlik Lake. Similarly, Şimşek(2003) gave a chemical analysis for Tekkehamam spring. Comprehensive geochemistry study of ENEL et.al.(1988, app.3) gives chemical compositions of Kabaağaç Spring, Demirttaş Spring, İnaltı Spring, TH-1 well and seven Tekke Hamam spring waters. They have conclude that there are four type of waters at the region.

Waters have B content between 9,80-20,00 ppm and SiO2 contents between 120-375 ppm (it is 210 ppm at Gerenlik Lake at investigated site). Alkali and HCO3 contents of the waters from southern side of the graben are lower than Kızıldere waters, while SO4 contents are higher. Yıldırım and Güner(2005) have compiled a number of chemical compositions fo the cold and thermal waters from the region as below given Piper Diagramm.

Figure.46: Piper Diagramm of Chemical Composition of Various Thermal and Cold Waters

(6-Babacık, Demirtaş; 7-TH-1; 10-Tekkehamam Springs) (after Yıldırım and Güner(2005) Gökgöz(1998) processed the compositions of 6 thermal water samples from the south of graben (TH-1 after Yıldırım et.al.(1997) and Demirtaş, Babacık, Tekke Hamami İnaltı, Gerenlik after Şimşek(1982)). Well waters from Kızıldere stay at fully equilibrated zone, while the Tekkehamam spring waters fall to the partially aquilibrated waters zone at Giggenbach Diagram with Kızıldere spring waters.

Figure.47: Tekkehamam and Kızıldere Water Compositions at Giggenbac Diagramm

Author has prepared Cl-SO4-HCO3 and Cl-Li-B diagrams to show the relations of different waters. Tekkehamam waters look as “steam heated waters” from “younger hydrothermal systems” owing to the absorption of high B/Cl steam together with Kızıldere waters; but, clearly stay separate from them at Cl-Li-B diagram(Fig.48).

Figure.48: Cl-SO4-HCO3 and Cl-Li-B Diagrams

Çetiner(1999) discussed total of 26 water analyses of MTA, ENEL and DEÜ, 8 of which have been collected from western, central and eastern Tekke Hamam, Demirtaş spring, TH-1 well, Kokar Hamam spring and Menderes River. The waters of Tekke Hamam were classified as “alkaline bicarbonate sulphate” and TH-1-Demirtaş-Kokar H. and Menderes River waters as “alkaline earth sulphate bicarbonate” type (after ENEL et.al.,1988). Author, said that “Southern part of the Kızıldere geothermal field is the outflow zone. There are many hot springs associated with tyhe southern field margin faults. In this zone conductive cooling, steam and gas loss by decreasing pressure, dilution with the ground water are effective.” Özgür(2002) concludes that, “Precambrian to Cambrian metamorphic and Pliocene sedimentary rocks are distinguished from one another by enrichment patterns for Hg, Sb, As, Tl, Ag, and Au, and depletion patterns for alkaline and alkaline-earth elements in connection with degree of hydrothermal alteration. The thermal waters

have surface temperatures of up to 100°C and reservoir temperatures from 148 to 198°C in the Sazak formation and from 200 to 212°C in the İğdecik formation. Hydrogeochemically. Kızıldere thermal waters are of the Na-HCO3-(SO)4 type. Metalloids of As and Sb and some trace elements (e.g., B and F, indicating high temperature water-rock interaction), are found in high concentrations.” Analysis of a water sample taken from the MDO-1 well is shown below (Karamanderesi and Ölçenoğlu, 2005).

VI.2. Gas Chemistry Güleç(1988) has studied the Hellium-3 isotope distribution in the thermal water samples from Western Anatolia and gave an analysis result for also a Tekkehamam gas sample.

