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Geology, Occurrence, and Genesis of Eskişehir Sepiolites, Turkey

Published online by Cambridge University Press:  28 February 2024

Ömer Içik Ece  and
Fazli Çoban
Ömer Içik Ece
Affiliation:
Istanbul Technical University, Faculty of Mines Mineralogy-Petrography Division, Maslak 80626 Istanbul, Turkey
Fazli Çoban
Affiliation:
Istanbul Technical University, Faculty of Mines Mineralogy-Petrography Division, Maslak 80626 Istanbul, Turkey
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Abstract

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The occurrences of sepiolite beds and nodules in alkaline and saline Miocene Eskisehir lake deposits provide unique examples of ancient lacustrine environments. Stockwork-type magnesite deposits, which were formed very close to the Miocene lake, served as parent rocks for sepiolite nodules (meerschaum). The Miocene succession consists of calcareous clay, clayey carbonate, dolomite, a gypsum-bearing calcareous clay series, siliceous tuffs, sepiolite beds, sepiolite-bearing dolomite, and basal conglomerates of ultramafic rocks. Sepiolite beds were deposited by direct precipitation from Si-supersaturated lake water under alkaline and saline conditions. They are underlain by a gypsum series. Organic matter-rich sepiolites suggest the presence of water stratification with anoxic bottom waters, which developed due to high sulphate input at the base from the ascending hydrothermal solutions along the fracture systems with extensive fresh water input near to the surface. Sepiolite nodules resulted from diagenetic replacement of magnesite pebbles at shallow burial under alkaline conditions in the vicinity of paleo-shorelines. Sepiolite beds were deposited in three ways: 1) black (up to 2.8 wt. % TOC) sepiolite beds rich in organic matter accumulated in an anaerobic paleoenvironment; 2) brown (about 0.5 wt. % TOC) sepiolite beds poor in organic matter, containing minor amounts of white, 2–6 mm long, discontinuous, and very soft dolomite laminae formed in a dysaerobic paleoenvironment; and 3) white dolomitic sepiolite beds in which dolomite content is about 20–40% in an aerobic paleoenvironment.

Cyclic dolomite and gypsum series indicate hypersaline-evaporative paleoenvironments with rapid changes in lake water chemistry. These cyclic evaporatic conditions are also related to cyclic changes in water depth. Based on X-ray powder diffraction data, except degree of crystallinity, no mineralogic difference was found between sepiolite in beds and nodules. SEM studies revealed fibers about 0.2 µm wide and up to 30 µm long in sepiolite beds; crystals less than 5 µm long with bent tips; and a more compacted appearance in sepiolite nodules.

Keywords

EnvironmentLacustrineMagnesiteSepioliteTurkey
Type
Research Article
Information
Clays and Clay Minerals , Volume 42 , Issue 1 , February 1994 , pp. 81 - 92
Copyright
Copyright © 1994, Clay Minerals Society

References

Abtahi, A. l.. 1977 () Effect of saline and alkaline ground water on soil genesis in semi-arid Southern Iran: Soil Sci. Amer. J. 41, 583–588.CrossRefGoogle Scholar
Akinci, Ö., (1967) Eskisehir I24-c1 Paftasinin Jeolojisi ve Tabakali Lütetasi Zuhurlari: M.T.A. Dergisi. Bull. of Min. Res. Exp. Inst. of Turkey 67, 82–97.Google Scholar
Fleischer, P., (1972) Sepiolite associated with Miocene diatomite, Santa Cruz basin, California: Amer. Mineral. 57, 903–913.Google Scholar
Folk, R. L., and Siedlecka, A., (1974) The “schizohaline” environment: Its sedimentary and diagenetic fabrics as exemplified by late paleozoic rocks of Bear Island, Svalbard: Sedimentary Geol. 11, 1–15.CrossRefGoogle Scholar
Folk, R. L., and Land, L. S., (1975) Mg/Ca ratios and salinity: Two controls over crystallization of dolomite: Bull. Amer. Assoc. Petrol. Geol. 59, 60–68.Google Scholar
Galan, E., and Ferrero, A., (1982) Palygorskite-Sepiolite Clays of Lebrija, Southern Spain: Clays & Clay Minerals 30, 191–199.CrossRefGoogle Scholar
Gibbs, R. J., (1965) Error due to segregation in quantitative clay mineral X-ray diffraction mounting techniques: Amer. Mineral. 50, 741–751.Google Scholar
Gibbs, R. L., (1968) Clay mineral mounting techniques for X-ray diffraction analysis: A discussion: J. Sediment. Petrol. 38, 242–244.CrossRefGoogle Scholar
Hewett, D. F., (1956) Geology and mineral resources of the Wanpal Quadrangle, California and Nevada: U.S. Geol. Survey Prof. Paper 275, 143–144.Google Scholar
Jackson, M. L., (1975) Soil Chemical Analysis—Advanced Course: 2nd ed., published by the author, Madison, Wisconsin, 895 pp.Google Scholar
Jones, B. F., and Galan, E., (1988) Sepiolite and palygorskite: in Hydrous Phyllosilicates (Exclusive of Micas), Bailey, S. W., ed., Reviews in Mineralogy, Mineralogical Society of America 19, 631–674.CrossRefGoogle Scholar
Krauskopf, K. B., (1956) Dissolution and precipitation of silica at low temperatures: Geochim. Cosmochim. Acta 10, 1–26.CrossRefGoogle Scholar
Kulaksiz, S., (1981) Sivrihisar Kuzey-Bati Yöresinin Jeolojisi: Hacettepe Univ. Yerbilimleri 8, 103–124.Google Scholar
Longman, M. W., (1980) Carbonate diagenetic textures from nearshore diagenetic environments: Bull. Am. Assoc. Petrol. Geol. 64, 461–487.Google Scholar
Otsuka, R., Mariko, T., and Sakamoto, T., (1973) Mineralogische Eigenschaften vom Meerschaum von Eskisehir, Turkei: in Memoirs of the School of Science & Engineering, Waseda Univ. Japan 37, 43–52.Google Scholar
Post, J. L., (1978) Sepiolite deposits of the Las Vagas, Nevada, area: Clays & Clay Minerals 26, 58–64.CrossRefGoogle Scholar
Shadfan, H., Mashhady, A. S., Dixon, J. B., and Hussen, A. A., (1985) Palygorskite from tertiary formation of Eastern Saudi Arabia: Clays & Clay Minerals 33, 451–457.CrossRefGoogle Scholar
Singer, A., (1984) Pedogenic palygorskite in the arid environment: in Palygorskite-Sepiolite: Occurrences, Genesis and Uses, Singer, A., and Galan, E., eds., Elsevier, Amsterdam , 169–175.Google Scholar
Velde, B., (1985) Clay Minerals: A Physico-Chemical Exploration of Their Occurrence: Elsevier, Amsterdam , 225–256.Google Scholar
Wey, B., and Siffert, B., (1961) Reaction de la silice monomoleculaire en solution avec les ions Al, Mg. Genese et Synthese des Argiles: Colloq. Int. C.N.R.S. 105, 11–23.Google Scholar
Weaver, C. E., and Beck, K. C., (1977) Miocene of the S.E. United States: A model for chemical sedimentation in a peri-marine environment: Sedimentary Geol. 17, 201–225.CrossRefGoogle Scholar
Williams, L. A., and Crerar, D. A., (1985) Silica diagenesis: II. general mechanisms: J. Sediment. Petrol. 55, 312–321.Google Scholar
Wollast, R., Mackenzie, F. T., and Bricker, O., (1968) Experimental precipitation and genesis of sepiolite at earth-surface conditions: Amer. Mineral. 53, 1645–1662.Google Scholar
Yeniyol, M., and Öztunali, Ö., (1985) Yunak Sepiolitinin Mineralojisi ve Olusumu. II. Ulusal Kil Sempozyumu Bildiriler: Hacettepe Univ., Ankara, 24–27.Google Scholar
Yeniyol, M., (1986) Vein-like sepiolite occurrence as a replacement of magnesite in Konya, Turkey: Clays & Clay Minerals 34, 353–356.CrossRefGoogle Scholar
Yariv, S., and Cross, H., (1979) Geochemistry of Colloid Systems: Springer-Verlag, Berlin, 405 pp.CrossRefGoogle Scholar