Water Chemistry and Isotope Studies In Aksaray Geothermal Fields (Acıgöl-Ziga-Şahinkalesi), Central Anatolia, Turkey

Yıl 2009, Cilt: 138 Sayı: 138, 45 - 68, 01.07.2009

Musa Burçak

Öz

The basement in the study area is comprised of gneisses of Paleozoic Tamadaq formation, marbles of Bozcaldağ formation and Upper Cretaceous Baranadağ granitoid intrusion into the above-mentioned rocks. These units have unconformable relations with Lower Eocene Cayraz formation and sedimentary rocks of Upper Eocene - Lower Miocene Mezgit group. All these units are unconformably overlain by Middle Miocene- Quaternary tuffs, ignimbrites with sedimentary intercalations and rocks of Cappadocia Volcanic belt represented by tuffites with sedimentary interbedding, basaltic lavas, volcanic ashes, pumice, dacitic-rhyodacitic lava domes. The study area contains Ziga and AClgöl (Narkoy) thermal fields which have a temperature of 44-65 °C from wells and hot springs. Hydrothermal alterations surrounding the geothermal area; young volcanic and tectonic activity, and the hot springs are the surface manifestation of the geothermal possibilities in the area. Reservoir rocks of the geothermal system are Paleozoic gneiss, schist and marbles. Cap rocks of the system in the study area are hydrothermally altered tuffs and ignimbrites. According to the classification of IAH (International Association of Hydrogeologists) standards while; all of the cold waters are Ca-Mg-HCO3 and CaHCO3 type in the region, the hot waters of the Acigöl field are classified as Ca-Na-HCO3-CI type and mineralized hot waters, the hot waters in Ziga field are classified as Na-CI-HCO3 type and B bearing mineralized hot waters, the hot water of Şahinkalesi field (from well) is classified as non-mineralized thermal water. Deuterium results suggest 1500-1600 m recharging elevation for hot springs and water chemistry and isotope studies imply that recharging area may extend up to the foothills of the Hasandaq. Tritium analyses have revealed that the hot water was recharged from precipitation before nuclear tests experienced before 1952 (I.e. older than 60 years). According to SiO2 - enthalpy mixing model, 155°C reservoir temperature and 65% cold water mix were calculated for AClgöl field. On the basis of chalcedony geothermometer, 114-160°C, 69-93 °C and 135°C and on the basis of quartz geothermometer 140-181 °C, 99-121 °C, and 159°C reservoir temperatures were calculated for Acıgöl, Ziga and Şahinkalesi geothermal fields, respectively.

Anahtar Kelimeler

Water, Chemistry, Isotope Studies

Water Chemistry and Isotope Studies In Aksaray Geothermal Fields (Acıgöl-Ziga-Şahinkalesi), Central Anatolia, Turkey

Öz

The basement in the study area is comprised of gneisses of Paleozoic Tamadaq formation, marbles of Bozcaldağ formation and Upper Cretaceous  Baranadağ granitoid intrusion into the above-mentioned rocks. These units have unconformable relations with Lower Eocene Cayraz formation and sedimentary rocks of Upper Eocene - Lower Miocene Mezgit group. All these units are unconformably overlain by Middle Miocene- Quaternary tuffs, ignimbrites with sedimentary intercalations and rocks of Cappadocia Volcanic belt represented by tuffites with sedimentary interbedding, basaltic lavas, volcanic ashes, pumice, dacitic-rhyodacitic lava domes. The study area contains Ziga and AClgöl (Narkoy) thermal fields which have a temperature of 44-65 °C from wells and hot springs. Hydrothermal alterations surrounding the geothermal area; young volcanic and tectonic activity, and the hot springs are the surface manifestation of the geothermal possibilities in the area. Reservoir rocks of the geothermal system are Paleozoic gneiss, schist and marbles. Cap rocks of the system in the study area are hydrothermally altered tuffs and ignimbrites. According  to the classification  of IAH (International  Association  of Hydrogeologists)  standards  while; all of the cold waters  are Ca-Mg-HCO3 and CaHCO3   type in the region, the hot waters of the  Acigöl field are classified  as Ca-Na-HCO3-CI   type and mineralized hot waters, the hot waters in Ziga field are classified  as Na-CI-HCO3   type and B bearing mineralized hot waters,  the hot water of Şahinkalesi  field  (from well) is classified  as non-mineralized  thermal  water. Deuterium  results suggest  1500-1600  m recharging elevation for hot springs and water chemistry and isotope studies imply that  recharging  area may extend  up to the foothills of the Hasandaq.  Tritium analyses have revealed that the hot water was recharged from  precipitation  before nuclear tests experienced before 1952 (I.e. older than 60 years). According to SiO2  - enthalpy mixing model, 155°C  reservoir temperature and 65% cold water mix were calculated for AClgöl field. On the basis of chalcedony geothermometer, 114-160°C, 69-93 °C and 135°C and on the basis of quartz geothermometer  140-181 °C, 99-121 °C, and 159°C  reservoir temperatures were calculated for Acıgöl, Ziga and Şahinkalesi geothermal fields, respectively.

Anahtar Kelimeler

Aksaray geothermal fields, hydrochemistry, geothermometer, mixing model, isotope

Kaynakça

• Afsin, M. and Bas, H. 1997. Bazi önemli soğuk ve sıcak su kaynaklarının hidrokimyasal ve izotopik incelemesi ve kökensel yorumu (Aksaray- Nigde arasi), TUBİTAK 195Y009 numaralı proje, 64 s (unpublished).
• Akdoğan, N. 1989. Aksaray (Nigde) Ihlara Vadisi jeotermal enerji aramaları gravite etudu Raporu: MTA Genel Müdürlüğü Rapor No: 10040, (unpublished), Ankara.
• Akdoğan, N., Burcak, M. and Yildırım, T 2002. Orta Anadolu Hasandağ volkanizrması kuzeyini jeoloji jeofizik verilerin korelasyonu ile jeotermal olanaklarına yeni bir bakis. Orta Anadolu jeoter- mal enerji ve cevre sempozyumu Bildiriler kitabı, s.45-57, N.Ll. Aksaray Müh. Fak. Jeo. ve Cevre Müh., Aksaray.
• Aydar, A., Gündogdu N., Bayhan,H., and Gourgaud, A. 1994. Kapadokya bölgesinin Kuvaterner vaşlı volkanizrnasmm volkanik-yapısal ve petrolojik incelemesi: TUBiTAK Yerbilimleri Dergisi, 3, 25-42.
• and Gourgaud, A. 1998. The geology of Mount Hasan strato-volcano, Central Anatolia, Turkey. Journal of Volcanology and Geothermal Research 85, 129-1 52.
• Ayhan, A.K. and Papak, i. 1988. Aksaray-Tasprnar- Altmhlsar-Cittlik Delihebil (Nigde) civarının jeolojisi: MTA Genel Müdürlüğü Report No:8315, (unpublished) Ankara, Turkey.
• Barka, A. 1992. The North Anatolian Fault Zone, Annal, Tectonica, Special Issue 6, 164-195. Batum, I. 1978a. Nevşehir qunevbatrsmdaki Göllüdag ve Acıgöl volkanitlerinin jeokimyast ve petrolojisi, Yerbilimleri, 4/1-2, 70-88.
• , 1978b, Nevşehir quneyoatrsmdaki Göllüdag ve Acigol yoresi volkanitlerinin jeolojisi ve petrolojisi: Yerbilimleri 4, 1-2, 50-69.
• Beekman, P. H. 1966. Aksaray, Gelveri, Cmarh bolgesinin jeoloji Raporu (Hasandan-Melendiz Dağı srrasrrun kuzeyi): MTA Genel Mudurlugu Report No: 5218, (unpublished), Ankara
• Bigazzi, G., Yegingil, Z., Ercan, T, Oddone, M. and Ozdoqan, M. 1993. Fission track dating obsidians of Central and Northern Anatolia. Bull. Volcanol. 55, 588-595.
• Burcak, M. 2006. Aksaray jeotermal sahalan (Acıgöl, Ziga, Şahinkalesi) jeotermal lSI kaynaklanrun arastmlrnasi ve jeotermal sistemlerin kav- ramsal modellemesi, Orta Anadolu Türkiye. Nigde Universitesi Fen Bilimleri Enst. Müd. Yuksek Lisans tezi. 85s.
• Burcak, M., Kaya, C. and Kılıç, A.R. 2004. Aksaray Bölgesi'nde (Orta Anadolu, Turkiye) ısı kaynagı ve jeotermal enerji potansiyeli araştırmaları TMMOB. 57. Türkiye Jeoloji Kurultayi Bildiri Ozleri Kitabi.
• , , _ and Akdogan, N. 2005. Exploration of the heat source and geothermal possibilities of the Aksaray region, Central Anatolia, Turkey. Proceedings World Geothermal Congress WGC 2005 Antalya Turki-ve- Exploration Session. 14. C.-Paper number: 2633. ISB-975-98332-0-4
• M., Hacrsalihoğlu, Ö., Kılıç , A.R. and Ozkan, H. 2007. Aksaray Ziga Acıgöl Şahinkalesi jeotermal sahaları jeoloji-jeofizik-jeokimya etut Report: MTA Genel Mudurlügü Report No: 10994, (unpublished), Ankara.