R/Ra values coincides with either several subduction or extensional zones. Güleç (1988) interpretes the He-3 distribution at all over the Western Anatolia waters as, the lack of any correlation between the distribution of mantle-helium and surface volcanism suggests that helium, now degassing from mantle, has most probably entered the crust in association with the melts emplaced at deeper levels. The fault systems of the present extensional tectonics are thought to have had an efficient role in the escape of helium to the surface through the brittle parts of crust. ENEL et.al.(1988) gives three gas analysis for the Tekke Hamam spring discharges. According to their results gas compositions vary between CO2 %96,00-98,25; H2S %0,179-1,71; H2 %0,0017-0,027; CO %<0,0001-0,0002; CH4 %0,0792-0,357; O2+Ar %0,0380-0,267; and N2 % 0,947-1,68. Wiersberg, et.al.(2009), gives the results of a geochemical gas monitoring experiment applied from November 2007 until October 2008 which was performed in Tekke Hamam. All gas

samples mainly consist of CO2 (>95 vol.-%), followed by N2, CH4, O2, H2S, Ar, H2 and He. O2 (<0.3 vol.-%) can be attributed to atmospheric contamination during sampling/monitoring. Samples from Tekke Hamam show generally higher concentrations of H2S, He and CH4 than those from Kızıldere. 3He/4He ratios are higher at Tekke Hamam (2.6-2.9 Rα) compared with Kızıldere to (1.1-2.1 Rα). In the Kızıldere geothermal field, a SW-NE reaching trend to lower Rα values could be observed. Furthermore, the Rα values roughly correlate with the well depths, showing higher Rα values in deeper wells. A possible explanation could be mixing between a shallow fluid reservoir with lower 3He/4He ratio and a deeper reservoir with higher one. Different types of variation in the gas flow and gas composition could be observed during gas monitoring: longterm changes in the gas composition, daily variation and short-term fluctuation. From these, the daily variation seems to correlate with the temperature. Data evaluation is ongoing to understand weather the changes in the gas composition can be attributed to seismic events or to meteorological factors. VI.3. Isotope Chemistry Çetiner(1999) has collected 4 isotopic analyses from the southern side of the graben after Filiz(1982) and ENEL et.al.(1988) as below:

Sample location δ18O δD δ3H

Tekke Hamam -5,77 -59,0

Tekke Hamam -6,52 -55,9 <1,6

TH-1 -8,65 -62,6

Kokar Hamam -6,89 -54,0

δ18O, δ2H, δ3H, 14C, δ34S-SO4 and δ18O-SO4 isotope analyses were also realized by Yıldırım and Güner(2005). “The deuterium/altitude relation of the shallow ground waters shows that the Kızıldere and Tekkehamam field’s thermal waters are approximately fed from 1300 - 1900 m.a.s.l. The δ34S-SO4 and δ18O-SO4 isotope analysis, reveal that the origin of the SO4 ion in Tekkehamam and its surrounding thermal springs, is from the dissolution of gypsum layers of the Pliocene aged Kolonkaya Formation. Due to the existence of high temperature in the reservoir, exchange between the δ18O-SO4 and δ18O-H2O isotopes takes place in the Kizildere’s geothermal reservoir fluid. The rate of the exchange is calculated to range between 46 % and 84%. The 14C isotope calculation results refer to 22000 - 31000 years of turnover time for the geothermal fluid of the area (Yıldırım and Güner, 2005).”

Çetiner(1999) had estimated elevations of recharge area as 935-1450 m’s.

Figure.49: Oxygene Isotope Enrichment at Geothermal WQaters of Denizli

Özgür(2002) interpreted the isotope data as “Isotopic data reveal that Kızıldere thermal waters do not contain measurable 3H. Conversely, some nearby thermal springs with temperatures of up to 88°C contain atmospheric and anthropogenic 3H (up to 6.5 TU). Therefore, there is evidence for a mixing process between the fresh groundwater and deep thermal water. The Kızıldere thermal waters are of meteoric origin. Stable isotope values of δD and δ18O show that the mixed groudwater-thermal water systems lie along the meteoric water line, whereas high temperature, deep grouadwater systems deviate from th meteoric water line in showing a water-rock interaction at high-temperature conditions. These data agree well with the results of hydrogeochemical analyses indicating intensive water-rock interaction and reactions with silicates. Overprinting by reactions with crystalline rocks was intensified by outgassing of magmatic CO2 and H2S, proven by isotope analyses of δ13C, δ34S, and δ11B. Although intense geochemical near-surface reactions occur, the geochemical features of high-temperature, water-rock interaction dominate the chemical and isotopic characteristics of the studied waters.” Similarly Özgür et. al. (2005) concludes that the “stable isotope compositions (δ 18O and δ 2H) in thermal waters show that the groundwater and mixed groundwater-thermal water samples lie along the meteoric water line whereas the high temperature thermal waters deviate from the meteoric water line indicating a fluid-rock interaction under high temperature conditions.”

