DISTRIBUTION AND GENESIS OF NEOFORMED MINERALS IN KOYUNAĞILI (MIHALIÇÇIK-ESKİŞEHİR) AREA

- The study area is located at the Southwest of Koyunağılı village situated in the south margin of the BeypazarıQayirhan basin which is in the Middle Sakarya Massif. The Neogene units in the investigated area are Çoraklar, Hırka, Karadoruk, Akpınar, Bozçayır, Acısu and Kırmızıtepe Formations. The mineralogic features of the clay minerals and tha host rock samples were studied by means of petrographic, XRD, DTA-TG, SEM-EDX and IR Spectra techniques. Various effects of pH values of the environment related to evaporation and feeding of the basin from several areas, cause the formation of different mineral paragenesis. The main mineral paragenesis are; loughlinite + analcime + calcite + dolomite + feldspar, sepiolite + analcime + dolomite + illite, sepiolite + analcime + dolomite + opal-CT + feldspar, montmorillonite + analcime + dolomit + illite + feldspar + quartz + opal-CT, montmorillonite + analcime + calcite + felspar + illite and montmorillonite + dolomite + calcite + analcime + quartz + Feldspar. Montmorillonite is formed at the margin of the basin, derived from freswater and detritic materials which contain Al and Mg. Aluminum ions are generally dominant in the shallow part of the basin facies of the Bozçayır and Acısu Formations. In the Akpınar Formation, sepiolite is formed at a non-acidic environment, which is rich in Mg and Si, but poor in Al. At the center of the area (around Ocak), loughlinite is formed in a way similar to that of sepiolite by combining of Na, originated from the alteration of tuff, to the Si and Mg. As a result of the alteration, especially after the formation of montmorillonite the proportion of (Na+K)/H increases and finally analcime and feldspar are formed. At the south of the area magnesite is formed at the bottom part of the Hırka Formation, due to the high Mg and pH and low Si values. To the north, some dolomite, depending on the decreasing of Mg content, is observed. At the north, dolomite and calcite are formed interbededly, due to changes in the pH conditions controlled by evaporation and freshwater participations. Sepiolite, loughlinite, analcime, feldspar, opal-CT and a small amount of quartz are formed authigenically, in and around the altered glass pores as a result of alteration of volcanic glasses. 
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  • ATAMAN, G., 1976. Türkiye'de yeni bir analsim olu- şuğu ve zeolitli serilerle plaka tektoniği ara- sında muhtemel ilişkiler. H.Ü., Yerbilimleri (2), 9-23, Ankara.
  • CAILLERE, S., 1951, Sepiolite. in: G. W. Brindley, X-ray identification and structures of clay minerals: Mineral Soc., London, 224-233.
  • CAMPBELL, A. S. and FYFE, W. S., 1965, Analcime-albite equilibria: American Jour. Sci. 263, 807-816.
  • ECHLE, W., 1967, Loughlinite (Na-sepiolith) und Analcim in Neogenen sedimenten Anatoliens: Contr. Mineral. Petrol. 14, 86-101.
  • --, 1974, Zur mineralogie und petrogeneses jungtertiarer tuffitischer sedimente im Neogen-Backen nördlich Mihalıççık (Westanatolien, Turkei): N. Jb. Miner. Abh. 121,43-84.
  • — , 1978, The transformations sepiolite <=>loughlinite experiments and field observa- tions: N. Jb. Miner. Abh. 133 (3), 303-321.
  • EUGSTER, H. P., 1970, Chemistry and origin of the brines of lake Magada, Kenya: Mineralog Soc. America Spec. Pub. 3, 215-235.
  • FONTES, J. C.; FRITZ P.; GAUTHİER, J. and KUL- BİCKİ, G.; 1967, Mineraux argileux, elements traces et compositions isotopiques (18O/16O- et13C/12C) dans les formations gypsiferes de l'Eocene Superieur et dans l'Oligocene de Cormeilles-en Parisis: Bull. Cent. Rech. Pau.- SNPA, 1,315-366.
  • GALAN, E. and FERROS, A., 1982, Playgorskite- sepiolite clays bf Lebrija. Southern Spain: Clays and Clay Minerals, 30, 191-199.
  • GÜNDOĞDU, M. N., TENEKEÇİ, O.; ÖNDER, R; DÜNDAR, A. and KAYAKIRAN, S., 1985 Beypazarı trona yatağının kil mineralojisi, on çalışma sonuçları: II. Ulusal Kil Sempozyumu Bildirileri, H. Ü. (Eds: M. Niyazi Gündoğdu ve Hüsnü Aksoy), 141-153, Ankara.
  • HARDİE, L. A.; SMOOTH, J. P. and EUGESTER, H. P., 1978, Saline lakes and their deposits. A sedimentological approach: In modern and ancient lake sediments: A. Matter, M, E Tucker (Eds.) Blackwell Sci. Publ. Oxford, 7- 24.
