GEOLOGY OF THE EARLY MIOCENE ALAÇAMDAĞ (DURSUNBEY-BALIKESİR) MAGMATIC COMPLEX AND IMPLICATIONS FOR THE WESTERN ANATOLIAN EXTENSIONAL TECTONICS

Yıl 2010, Cilt: 141 Sayı: 141, 1 - 25, 01.10.2010

Fuat Erkül , Sibel Tatar Erkül

Öz

The extensional regime in western Anatolia caused the development of metamorphic core complexes, NE and E-W-trending basins and emplacement of magmatic rocks since Late Oligocene and Early Miocene. The Alaçamdağ magmatic complex, which is located to the west of the Simav metamorphic core complex, includes significant data that highlight the style of the extensional regime in western Turkey. It consists of Early Miocene granitic intrusions and volcanic rocks with variable compositions ranging from basalt to rhyolite. The granitic intrusions that were emplaced into the basement rocks of the Menderes Massive and İzmir-Ankara Zone are divided into two facies based on their lithological and textural characteristics: Musalar and Alaçam granites. The Musalar granite has typical holocystalline equigranular texture, while the Alaçam granite is characterised by its porphyritic texture defined by abundant K-feldspar megacrysts. Both granite units were locally transformed into mylonites along shear zones. Volcanic rocks consist of Saðýrlar volcanic unit and felsic volcanic rocks. Sağırlar volcanic unit is made up of andesitic/dacitic intrusions, domes, lava flows, dykes and volcanogenic sedimentary rocks. The felsic volcanic rocks, which unconformably overlies the Saðýrlar volcanic unit, consist of ignimbrite, dacite and rhyolite. These rocks have transitional contacts with alluvial/lacustrine sedimentary deposits. Ductile deformation on the granitic rocks, intra-basinal unconformities and syn-sedimentary deformational structures within the deposits are closely associated with the development of extensional regime during Early Miocene in western Turkey.

Anahtar Kelimeler

Stratigraphy, ductile deformation, extensional tectonics, volcano-sedimentary successions, northwestern Anatolia

Kaynakça

• Akdeniz, N. and Konak, N. 1979. Menderes Masifi'nin Simav dolayýndaki kaya birimleri ve metabazik, metaultramafik kayalarýn konumu. Türkiye Jeoloji Kurumu Bülteni, 22, 175-183.
• Akyürek, B. and Soysal, Y. 1982. Biga yarýmadasý güneyinin (Savaþtepe Kýrkaðaç-BergamaAyvalýk) temel jeoloji özellikleri. Maden Tetkik Arama Enstitüsü Dergisi, 95/96, 1-12.
• Aldanmaz, E., Pearce J., Thirlwall, M. F, and Mitchell, J. G., 2000. Petrogenetic evolution of Late Cenozoic, post-collision volcanism in western Anatolia, Turkey. Journal of Volcanology and Geothermal Research, 102 1-2, 67-95.
• Altunkaynak, Þ. and Yýlmaz, Y. 1998. The Mount Kozak Magmatic Complex, Western Anatolia. Journal of Volcanology and Geothermal Research, 85 1-4, 211-231.
• Altunkaynak, Þ., and Dilek, Y., 2006. Timing and nature of postcollisional volcanism in western Anatolia and geodynamic implications. Geology Society of American Special Paper, 409, 321-351
• