Abstract
Occurrence and field relations of an extensive ignimbrite sheet near Afyon in Central Anatolia are described.
These rhyolitic ignimbrites are part of the important Neogene volcanic activity in Turkey and belong to the alignment of volcanic complexes along the inner border of the Taurian ranges.
In close stratigraphical connection and in the same tectonic position as the rhyolites there occurs an assemblage of high-potassic, intermediate to basic volcanic rocks (alkali trachytes, mela-trachytes, latites and leucite-bearing rocks).
Petrological and magmatological considerations led to the conclusion that the rhyolites and the potassic series, in spite of the close geological connection, are not related by processes of magmatic differentiation.
Arguments in favour of an anatectic origin of the rhyolitic melt are presented. The occurrence of garnet and allanite as accessory minerals and as inclusions in the salic minerals of the ignimbrite are interpreted as relictic witnesses of a sialic parent rock. However, the trace elements, especially high Rb connected with low Sr, Ba and Zr and K/Rb ratios below 100 give a pattern generally explained by strong fractionation processes.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Becker-Platen, J. D., 1970,Lithostratigraphische Untersuchungen im Känozoikum Südwest-Anatoliens. Beih. Geol. Jb.,97, 244 pp., Hannover.
Behring, D., 1971,The development of Neogene and Quaternary intramontane basins within the Pisidic lake district in S. Anatolia. Newsl. Stratigr.,1, p. 27–32, Leiden.
Dickinson, W. R. andHatherton, T., 1967,Andesitic volcanism and seismicity around the Pacific. Science,157, p. 801–803.
Ewart, A., Taylor, S. R. andCapp, A. C., 1968,Trace and minor element geochemistry of the rhyolitic volcanic rocks, Central North Island, New Zealand. Contr. Miner. and Petrol.,18, p. 76–104.
Green, T. H. andRingwood, A. E., 1968,Origin of garnet phenocrysts in calc-alkaline rocks. Contr. Miner and Petrol.,18, p. 163–174.
Ketin, I., 1966,Tectonic units of Anatolia (Asia Minor). MTA Bull.,66, p. 23–34.
McKenzie, D. P., 1970,Plate tectonics of the Mediterranean region. Nature,226, p. 239–243.
Ninkovich, D. andHays, J. D., (in press),Tectonic setting of Mediterranean volcanoes. Acta Intern. Scient. Congr. on the Volcano of Thera.
Parejas, E., 1943,Le substratum ancien du Taurus occidental au sud de Afyonkarahisar (Anatolie). C. R. Séances Soc. Phys. et Hist. Nat. Genève,60, p. 110–114.
Pasquare, G., 1968,Geology of the cenozoic volcanic area of Central Anatolia. Atti Ac. Naz. Licei, Mem.,IX, sez. II, p. 56–204.
Taylor, S. R., 1965,The application of trace element data to problems in petrology. Phys. Chem. Earth,6, p. 133–213.
————— andCapp, A. C., 1968,Leucogranites and rhyolites: Trace element evidence for fractional crystallisation and partial melting. Lithos,1, p. 179–186.
Westerfeld, J., 1957,Phases of Neogene and Quaternary volcanism in Asia Minor. Int. Geol. Congr. Sect. 1,1, p. 103–119, México.
Wijkerslooth, P. de, 1944,Über den jungen Vulkanismus am Innenrande des Taurus zwischen Afyon-Karahisar und Kayseri (Türkei). MTA Enst. Mecm.,2, p. 250–256.
Geological Map of Turkey, 1:500,000 SteetAnkara.
Author information
Authors and Affiliations
Additional information
Paper presented to the Simposium « Acid Volcanism », 15th IUGG General Assembly, Moscow, 1971.
Rights and permissions
About this article
Cite this article
Keller, J., Villari, L. Rhyolitic ignimbrites in the region of Afyon (Central Anatolia). Bull Volcanol 36, 342–358 (1972). https://doi.org/10.1007/BF02596876
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF02596876