Figure.50: Oxygene Enrichment at Denizli Thermal Waters

Isotopic composition of a Tekkehamam water was given between others by Şimşek(2003).

Figure.51: Oxygene Enrichment at Denizli Thermal Waters

VI.4. Geothermometers ENEL et.al.(1988) concludes after the analysis that,

Gökgöz(1998) estimated some reservoir temperatures from the available chemical analysis.

VI.5. Scaling and Hydrocarbon Occurences Karamanderesi and Ölçenoğlu(2005) gave some analysis results on the scaling material from inside of the MDO-1 well. According to the authors, “in Turkey, all of the geothermal fields, including the MDO-1 well in Denizli-Sarayköy (Gerali) geothermal field have scaling problems. Denizli (Kızıldere) geothermal scaling analysis have shown to be composed of CaCO3 (% 54.96-78.20), SrCO3 (%15.68-19.52) and BaCO3 (%. 19-%0.57). Whereas Germencik (Ömerbeyli-2 well) geothermal scaling analysis have shown to be composed of SrO (% 27) in one sampling, Sr (% 0.2) in another sampling. MDO-1 well has been worked over for one week. The scaling have been observed from 0-120 m level. The resulting samples have been analysed by MTA laboratories as shown below table. According to comparative calculation between the two samples; the results have been recorded as CaCO3 (% 94.94-95.66), SrCO3 (%1.22-1.23), Fe2O3 (% 0.64-0.49) and BaCO3 as minimum scaling.”

Yıldırım(2008) made some inhibitor tests against the scaling at Umut Thermal wells. Tests were done for KG-1(S1) well water. Tests were done by 6 different chemicals and for 5 different time periods. Capacity of pump limited the well output to 16,416,8 tonnes per hour. Inhibitors were applied at 90 and 150 m depths. “Dipol Pen-water-5401”, Kavram 1040”, “Kavram 1005”, Duraner Varitello Jeo”, “Nalko 1340 HP” and “Nalko PT-42” chemicals were tested for their scaling inhibiting capacities. Results are being given briefly at below. Optimal Dosage Performance Chemicals (gr of inhibiting material under vane at outlet of seconf separator

per tonne of well flow)

Dipol Pen-water-5401 8,3 % 93 %85

Kavram 1040 5,8 %96 %90

Kavram 1005 7,8 %94 %87

Duraner Varitello Jeo 8,3 %93 %85

Nalko 1340 HP 17,8 %82 %68

Nalko PT-42 8,5 %90 %83

Kavram 1040 is being used since this test studies. On other side, some hydrocarbonaceous material had been blown out during the drilling of S5 well at western zone of the site(Gürgey, et.al., 2005). Material has came from 120-132 m depths from Sazak Formation and with 120°C temperature thermal water. The maturation of this material interpreted as result of the hydrothermal activity. The material was generated from a Tertiary source rock with a clay rich lithology, terrestial organic matter deposited in relatively saline and anoxic environmental conditions.

Figure.52: Hydrocarbon Composition Erupted From KB-5 Well

VII. GEOTHERMAL SYSTEM(S) According to the collected and represented information there is a complex geothermal system at the Sarayköy Geothermal System (SGF). This system can be divided to Gerali and Tırkaz sub systems. VII.1. Regional Framework The region hosts several high por low enthalpy geothermal systems. Most warm one of these is the northern Kızıldere Geothermal Field. It situated at the northern side of Büyük Menderes Graben. But there are several hot springs and pools at mid or especially southern side of the Graben. There isn’t any other hydrothermal manifestation at this, southern side of the BM Graben. Thus, the situation of the Tekkehamam and Sarayköy Fields are very unique. Most of the geological, geophysical and geochemical studies verified the existence and extensiveness of the hydrothermal activities underground. These activities look consistent with activities at northern Kızıldere and western Tekkehamam Fields VII.2. Subsurface Geology

