Geochemistry, origin and tectonic setting of the Örenli metamorphics (Canakkale, Biga Peninsula, NW Turkey)

Öz

Orenli metamorphics (Canakkale) expose on the southern part of the Biga Peninsula in the northwest Turkey. Metamorphic rocks chiefly consist of metapelite. metabasite and marble intercalations based on the macroscopic and petrographic observations. Schists occurring within the Örenli metamorphics are the dominant lithology and yellowish brown-colored. fine to medium-grained and well-foliated. Petrographical analyses show that quartz. chlorite. K-feldspar. biotite and muscovite form the main mineralogical composition of schists. Biotite minerals are replaced by the chlorite minerals. which shows that Orenli metamorphics are low-grade metamorphic rocks underwent greenschist-facies metamorphism. The abundance of K-feldspar within the schists states that fast sediment deposition took place from proximal source. Whole-rock geochemical analyses were performed to find out tectonic setting and origin of the Orenli metamorphics. Provenance discrimination diagrams in terms of major element geochemistry and trace element ratios (i.e., Zr/Sc, Th/Sc and Cr/V) suggest that Orenli metamorphics were dominantly derived from the intermediate-felsic source rocks are the origin of sediments. The crystalline basement of the Sakarya Zone in northwest Turkey could be possible source areas of this low-grade metamorphic rocks. which is made up of Carboniferous. Devonian metamorphic and magmatic rocks. Major and immobile trace elements for tectonic setting (i.e., Th-Sc-Zr/10 and Th- Co- Zr/10) and La/Y vs. Sc/Cr plots exhibit those metamorphic rocks were deposited in an oceanic island arc and passive margin. The metapelitic rocks could have double origin based on the petrographical and geochemical results. The quartz and metamorphic fragments derived from the continent form the first origin. The other origin is plagioclase. feldspar. and volcanic fragments originated from the volcanic-arc type. On the other hand. the metapelitic rocks were originated from both continental source and volcanic arc areas showing the back-arc basin.

Anahtar Kelimeler

• Geochemistry
• Örenli metamorphics
• Provenance
• Biga Peninsula
• NW Turkey

Örenli metamorfitlerinin jeokimyası, kökeni ve tektonik yerleşimi (Çanakkale, Biga Yarımadası, KB Türkiye)

Öz

Örenli metamorfitleri (Çanakkale) KB Türkiye’de Biga Yarımadası’nın güney kesiminde yüzlek vermektedir. Makroskobik ve petrografik gözlemlere dayanarak bu kayalar başlıca metapelit. metabazit ve mermer ardalanmasından oluşmaktadır. Örenli metamorfitlerinde baskın litolojiyi oluşturan şistler sarımsı kahverenkli. iyi foliasyonlu ve ince-orta kristallidir. Petrografik analizler şistlerin başlıca kuvars, Klorit, feldspat ve mika mineralleri içerdiğini göstermektedir. Klorit minerallerinin biyotit minerallerinden dönüşmüş olarak gözlenmesi Örenli metamorfitlerinin yeşilşist fasiyesinde metamorfizma geçirmiş düşük dereceli metamorfik kayalar olduğunu işaretler. Şistler içerisindeki feldspatların bolluğu yakındaki kaynak kayalarından hızlı bir sediment çökeliminin olduğunu belirtir. Bu metamorfik kayalardan kaynak alanlarının. çökelme havzalarının ve tektonik ortamlarının ortaya çıkarılması amacıyla ana. iz ve nadir toprak elementi analizleri yapılmıştır. Ana element jeokimyası ve iz element oranları (örneğin Th/Sc, La/Th, Cr/V ve Y/Ni) ise bu tür kayaların baskın olarak ortaç-felsik bileşimde olan kaynak kayalarından türediğini ifade etmektedir. Benzer şekilde Örenli metamorfitlerinin olası kaynak alanları Devoniyen ve Karbonifer yaşlı kayalardan oluşan Sakarya Zonu’nun kristalin temelidir. Ana ve hareketsiz iz elementlere (örneğin Th-Co-Zr/10 ve Th-Sc-Zr/10) ve La/Y-Sc/Cr oranlarına dayanılarak oluşturulan tektonik ortam ayrım diyagramlarında metapelitik kayalar pasif kıta kenarı ve okyanusal ada yayı ortamlarında çökelmiştir. Petrografik ve jeokimyasal sonuçlara göre metapelitik kayalar iki farklı kaynaktan türemiş olabilir. Birincisi. kıtasal kaynaktan kuvars ve metamorfik kırıntılar gelmiştir. Diğeri ise volkanik bir yaydan feldspat. plajioklas ve volkanik kırıntılar gelmiştir. Diğer bir deyişle metapelitik kayalar yay gerisi havzada hem aktif volkanik yaydan hem de kıtadan malzeme almıştır.