• Craig, H. 1961. isotopic variations in meteoric waters, Science, 133, 1833-1834.
• Dhont, D., Chorowitz, J., Yurur, T, Froger, J. L. Köse, O. and Gundoqdu, N. 1998. Emplacement of volcanic vents and geodynamics of Central Anatolia, Turkey. Journal of Vole. And Geoth. Research 85, 33-54.
• Druitt, T. H., Brenchley, P.J., Gökten, Y.E. and Francaviglia, V. 1995. Late Quaternary rhyolitic, eruptions from Acrqol complex, central Turkey. Geol. Soc., London, 152,655-667.
• Ercan,T., FUjitani., T., Matsuda, J.I.,Tokel, S., Notsu, K., UI, T.,Can., B., Selvi, Y., Yrldmrn, T., Fi-~ek{:i, A., Olmez, E., and Akoasf), A. 1990. Hasandaq, Karacadaq Orta Anadolu dolayla- nndaki Senozoyik yasu volkanizmamn kbke- ni ve evrimi: Jeomorfoloji dergisi, 18, 39-54.
• , Tokel, S., Matsuda, J., UI, T.,Notsu, K. and Fujitani., 1. 1992. Hasandaq- Karacadaq (Orta Anadolu) Kuvaterner volkanizmasma iliskin yeni jeokimyasal, izotopik ve radyo- metrik veriler: T JK Bulteni, 7, 8-21.
• Fournier, R.O. 1977. Application of Water Chemistry to Geothermal Exploration and Reservoir Engineering. In L. Rybach and L J. P. Muffler (Eds.), Geothermal Systems: Principles and Case Histories (pp. 109-143). New York Wi- ley.
• Giggenbach, W. F 1988. Geothermal solid equilibrie. Derivation of Na-Na-Mg-Ca indicators: Geochemica at Cosmochimica Acta 52,2749- 2765.
• Göçmez, G. 1994. Aksaray sıcak ve mineralli su kaynaklarının hidrojeoloji incelemesi; S.U.Fen Bilimleri Enst. Doktora Tezi, 280s., Konya
• Gbncuoglu, M, C. 1992. Nigde masifinin jeolojisi: Orta Anadolu jeoloji sempozyumu, TJK yaymla- n, 16-19.
• Erler, A., Toprak, V.,Yahmz, K., Olgun, E. and Rojay, B. 1992. Orta Anadolu masifinin ban bolurnunun jeolojisi, bolum 2 Orta kesim: TPAO Report No: 3535, (unpublished) Ankara.
• IAH (International Association of Hydrogeologists) 1978. Hydrochemistry of mineralized waters Conference of Cieplice Spa (Poland): Proceedings. Warsaw Geologicallnstutute.
• Innocenti, F., Mazzuoli, R., Pasquare, G., Radicati, F. and Villari, L 1975. The Neogene Calc-alka- line Volcanism of Central Anatolia; Geochro- nological data on Kayseri-Niqde area: Geol. Mag., 112/4,349-360. Kara, i. 2007. Aksaray-Guzelyurt-Sahinkalesi SHK-l steak su sondap kuyu bitirme Raporu: MTA Genel Mudurlugu Report No:ll 004, (unpub- lished), Ankara.
• Kaya, C., and Tokgöz, T. 1991. Aksaray Ihlara sahasi jeotermal enerji ararnalan jeofizik yapay kay- nakh rnanyetotellurik CSMAT etudu: MTA Genel Mudurlugu Report No: 878, (unpublis- hed), Ankara.
• Kaynak, M. 1989. Nigde-Aksaray jeotermal enerji ara- rnalan jeofizik manyetik etudu Nisan, Jeofizik Report No:765.
• Keller, J. 1974. Quaternary maar Volcanism near Ka- rapmar in Central Anatolia: Bull. Volcan., 38/2, 378-396.
• Lahn (llhan), E. 1945. Anadolu'da Neojen ve Dordun- cu zaman volkanizmasi.Turk Cografya Dergi- si, 3. YII, saYI:7-8.