Figure.53: Main Structural Discontinuities at SGF according to the Geological and Geophysical

Information

Most of the Field is covered by recent and actual alluviums. So, indirect informations are very important to recognize the Field. Completed well profiles, seismic, MT and resistivity surveys and gravity interpretations shed light onto the subsurface geological structure. There is a N-S directed covered graben structure at mid of the Field. Younger structural lines diverge two side, to NE-SW at east and to NW-SE at western part. These lines bound some horsts at SW and SE of the Field. Thermal manifestations, succesfull wells and low resistivity anomalies are also concordant with this framework. Şimşek(1985) considers the subsurface geological and structural model of the region as given at Fig.54 below. It looks well representing the region; except neglecting a covered mid graben horst between Demirtaş and Karakıran.

Figure.54: Structural Geological Model Proposed for Tekkehamam-Sarayköy and Kızıldere Fields

VII.3. Thermal and Geophysical Anomalies Thermal and geophysical anomalies lie especially at NW’ern and NE’ern quarters of the Field. The resistivity lows being more widespread and migrating to northern and central parts of the Field. The MT and seismic data show that the strata at this depths must be Sazak Formation limestones. The distribution of these anomalies obviously belong to the fault lines. VII.4. Reservoir Characteristics Şimşek(1985a) describes Kızıldere Geotherma reservoir model as, “Drillings in the study area revealed the presence of limestones, marbles and quartzites with permeability characterized by a network of joints, fractures and faults resulting from strong neotectonic activity. A third reservoir can also be hypothesized. At present, there are only two known reservoir formations. The first reservoir: Within the units of the Pliocene, the Sazak Formation represents the first reservoir. Its continuity is, however, broken by lateral facies variations in the formation. The thickness of the limestones in the unit varies and they grade into marls and sandstones laterally and vertically. According to the drilling data in Kızıldere geothermal field, production in wells KD-I, KD-1A, KD-2, KD-3, KD-4, KD-12 and KD-8 was from the first reservoir of Pliocene limestones, whereas the other wells (KD-6, KD-7, KD-9, KD-13, KD-14, KD-15 and KD-16) crossed marls and sandstones instead of limestones. Production was, therefore, impossible in these wells, and the marls and sandstones, together with other Pliocene deposits, form the cap rock. The maximum temperature recorded in the first reservoir was 198°C in KD-l well. The average temperature is about 170°C for this reservoir. The thickness of the reservoir rock varies between 100- 250 m.

The second reservoir: The alternations of marble-quartzite-schists of the İğdecik Formation in the Menderes metamorphic massif represent the second reservoir. Compared with the first reservoir, it has a relatively high secondary porosity and permeability. Furthermore, it has a lateral continuity over a very large area. As this reservoir lies at greater depths, it has higher temperatures. A temperature of 212°C was recorded at well bottom in KD-16. KD-6, KD-7, KD-9, KD-13, KD-14, KD-15, KD-16 and KD-111 wells have reached the second reservoir. Its thickness varies between 100- 300 m. Possibility of a third reservoir: Exploration of the first reservoir in Kızıldere geothermal field revealed that some parts did not have the requisite characteristics of a reservoir, yet a second reservoir was detected and explored. Its average temperature is 212°C while only 170°C in the first reservoir. According to geological data, thick and impermeable micaschists underlie the alternation of marble- quartzite - schist that forms the second reservoir. Gneiss and quartzites lie beneath the micaschists according to the general sequence, indicating that the transition zone could form a suitable reservoir formation. Furthermore, the dam site investigations of the D.S.I. (State Hydraulic Works) in the same area revealed that some parts of the basement gneiss (particularly the quartzitic gneiss), which are in fact composed of various gneiss, are permeable and could act as a reservoir, judging by the results of water permeability tests. The Na-K-Ca and SiO2 geothermometers indicate a temperature of 250- 260°C for this third hypothetical reservoir in the Kızıldere field. Further studies will be conducted to explore this third reservoir.” ENEL et.al.(1988) made following conclusions 20 years ago.

Şimşek(1985) considers the water circulation as given at Fig.55.

