Bahatlar volkanitlerinin (Emet-Kütahya) petrografisi ve jeokimyası

Öz

Batı Anadolu’da Eosen-Kuvaterner yaş aralığında volkanik kayaçlar yaygın olarak yüzlek vermektedir. Erken Miyosen volkanitleri Kütahya ve çevresinde andezit, dasit ve riyolitler şeklinde temsil edilmektedir. Bu çalışmada Emet Bor Havzası’nda yüzeyleyen riyolitlerden oluşan volkanik birimin tüm kayaç, Sr-Nd-Pb ve O izotop jeokimyası ile K-Ar jeokronolojisi çalışmaları yapılmıştır. Genel olarak vitrofirik porfirik dokuda gözlenen volkanitlerin bileşimini plajiyoklaz, biyotit, kuvars, sanidin ve amfibol mineralleri oluşturmaktadır. Kalkalkalen afinite gösteren ve yüksek-K içeren volkanitlerin, ana ve iz element değişimleri, kayaçların gelişiminde plajiyoklas, amfibol, biyotit ve alkali feldispat fraksiyonlaşmasının etkili olduğuna işaret etmektedir. Ayrıca yüksek LILE ve LREE ile düşük Nb, Zr, Y ve Ti içerikleri; bu volkanitlerin gelişiminde fraksiyonel kristallenme, kabuk katkısı ve/veya asimilasyonun kayaçların oluşumunda önemli bir rol oynadığını ve ana magmalarının zenginleşmiş bir kaynaktan türediğine işaret etmektedir. Tüm kayaç K-Ar yaşlandırma yöntemi ile, incelenen volkanitlere ait örneğin yaşının 21.4±0.6 My olduğunu göstermektedir. Elde edilen izotop sonuçlarına göre; (87Sr/86Sr)i oranı 0.708885, (143Nd/144Nd)i oranı 0,512347 206Pb/204Pb izotop oranı 19.04, 207Pb/204Pb izotop oranı 15,6790 ve 208Pb/204Pb izotop oranı 37.9130 ve δ18O oranı ise 11.3 ‰ olarak belirlenmiştir. Elde edilen jeokronolojik, jeokimyasal ve izotopik veriler incelenen volkanitlerin volkanik yay ortamında oluştuğunu ve oluşumunda fraksiyonel kristallenme ile beraber ayrıca kaynak manto bölgesinde zenginleşme ve kabuk kirliliğinin/asimilasyon (AFC) süreçlerinin etkisini taşıdığını işaret etmektedir.

Anahtar Kelimeler

• Miyosen volkanitleri
• K-Ar jeokronolojisi
• Sr-NdPb ve O izotop jeokimyası
• Emet bor havzası
• Kütahya

Petrography and geochemistry of Bahatlar volcanites (Emet-Kütahya)

Abstract

In western Anatolia, volcanic rocks in the Eocene-Quaternary age range are widely outcropped. Early Miocene volcanites are represented as andesite, dacite and rhyolites in Kütahya and its surroundings. In this study, the whole rock, Sr-Nd-Pb and O isotope geochemistry and K-Ar geochronology data of the volcanic unit consisting of rhyolites outcropping in the Emet Borate Basin will be presented. Petrographic properties of the studied volcanites are generally observed in the porphyritic vitrophyric texture, and their composition consists of plagioclase, biotite, quartz, sanidine and amphibole minerals. The major and trace element variation of the volcanites, which have calc-alkaline affinity and contain high-K, indicate that plagioclase, amphibole, biotite and alkali feldspar fractionation is effective in the evolution of rocks. In addition, high LILE and LREE and low Nb, Zr, Y and Ti contents indicate that fractional crystallization, crustal contamination and/or assimilation play an important role in the evolution of volcanites and that their main magmas are derived from an enriched source. The whole rock K-Ar aging method shows that the age of the sample belonging to the studied volcanites is 21.4±0.6 Ma. According to the obtained isotope results, (87Sr/ 86Sr)i ratio is 0.708885, ( 143Nd/144Nd) i ratio is 0.512347206Pb/204Pb isotope ratio 19.04, 207Pb /204Pb isotope ratio is 15.6790 and 208Pb/204Pb isotope ratio is 37.9130 and δ18O ratio is 11.3 ‰. The obtained geochronological, geochemical, and isotopic data indicate that the investigated volcanites were formed in the volcanic arc environment and that fractional crystallization, as well as enrichment in the source mantle area and crustal pollution / assimilation (AFC) processes, have been influenced in their evolution.