• Le Pennec, J.L., Bourdier, L.F, Temel, A., Camus, G. and Gourgaud, A. 1994. Neogene ignimbrites of the Nevsehir Plateau (Central Turkey): Stratigraphy, distribution and source constraints: Journal of Volcanology and Geothermal Research, 63, 59-87.
• Mc Kenzie. 1972. Active tectonics of the Mediterranean region. Geophys. Jour. Roy. Astr. Soc. 30, 109-185.
• Mc Kenzie, D.P. and Yılmaz, Y. 1991. Deformation and volcanism in Western Turkey and Ae- gean. Bull. Tech. Univ. Istanbul, 44, 345- 373.
• Oktu, G. and Kalkan, i. 1984. Nigde-Aksaray-Ziga kaphcasrnm hidrojeoloji incelemesi: MTA Genel MLidLirlugu Report No: 7505, (un- published), Ankara.
• Olrnez., E. and Gevrek, A.i. 1991. Aksaray-Sofular- 1(SFG 1) ve Sofular-2 (SFG2) ile Ziga-Beli- srrrna 1-2 (ZBG1 ve ZBG2) gradyan son- dajlan kuyu bitirme raporu: MTA Genel Mu- durlugu Report No: 9194, (unpublished), Ankara.
• Pasquare, G. 1966. Outlines of the Neogene and Quaternary Volcanism of Asia Minor: Ac- cad. Naz. dei Ling., 40,1077-1085.
• Pasquare, G. 1968. Geology of the Cenozoic Volca- nic area of Central Anatolia: Atti Delia Ac- cad. Nazio. Dei. Lincei,Memorie, ser. 8, 9/3, 55-204.
• Poli, S., Vezzoli, L. and Zanchi, A. 1988. Continental arc volcanism and tectonic set- ting in Central Anatolia. Tectonophysics, 146,217-230.
• Saym, M. and Eyupoglu, S.O. 2005. Turkiye'deld ya- gl~larm kararh izotop iceriklerini kullanarak yerel meteorik doqrulann belirlenmesi. II. Ulusal Hidrolojide izotop Teknikleri Sem- pozyumu, s323-344. D.S.i. Gumuldur ? iz- mir.
• Schumacher, R., Keller, J. and Bayhan, H. 1990. Depositional characteristics of ignimbrites in Cappadocian, Central Anatolia Turkey. In MY Savascrn and A.H. Eronat (Editors), Proc. Int. Earth Sci. Congo On Aegean Regions, IESCA, 2, 435-449.
• Seymen, i. 1981. Kaman (Kırşehir) dolaymda Kırşehir Masifinin stratigrafi ve metamorfizrnası, TJK Bülteni, 24/2,7-17. Sur, b. 1972. Turkiye'nin ozellikle ic.,;Anadolu'nun gene;: volkanik alanlarrrun jeomorfolojisi: DTCF Yay, Sayı: 223.
• Şengor, A.M.C., Gorur, N. and Şaroglu, F. 1985. Strike-slip deformation, basin formation and sedimentation: Strike-slip faulting and related basin formation in zones of tectonic escape: Turkey as a case study. In: Biddle, K.T. and Christie-Blick, N. (eds), Strike-slip Faulting and Basin Formation. Society of Economic Paleontologists and Mineralogist, Special Publications 37, 227-264.
• Temel, A., GOndogdu, M. N., Gourgaud, A. and Le Pennec Jean-Luc. 1998. ignimbrites of Cappadocia (Central Anatolia, Turkey): petrology and geochemistry. Journal of. Volcanology and Geothermal Research 85, 447-471.
• Toprak, V. 1998. Vent distribution and its relation to regional tectonics, Cappadocian Volcanics, Turkey Jour. Volcanol. Geotherm. Res., 85, 55-68.
• 2000. Tuz Golu Fay Kuşağı Hasandağ kesiminin özellikleri. Haymana-Tuz Golu-Ulukışla basenleri uygulamalı calışma (Work- shop) Aksaray, TPJD ozel sayt 5, 71-84