Anahtar Kelimeler

• Jeokimya
• Örenli metamorfitleri
• Kaynak
• Biga Yarımadası
• KB Türkiye

Kaynakça

1. [1] Dickinson WR, Suczek CA. “Plate tectonics and sandstone compositions”. American Association Petrology, Geology Bulletin, 63, 2164-2182, 1979.
2. [2] Critelli S, Arribas J, Le Pera E, Tortosa A, Marsaglia KM, Latter KK. “The recycled orogenic sand provenance from an uplifted thrust belt, Betic Cordillera, Southern Spain”. Journal of Sedimentary Research, 73 (1), 72-81, 2003.
3. [3] Hara H, Kunii M, Hisada K, Ueno K, Kamata Y, Srichan W. Charusiri P, Charoentitrat T, Watarai M, Adachi Y, Kurihara Y. “Petrography and geochemistry of clastic rocks within the Inthanon zone, northern Thailand: Implications for Paleo-Tethys subduction and convergence”. Journal of Asian Earth Sciences, 61, 2-15, 2012.
4. [4] Nesbitt HW, Young GM. “Prediction of some weathering trends of plutonic and volcanic rocks based on thermodynamic and kinetic considerations”. Geochimica et Cosmochimica Acta, 48, 1523–1534, 1984.
5. [5] Cullers RL. “The geochemistry of shales, siltstones and sandstones of Pennsylvanian–Permian age, Colorado, U.S.A.: implications for provenance and metamorphic studies”. Lithos, 51, 181-203, 2000.
6. [6] Young SM, Pitawala A, Ishiga H. “Geochemical characteristics of stream sediments, sediment fractions, soils, and basement rocks from the Mahaweli River and its catchment, Sri Lanka”. Chemi der Erde-Geochemistry, 73, 357-371, 2013.
7. [7] Tunç İO. The geology of the Kazdağ massif on the south of Bayramiç (Çanakkale),” Master Thesis, Çanakkale Onsekiz Mart University, Çanakkale, Turkey, 2008.
8. [8] Okay AI, Satır M, Siebel W. „Pre-Alpide and Mesozoic orogenic events in the Eastern Mediterranean region”. Geological Society of Special Publication No:32, 389-405, 2006.

9. [9] Meinhold G. Kostopoulos D. Frei D. Himmerkus F. Reischmann T. “U-Pb LA-SF ICP-MS zircon geochronology of the Serbo-Macedonian Massif, Greece: Palaeotectonic constraints for Gondwana-derived terranes in the Eastern Mediterranean”. International Journal of Earth Science, 99, 813-832, 2010.
10. [10] Okay AI, Satır M. “Coeval plutonism and metamorphism in a latest Oligocene metamorphic core complex in Northwest Turkey”. Geological Magazine, 137, 495–516, 2000.
11. [11] Yaltırak C, Okay AI. “Edremit körfezi kuzeyinde Paleotetis birimlerinin jeolojisi“. Bulletin of Engineering of ITU, 3 (1), 67–79, 2004.
12. [12] Duru M, Pehlivan Ş. Ilgar A. Dönmez M. Akçay AE. 1/100000 ölçekli Türkiye Jeoloji Haritaları Serisi: Ayvalık İ17 paftası, MTA, 2007.
13. [13] Cavazza W, Okay AI, Zattin M. “Rapid early-middle Exhumation of the Kazdağ Massif (western Anatolia)”. International Journal of Earth Sciences, 98, 1935-1947, 2009.
14. [14] Şengün F, Çalık A. “Çamlıca Metamorfitlerinin (Biga Yarımadası, KB Türkiye) Metamorfizma Özellikleri ve Korelasyonu”. Türkiye Jeoloji Bülteni, 50, 1–16, 2007.
15. [15] Şengün F, Yigitbas E, Tunç İO. „Geology and Tectonic Emplacement of Eclogite and Blueschist, Biga Peninsula, Northwest Turkey”. Turkish Journal of Earth Sciences, 20, 273–285, 2011.
16. [16] Beccaletto L, Bonev N, Bosch D, Bruguier O. “Record of a Palaeogene syn-collisional extension in the north Aegean Sea: evidence from the Kemer micaschists (NW Turkey)”. Geological Magazine, 144, 393–400, 2007.
17. [17] Aygül M, Topuz G, Okay AI, Satır M, Meyer HP. “The Kemer Metamorphic Complex (NW Turkey), a subducted continental margin of the Sakarya Zone”. Turkish Journal of Earth Sciences, 21, 19–35, 2012.
18. [18] Okay AI, Göncüoğlu MC, “The Karakaya Complex: A Review of data and concepts”. Turkish Journal of Earth Sciences, 13, 77–95, 2004.
19. [19] Okay AI, Siyako M, Bürkan KA. „Biga Yarımadası’nın Jeolojisi ve Tektonik Evrimi. Turkish Association Petroleum Geology Bulletin 2(1), 83–121, 1990.
20. [20] Beccaletto L, Bartolini AC, Martini R, Hochuli PA, Kozur H. „Biostratigraphic data from Çetmi Melange, northwest Turkey: Palaeogeographic and tectonic implications”. Palaeogeography Palaecology, 221, 215–244, 2005.
21. [21] Beccaletto L, Jenny C. “Geology and Correlation of the Ezine Zone: A Rhodope Fragment in NW Turkey?”. Turkish Journal of Earth Sciences, 13, 145–176, 2004.
22. [22] MTA General and economic geology of the Biga Peninsula. Special Publication Series, 28, 2012.
23. [23] Beccaletto L. Geology, correlations and geodynamic evolution of the Biga Peninsula, northwest Turkey, PhD Thesis, University of Lausanne, Lausanne, Switzerland, 2004.
24. [24] Tunç İO. Bayramiç (Çanakkale) Güneyindeki Kazdağ Masifi Kayalarının Jeolojisi. Yüksek Lisans Tezi, Çanakkale Onsekiz Mart Üniversitesi, Çanakkale, Türkiye, 2008.
25. [25] Pettijohn FJ, Potter PE, Siever R. Sand and Sandstone. New York, Springer Verlag, 1972.
26. [26] Nesbitt HW, Young GM. “Prediction of Some Weathering Trends of Plutonic and Volcanic Rocks Based on Thermodynamic and Kinetic Considerations”, Geochimica et Cosmochimica Acta, 48, 1523–1534, 1984.
27. [27] Akdoğan R. Erken-Orta yaşlı kumtaşı ve şeyllerin (Gümüşhane, Bayburt) jeokimyasal özellikleri. Yüksek Lisans Tezi, Karadeniz Teknik Üniversitesi, Trabzon, Türkiye, 2011.
28. [28] Taylor SR, McLennan SM. The Continental Crust: Its Composition and Evolution. Blackwell Scientific Publications, Blackwell, Oxford, UK, 1985.
29. [29] Sun SS, McDonough WF. “Chemical and isotopic systematics of oceanic basalts; implications for mantle composition and processes. Editors: Saunders AD, Norry MJ. Magmatism in the ocean basins, Geological Society of London, 313-345, 1989.
30. [30] Bhatia MR. “Plate tectonics and geochemical compositions of sandstones”. Journal of Geology, 91, 611-627, 1983.
31. [31] Reimer TO. “Volcanics Rocks and Weathering in the Plaleoproterozoic Witwatersand Supergroup, South Africa”. Survey of Finland Bulletin, 331-334, 1985.
32. [32] Cullers RL, Barrett T, Carlson R, Robinson B. “Rare-Earth Element and Mineralogic Cahanges in Holocene Soil and Stream Sediment: A Case Study in the Wet Mountains, Colorado, U.S.A”. Chemical Geology, 63, 275-297, 1987.
33. [33] McLennan SM. Rare Earth Elements in Sedimentary Rocks: Influence of Provenance and Sedimentary Processes. Editors: Lipin BR, MacKay GA. Geochemistry and Mineralogy of Rare Earth Elements, Mineralogical Society of America, 169–200, 1989.
34. [34] Roser BP. Korsch RJ. “Provenance Signatures of Sandstone-Mudstone Suites Determined Using Discrimination Function Analysis of Major-Element Data”. Chemical Geology, 67, 119-139, 1988.
35. [35] McLennan SM, Hemming S, McDaniel DK, Hanson GN. Geochemical approaches to sedimentation, provenance, and tectonics. Editors: Johnsson MJ, Basu A. processes controlling the composition of clastic sediments: Boulder, Colorado, Geological Society of America Special Paper 284, 21-40, 1993.
36. [36] Roddaz M, Viers J, Brusset S, Baby P, Boucayrand C, Hérail G. “Controls on Weathering and Provenance in the Amazonian Foreland Basin: Insights From Major and Trace Element Geochemistry of Neogene Amazonian Sediments”. Chemical Geology, 226, 31–65, 2006.
37. [37] Paul D, White WM, Turcotte DL. “Constraints on the 232Th/238U ratio (K) of the Continental Crust”. Geochemistry Geophysics. Geosystem, 4 (12), 1102, 2003.
38. [38] Bhatia MR, Crook KAW. “Trace element characteristics of graywackes and tectonic setting discrimination of sedimentary basins”. Contributions to Mineralogy and Petrology, 92,181-193, 1986.