Figure.55: Cold and Thermal Water Circulatın According to Şimşek(1985)

VIII. RESOURCE ASSESMENT Serpen, et.al., had estimated geothermal potential of the Sarayköy geothermal field in 2000 (Serpen, et.al., 2000). According to their data expected values of accessible geothermal resource base for individual field of Sarayköy anomalie was 4.24 (1018J) (Expected Accessible Geothermal Energy, 1018J). Geological and geophysical information can provide a reliable categorization of the reservoir. First reservoir of the Field, Sazak Limestone reservoir can be taken as 200 m thick at 8 km2 area. The optimal temperature of this reservoir can be taken as 140°C. There must be a second reservoir medium in Metamorphic Basement rocks at deeper levels at least 4 km2 area and with minimum 200 m thickness. Temperature at this second reservoir are being predicted as 180°C. Total 2 km2 area between the depths of 400-1500 m along fault zones may provide a 170°C Metamorphic rock reservoir medium. A power potential estimation can be done by taking these data as minimum. Results are, 2,5 MW(e) for 8 km2 and 0,2 km thick, 140°C First Reservoir; 2,5 MW(e) for 4 km2 and 0,2 km thick, 180°C Second Reservoir; 5,5 MW(e) for 2 km2 and 1 km thick fault zone reservoir with 170°C and total capacity as 10,5 MW(e). This must be taken as minimum value.

IX. RESULTS Sarayköy Geothermal Field has been investigated extensively and in detail up to that time. Up to 125°C well bottom temperatures were measured. There must be at least two reservoir layers, one at Sazak Limestone’s and one at Metamorphic Basement. Geothermal system is belonged to the Miocene and recent fault zones. Extensive resistivity anomalies have been explored at this Field. Capacity of this Geothermal Field was estimated as minimum 10,5 MWe according to the available information. New exploration wells can be done especially at NW of this area. Respectfully Submitted by

Tahir Öngür Geologist

REFERENCES Akkuş, İ., Akıllı, H., Ceyhan, S., Dilemre, A. and Tekin, Z., 2005, Türkiye Jeotermal Kaynakları Envanteri, MTA Publ., in Turkish Aydan, Ö., Kumsar, H. and Tano, H., 2005, Multiparameter Changes in the Earth's Crust and Their Relation to Earthquakes in Denizli Region of Turkey, Proc. of WGC 2005, Antalya Bayrak, M., Serpen, U. and İlkışık, O.M., 2009, Electrıcal Resıstıvıty Image Of The Kızıldere Geothermal System Inferred From Magnetotelluric Data, Proc. of 34th Workshop on Geothermal Reservoir Engineering, Stanford University, Stanford, California Candan, O., Dora, Ö.O., Kun, N., Akal, N. ve Koralay, E., 1992, Aydın Dağları (Menderes Masifi) güney kesimindeki allokton metamorfik birimler, TPJD dergisi, C.4, no.1, syf.93-110 Catlos, E.J., 2002, In Situ Timing Constraints from the Menderes Masif, Western Turkey, http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_39303.htm Çağlar, K.Ö., 1948, Türkiye Maden Suları ve Kaplıcaları, c.2, MTA Yayını, in Turkish Çemen, İ., 2002, Extensional Tectonics in Southern Basins and Ranges, USA and in Western Turkey : A Review of Similarities, Differences and Problems, http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_39303.htm  Çetiner, H.L., 1999, The Hydrogeological Study of the Kızıldere (Denizli) Geothermal Field for Reinjection Purposes, PhD Thesis, DEU, unpublished Demirören, M., 1969, Denizli-Sarayköy Jeotermik Enerji Aramaları Kızıldere-Tekkehamam ve Karakova Jeotermal Gradyent Etüdleri Rapor(I), unpublished MTA report, nu. 4141, in Turkish Demirtaş, R., Erkmen, C. and Yaman, M., 2001, Denizli ve yakın civarının deprem üreten diri faylar ve Gökpınar sulama barajının depremsellik açısından incelenmesi, Dora, O.Ö., Candan, O., Dürr, St. and Oberhanslı, R., 1995, New Evidence on the Geotectonic Evolution of the Menderes Masif, Proc. of International Earth Sciences Colloqium on the Aegean Region, pp. 53-72, İzmir Emre, T. and Sözbilir, H., 1995, Field Evidence for Metamorphic Core Complex Detachment Faulting and Accomodation Faults in the Gediz and Büyük Menderes Grabens, Western Anatolia, Proc. of International Earth Sciences Colloquiuon the Aegean Region, pp. 53-72, İzmir Emre, T. and Sözbilir, H., 1995, Field Evidence for Metamorphic Core Complex, Detachment Faulting and Accomodation Faults in the Gediz and Büyük Menderes Grabens, Western Anatolia, Proc. of International Earth Sciences Colloquiuon the Aegean Region ENEL, Aquater and Geotermica Italiana, 1988, Optimization and Development of the Kızıldere Geothermal Field, Appendix 5: Integrative Prospectings Magnetotelluric Report, Erdoğan, B., 1992, Problem of core-mantle boundary of Menderes Massive, First International Symposium on Eastern Mediterranean Geology, Adana, Abs. 314-315 Erişen, B., 1971, Eşder, T., 1978, Büyük Menderes-Çürüksu Grabeni ve Yöredeki Jeotermal Sistemlerin Jeolojik Haritası, 1/100000, unpublished geological map, in Turkish Eyidoğan, H. And Jackson, J.A., 1985, A seismological study of normal faulting in the Demirci, Alaşehir and Gediz earthquakes of 1969-70 in Western Turkey : implications fort he nature and geometry of deformation in the continental crust, Jour. Of Geophys. Res., v81, p 569-607 Filiz, Ş., 1982, Ege Bölgesindeki Önemli Jeotermal Alanların O18, H2, H3, C13 izotopları ile İncelenmesi, Docentlik tezi, unpublished