Keywords

• Miocene volcanites
• K-Ar geochronology
• Sr-Nd-Pb and O isotope geochemistry
• Emet borate basin
• Kütahya.

Kaynakça

1. [1] Akdeniz N, Konak N. “Simav-Emet-Dursunbey-Demirci Yörelerinin Jeolojisi”. MTA Derleme Raporu, Ankara, Türkiye, 1979.
2. [2] Gün H, Akmaz N, Günay E. “Gediz ve emet güneyi neojen havzalarının jeolojisi ve yaş sorunları”. Jeoloji Mühendisliği Dergisi, 8, 1-13, 1979.
3. [3] Yılmaz Y. An approach to the origin of young volcanic rocks of western Turkey. Tectonic Evolution of the Techyan. Editor: Şengör AMC. Tectonic Evolution of the Tethyan Region, 159-189, Dordrecht, Netherlands, Kluwer Academic Publishers, 1989.
4. [4] Yılmaz Y. “Comparison of young volcanite associations of western and eastern Anatolia formed under a compressional regime: a review”. Journal of Volcanology and Geothermal Research, 44, 1-2, 69-87, 1990.
5. [5] Seyitoǧlu G, Scott, B. “Late Cenozoic crustal extension and basin formation in west Turkey”. Geological Magazine, 128(2), 155-166, 1991.
6. [6] Seyitoğlu G, Anderson D, Nowell G, Scott B. “The evolution from Miocene potassic to Quaternary sodic magmatism in western Turkey: implications for enrichment processes in the lithospheric mantle”. Journal of Volcanology and Geothermal Research, 76, 127-147, 1997.
7. [7] Özkul C, Temizel İ, Özburan M, Arslan M, Kibici Y. “Kütahya Çevresindeki (Batı Anadolu) Miyosen Volkanitlerinin Petrokimyası, K-Ar Jeokronolojisi, Sr-Nd-Pb-O İzotop Jeokimyası ve Jeodinamik Gelişimi”. Tübitak Projesi, Proje No: 113Y069, 2015.
8. [8] Köksal S, Möller A, Göncüoglu MC, Frei D, Gerdes A. “Crustal homogenization revealed by U-Pb zircon ages and Hf isotope evidence from the Late Cretaceous granitoids of the Agaçören intrusive suite (Central Anatolia/Turkey)”. Contributions to Mineralogy and Petrology, 163(4), 725-743, 2012.