  • HAST, N., 1956, Low-tempreture synthesis of sepi- olite: Arkiv Mineral Geol., 9, 313-360.
  • HAY, R. L., 1963, Stratigraphic and zeolitic diagen- esis of the John Day Formation of Oregon: California University. Pubs. Geol. Sci., 42, 199-262.
  • , 1965, Pattern of silicate authigenesis in the Green River Formation of Wyoming (abstr.): l. Soc. Amer. Spec. Pap. 82, 88 s.
  • , 1966, Zeolites and zeolotic reactions in sedimentary rocks: Geol. Soc. Amer. Spec. Paper, 85, 130 s.
  • --, 1970, Silicate reactions in three lithofacies of a semi-arid basin, Olduvai George Tanznia: Mineral. Soc. Amer. Spec. Paper, 3, 237-255.
  • HELVACI, C.; İNCİ, U.; YAĞMURLU, F. and YILMAZ, H., 1989, Geologic and Neogene trona depo- sit of the Beypazarı region: Doğa Bilim Dergi- si, 13(2), 245-256.
  • --, YILMAZ, H and İNCİ, U., 1988, Beypazarı (Ankara) yöresi Neojen tortularının kil miner- alleri ve bunların dikey ve yanal dağılımı: Jeoloji Mühendisliği, no. 32-33, 33-42.
  • İİJİMA, A. and HAY, R. L, 1968, Analcime compo- sition in the Green River Formation of Wyoming: American Mineralogist, 53 (1-2), 184-200.
  • İSPHORDİNG, W. C., 1973, Discussion of the occurrence and origin of sedimentary palygirskite-sepiolite deposits: Clays and Clay Minerals, 21, 391-401.
  • JONES, B, F., 1986, Clay mineral diagenesis in lacus- trine sediments. In Diagenesis Workshop: U. S. Geol. Survey Bull., 1578, 18s.
  • KADİR, S. and BAŞ, H., 1995, Koyunağılı (Mihalıççık-Eskişehir) sepiyolit oluşum- larının mineralojisi, VII. Ulusal Kil Sempozyumu, Kill 95 Bildiriler Kitabı (Eds: Mehmet Şener, Ferda Öner ve Erdal Koşun), 19-31, Ankara.
  • KAYAKIRAN, S. and ÇELİK, E., 1986, Beypazarı trona (doğal soda) yatağının maden jeolojisi raporu: M.T.A. report No. 8079, Ankara.
  • MİLTON, C. and EUGSTER, H. P., 1959, Mineral assemblages of the Green River Formation. In P. H. Abelson, Ed., Research in Geochemistry, Vol. 1, John Wiley and Sons, New York, 118-150.
  • MİLLOT, G., 1964, Geologie des Argiles. Masson and Cie, Paris, 510 s.
  • MOİOLA, R. J., 1970, Authigenic zeolites and K- feldspars in the Esmeralda Formation, Nevada: American Mineralogist, 55, 1681- 1691.
  • MUMPTON, F. A. and ROY, R., 1958, New data on sepiolite and attapulgite: Clays and Clay minerals 5, 136-143. Nat. Acad. Sci. Natl. Res. Con. Rub. 566 s.
  • SHEPPARD, R. A., and GUDE, A. J., 3rd, 1968, Distribution and genesis of authigenic sili- cate minerals in tuffs of Pleistocene lake Tacopa, Inyo Country, California: U. S. Geol. Survey Prof. Paper, 597, 38 s.
  • , , 1969, Diegenesis of tuffs in the Barstow formation, Mud Hills, San Sarnardino Country, California: U. S. Geol. Survey Prof, Paper, 634, 35 s.
  • , , 1973, Zeolites and associated authigenic silicate minerals in tuffaceous rocks of the Big Sandy Formation, Mohave Country. Arizona: U. S. Geol. Survey Prof. Paper, 830, 36 s.
  • SİNGER, A. and GALAN, E., 1984, Palygorskite- Sepiyolite Occurences, Genesis and Uses. Developments in Sedimentology, 352 s.
  • SİYAKO, F., 1982, Eskişehir-Mihalıççık-Koyunağılı linyit kömürü sahasının jeoloji raporu: M.T.A., Report No. 7111, Ankara.
  • , 1983, Beypazarı (Ankara) kömürlü Neojen havzası ve çevresinin jeoloji raporu. M. T. A., Report No., 7431, Ankara.
  • STARKEY, H. C. and BLACKMON, P. D., 1979, Clay mineralogy of Pleistocene lake Tacopa, Inyo County, California: Paligoskite- Sepiyolite Occurrence, Genesis and Uses, A. Singer and E. Galan (Ed.), 137-147. SURDAM, R.C. and PARKER, R.B., 1972, thigenic aluminosilicate minerals in the