Filiz, Ş., 1989, Isotopic Analyses of CO2 and Travertines in the Denizli Geothermal Province (West Anatolia), UN ECE Seminer on New Developğments in Geothermal Energy, Ankara Gökgöz, A., Geochemistry of the Kızıldere-Tekkehamam-Buldan-Pamukkale Geothermal Fields, Turkey, in: Georgsson, L. S. (ed.) Geothermal Training in Iceland, UNU Geothermal Training Programme, Reykjavik, Iceland, pp. 115-156 Güleç, N., 1988, Batı Türkiye’de Helyum-3 Dağılımı, MTA Bull., n.108, pp. 98-105 Gürgey, K., Simoneit, B.R.T., Karamanderesi, İ.H. and Varol, B., 2005, Organic Geochemistry of Hydrothermal Petroleum in the Menderes-Gediz Graben System, Denizli-Sarayköy, Western Turkey: Preliminary Results, Proc. of WGC 2005, Antalya Hetzel, R., Passchier, C.W., Ring, U., and Dora, O.Ö., 1995, Bivergent extension in orogenic belts: The Menderes Massive (southwestern Turkey), Geology, v.23, no.5, 455-458 Hetzel,R. and Reischman,T.,1996,  Intrusion age of Pan-African Augen Gneisses in the southern Menderes Massif and the age of cooling after alpine ductile extensional deformation.Geol. Mag.133,562 –572. Karamanderesi, İ.H. and Helvacı, C., 2003, Geology and Hydrothermal Alteration of the Aydın-Salavatlı Geothermal Field, Western Anatolia, Turkey, Turkish Journal of Earth Sciences, v.12, pp.175-198 Karamanderesi, İ.H. and Ölçenoğlu, K., 2005, Geology of the Denizli Sarayköy (Gerali) Geothermal Field, Western Anatolia, Turkey, Proc. Of WGC 2005, Antalya Karamanderesi, İ.H., 2002, Kadir Başoğlan Gerenlik Kaplıcaları Denizli Sarayköy Tırkaz Köyü Kokar Hamam Mevkii Üzerindeki Tesisler Sıcak Su Kuyusu (KB-1) ve Kokar Hamam Kaynakları Teknik Raporu, unpublished report Karamanderesi, İ.H., 1997, Aydın-Salavatlı Geothermal Fieldının Jeolojisi ve Hidrotermal Alterasyon Süreçleri, PhD Tezi, Dokuz Eylül Üniversitesi oğal ve Uygulamalı Bilimler Mezuniyet Sonrası Okulu, İzmir Kastelli, M., 1972, Denizli-Kızıldere Tekkehamam Kaplıcası Civarının Jeolojik Etüdü ve Jeotermal Enerji Olanakları, MTA Rap. 5744 Kaymakçı, N., 2005, Kinematic development and paleostress analysis of the Denizli Basin (Western Turkey): implications of spatial variation of relative paleostress magnitudes and orientations, Journ. Of Asian Earth Sci., 27, 207-222 Namoğlu, C., 1997, Geological and Geochemical Evaluation of the Geothermal Areas in Western Anatolia, PhD Thesis, METU, Ankara, 244 p. Okay, A., 1989, Denizli’nin Güneyinde Menderes Masifi ve Likya Naplarının Jeolojisi, MTA Derg., 109, 45-58 Okay, A.I., 2002, When and why did the Extension Start in the Aegean?, http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_39303.htm  Öngür, 1971, Denizli-Babadağ çevresine ilişkin jeoloji etüt ve jeotermik enerji olanakları hakkında rapor, MTA Rap. 4689, unpublished rep. Özgüler, M.E., Turgay, M.I. and Şahin, H., 1983, Geophysıcal Investıgatıons In Denizli Geothermal Fıelds, Turkey, MTA Bull 99-100, 129-141 Özgüner, A.M., Bulut, F. and Erduran, Y., 1975, Hydrothermal Sulphur Occurences of Denizli-Tekke Hamam Area, MTA Bull., v. , n., , pp 160-181 Özgür, N., 2002. Geochemical signature of the Kızıldere geothermal field, Western Anatolia, Turkey. International Geology Review 44:153-163 Özgür, N., 2003, Active Geothermal Systems in the Rift Zone of the Büyük Menderes, Western Anatolia, Turkey, proc. of European Geothermal Conference, Szeged, Hungary Özgür, N., Yaman, D, Wolf, W and Stichler, W., 2005, High boron contents of the Kızıldere geothermal waters, Turkey, WRI-11, Pisa Italy Sarı, C. ve Şalk, M., 1995, Estimation of the Thickness of the Sediments in the Aegean Grabens by 2D and 3D Analysis of the Gravity Anomalies, Proc. of International Earth