9. [9] Clayton RN, Mayeda TK. “The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis”. Geochimica et Cosmochimica Acta, 27(1), 43-52, 1963.
10. [10] Borthwick J, Harmon RS. “A note regarding CIF3 as an alternative to BrF5 for oxygen isotope analysis”. Geochimica et Cosmochimica Acta, 46(9), 1665-1668, 1982.
11. [11] Kraus I, Chernyshev IV, Sucha V, Kovalenker VA, Lebedev VA, Samajova E. “Use of illite for K/Ar dating of hydrothermal precious and base metal mineralization in Central Slovak Neogene volcanite rocks”. Geologica Carpathica, 50(5), 353-364, 1999.
12. [12] Helvacı C, Alonso RN. “Borate deposits of Turkey and argentina; a summary and geological comparison”. Turkish journal of Earth Sciences, 9, 1-27, 2000.
13. [13] Dündar A, Güngör N, Gürsel T, Özden M, Özyeğin E. “Kütahya-Emet Bölgesi Bortuzu Yatağı Nihai Değerlendirme Raporu”. Ankara, Türkiye, 1986.
14. [14] Le Bas MJ, Le Maitre RW, Streckeisen A, Zanettin B, “IUGS Subcommission on the Systematics of Igneous Rocks, A Chemical Classification of Volcanic Rocks Based on the Total Alkali-Silica Diagram”. Journal of Petrology, 27(3), 745-750, 1986.
15. [15] Irvine TN, Baragar WRA. “A Guide to the Chemical Classification of the Common Volcanic Rocks”. Canadian Journal of Earth Sciences, 8(5), 523-548, 1971.
16. [16] Peccerillo A, Taylor SR. “Geochemistry of Eocene calcalkaline volcanite rocks from the Kastamonu area, northern Turkey”. Contributions to Mineralogy and Petrology, 58, 63-81, 1976.
17. [17] Le Maitre, RW. Igneous Rocks: A Classification and Glossary of Terms: Recommendations of the International Union of Geological Sciences Subcommission on the Systematics of Igneous Rocks, 2nd ed. Cambridge, England, Cambridge University Press, 2002.
18. [18] Pearce JA. Role of the Sub-Continental Lithosphere İn Magma Genesis at Active Continental Margins. Editors: Hawkesworth CJ, Norry, MJ. Continental Basalts and Mantle Xenoliths, Shiva, Cheshire, 230-249, 1983.
19. [19] Gill JB. Orogenic Andesites and Plate Tectonics. Berlin, Germany, Springer, 1981.
20. [20] Fitton JG, James, D, Kempton PD, Ormerod DS, Leeman WP. “The role of the lithospheric mantle in the generation of Late Cenezoic basic magmas in the Western United States”. Journal of Petrology, Special Lithospheric Issue, 331-349, 1988.
21. [21] Anders E, Grevesse N. “Abundances of the elements: meteoric and solar”. Geochimica et Cosmochimica Acta, 53, 197-214. 1989.
22. [22] Rollinson HR. Using Geochemical Data: Evoluation, Presentation, Interpretation. London, England, John Wiley Sons. Inc., 1993.
23. [23] Barragan R, Geist D, Hall M, Larson P, Kurz M. “Subduction controls on the compositions of lavas from the Ecuadorian Andes”. Earth and Planetary Science Letters, 154(1-4), 153-166, 1998.
24. [24] Fitton, JG, James D, Leeman WP. “Basic magmatism associated with late cenozoic extension in the western united states: compositional variations in space and time”. Journal of Geophysical Research, 96(B8), 13693-13711, 1991.
25. [25] Aydınçakır E. Borçka (Artvin, Kd-Türkiye) Yöresi Tersiyer Volkanitlerinin Petrografisi, Jeokimyası ve Petrojenezi. Doktora Tezi, Karadeniz Teknik Üniversitesi, Trabzon, Türkiye, 2012.
26. [26] Kaygusuz A, Arslan, M, İlbeyli N, Sipahi F. “Doğu Pontid Kuzey Zonu ve Kuzey-Güney Zon Geçişinde Yüzeylenen Kretase-Paleosen Yaşlı Granitoyidik Sokulumların Petrokimyası, Sr-Nd-Pb-O izotop Jeokimyası, Jeokronolojisi ve Jeodinamik Gelişimi”. Tübitak Projesi, Proje No: 109Y052, 2012.
27. [27] Jahn BM, Wu FY, Lo CH. “Crust-mantle interaction induced by deep subduction of the continental crust: geochemical and Sr-Nd isotopic evidence from post-collisional maficultramafic intrusions of the northern Dabie Complex, Central China”. Chemical Geology, 157, 119-146, 1999.