Sciences Colloquiuon the Aegean Region, pp. 255-269, İzmir Sarı, C. ve Şalk, M., 1995, Estimation of the Thickness of the Sediments in the Aegean Grabens by 2D and 3D Analysis of the Gravity Anomalies, Proc. of International Earth Sciences Colloquiuon the Aegean Region, pp. 255-269, İzmir Satır,M. and Friedrischsen,H.,1986.The origin and evolution of the Menderes Massif, western Turkey: rubidium/strontium and oxygen isotope study.Geol.Rund.75,703 –714. Sclater, J.G., Parsons, B. and Japuart, C., 1981, Oceans and contynents : similarities and differences in the mechansim of heat loss, J. Geophys. Res., 86, B12, 11535-11552 Serpen, U., Aksoy, N., Öngür, T. and Korkmaz, E.D., 2009, Geothermal energy in Turkey: 2008 update, Geothermics, in press Serpen, Ü. and Öngür, T., 2002, Critical Comment and Reply, Applied Geochemistry, Serpen, Ü., Yamanlar, S. and Karamanderesi, İ. H., 2000, Estimation of geothermal potential of B. Menderes region in Turkey. World Geothermal Energy Congress, 2000. Japan. pp:2205-2210. Seyitoğlu, G., 2002, Extensional Tectonics and Related Basin Development in Western Turkey, http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_39303.htm Sülün, S., Kaya, C. ve Duvarcı, E., 1985. Rejyonal jeoelektrik haritaları Denizli-Sarayköy Güney Sahası Rezistivite etüdü, MTA rap. 7653 Şen, Ş., 2002, Magnetostratigraphy and Vertical Rotational Tectonics in the Early-Middle Miocene Deposits of Alaşehir and Büyük Menderes Grabens, Western Turkey, http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_39303.htm Şimşek, Ş., 1982, Geology and Geothertmal REnergy Possibilities of the Denizli-Denizli-Sarayköy-Buldan Area, PhD Thesis, İstanbul Un. Şimşek, Ş., 1984, Denizli, Kızıldere-Tekkehamam Tosunlar-Buldan-Yenice Alanının Jeolojisi ve Jeotermal Enerji Olanakları, unpublished MTA report, 7846, in Turkish Şimşek, Ş., 1985a. Geothermal model of Denizli-Sarayköy-Buldan area. Geothermics, 14-2/3, 393-417. Şimşek, Ş., 1985b. Present Status and Future Development of the Denizli-Kizildere Geothermal Field of Turkey, International symposium on Geothermal Energy, pp.203-215 Hawaii Şimşek, Ş., 2003, Hydrogeological and Isotopic Survey of Geothermal Fields in the Büyükmenderes Graben, Turkey, Geothermics 32, 669-678 Taner, G., 1974a, Denizli Bölgesi Neojen’inin Paleontolojik ve Stratigrafik Etüdü-I, MTA Derg., 82, 89-126 Taner, G., 1974b, Denizli Bölgesi Neojen’inin Paleontolojik ve Stratigrafik Etüdü-II, MTA Derg., 83, 145-177 Taner, G., 1975, Denizli Bölgesi Neojen’inin Paleontolojik ve Stratigrafik Etüdü-III, MTA Derg. 85, 45-66 Tezcan, A. K., 1967, Denizli-Sarayköy Jeotermik Enerji Araştırmaları Gravite ve Rezistivite Etüdleri Raporu, unpublished MTA report, 3896, in Turkish Uysallı, H.,1967, Tekke-Kızıldere (Denizli-Sarayköy) sıcak su sahalarının jeolojik etüdü ve jeotermik enerji imkanları. M.T.A. Rap. no: 3874 (Yayınlanmamış), Ankara. Vengosh, A., Helvacı, C., and Karamanderesi, İ.H, 2002, Geochemical constraints fort he origin of thermal waters from western Turkey, Applied Geochemistry, v. 17, pp.163-183 Westaway, R., 1993, Neogene evolution of the Denizli region of western Turkey. Journal of Structural Geology, 15, 37-53. Wiersberg, T., Süer, S. Gülec, N. and Erzinger, J., 2009, Geochemical monitoring and noble gas characterization of the eastern segment of the Büyük Menderes Graben (Turkey), Geophysical Research Abstracts, Vol. 11, EGU2009-6871 Yalçınlar, İ., 1964, Babadağ Kaledonien Masifi ve Antrakolitik Örtüleri, MTA Dertg.

Yeltekin, K. ve Erkan, B., 2000, Kızıldere Jeotermal Sahasında Reenjeksiyon Amaçlı Delinen TH-2 ve R-1 Kuyularında Yapılan Test Çalışmaları, Cumhuriyetin 75. Yıldönümü Yerbilimleri ve Madencilik Kongresi Bildiriler Kitabı, v.II, pp.411-417, MTA Publication Yıldırım, N. and Güner, İ.N., 2005, Geochemical Properties and Determination of Turnover Time by Using 14C Isotope in Kızıldere and Tekkehamam Geothermal Field of Turkey, Proc. of WGC 2005, Antalya Yıldırım, N., 2008, Tekkehamam Jeotermal Alanı KG-1 Kuyusu İnhibitör Testleri, unpublished report Yıldırım, N., Demirel, Z. and Doğan, A.U., 1997, Kızıldere-Tekkehamam Geothermal Field, GEOENV 97, İstanbul Yılmaz, Y., 2002, Tectonic Evolution of Western Anatolian Extensional Province During the Neogene and Quaternary, http://gsa.confex.com/gsa/2002AM/finalprogram/abstract_39303.htm Yılmaz,Y., Genc,Ş., C., Gürer,F., Bozcu,M.,Yılmaz,K., Karacık,Z., Altunkaynak,Ş. and Elmas,A., 2000, When did Western Anatolian grabens begin to develop? In: Bozkurt, E., Winchester,J.A., Piper,J.D.A.(Eds.), Tectonics and Magmatism in Turkey and the Surrounding Area.Geol.Soc., London,Spec.Publ.,pp.353 –384.b