28. [28] Jahn BM, Zhang ZQ. “Archean granulite gneisses from eastern Hebei Province, China: rare earth geochemistry and tectonic implications”. Contributions to Mineralogy and Petrology, 85, 224-243, 1984.
29. [29] Sun S, McDonough WF. Chemical and Isotopic systematics of Oceanic Basalt: Implications for Mantle Composition and Processes, Editors: Saunders AD, Norry MJ. Magmatism in the Ocean Basins, 313-345, London, England, Geological Society of London Special Publication, 1989.
30. [30] Pearce. JA. Trace element characteristics of lavas from destructive plate margins. Editors: Thorpe RS. Andesites: Orogenic Andesites and Related Rocks, New York, USA, Wiley, 1982.
31. [31] Wedepohl KH. “The composition of the continental crust”. Geochimica et Cosmochimica Acta, 59, 1217-1239, 1995.
32. [32] Faure G, Mensing TM. Isotopes: Principles and Applications, 3rd ed. Hoboken, New Jersey, USA, John Wiley and Sons, 2005.
33. [33] Prelević D, Foley SF, Romer R, Conticelli S. “Mediterranean Tertiary lamproites derived from multiple source components in post collisional geodynamics”. Geochim Cosmochim Acta, 72, 2125-2156, 2008.
34. [34] Karaoğlu Ö, Helvacı C, Ersoy EY. “Petrogenesis and 40Ar/39Ar geochronology of the volcanite rocks of the Uşak-Güre basin, western Turkey”. Lithos, 119, 193-210, 2010.
35. [35] Ersoy EY, Helvacı C, Palmer MR. “Petrogenesis of the Neogene volcanite units in the NE-SW-trending basins in western Anatolia, Turkey”. Contributions to Mineralogy and Petrology, 163, 379-401, 2012.
36. [36] Semiz B, Ersoy EY, Özpınar Y, Helvacı C, Palmer MR, Billor MZ. “ 40Ar/39Ar Geochronology, geochemistry and petrology of volcanite rocks from the Simav Graben, western Turkey”. Contributions to Mineralogy and Petrology, 170, 24, 1-24, 2015.
37. [37] Zindler A, Hart SR. “Chemical geodynamics”. Annual Review of Earth and Planetary Sciences, 14, 493-571, 1986.
38. [38] Hart SR, Hauri E, Oschmann L, Whitehead J. “Mantle plumes and entrainment: isotopic evidence”. Science, 256, 517-520, 1992.
39. [39] Wilson M. Igneous Petrogenesis. Oxford, England, Oxford University Press, 1989.
40. [40] Arculus, RJ, Powell R. “Source component mixing in the regions of are magma generation”. Journal of Geophysical Research, 91, 5913-5926, 1986.
41. [41] McCulloch, MT, Gamble, JA. “Geochemical and geodynamical constraints on subduction zone magmatism”. Earth and Planetary Science Letters, 102, 358-374, 1991.
42. [42] Davies, JH, von Blanckenburg F. “Slab breakoff: a model of lithospheric detachment and its test in the magmatism and deformation of collisional orogens”. Earth Planet Science Letter, 129, 85-102, 1995.
43. [43] Doe BR, Zartman RE. Plumbotectonics I, The Phanerozoic. Editors: Barnes HL. Geochemistry of Hydrothermal Ore Deposits, 22-70, New York, USA, Wiley Interscience, 1979.
44. [44] James DE. “The combined use of oxygen and radiogenic isotopes as indiators of crustal contamination”. Annual Review of Earth and Planetary Sciences, 9, 311-344, 1981.
45. [45] Çoban H, Karacık Z, Ece ÖI. “Source contamination and tectonomagmatic signals of overlapping Early to Middle Miocene orogenic magmas associated with shallow continental subduction and asthenospheric mantle flows in Western Anatolia: A record from Simav (Kütahya) region”. Lithos, 140, 119-141, 2012.
46. [46] Ersoy YE. Stratigraphy, Tectonic Evolution and Petrogenesis of the Volcanic Rocks in the Gördes, Demirci and Emet Basins (Western Anatolia). Doktora Tezi, Dokuz Eylül Üniversitesi, İzmir, Türkiye, 2011.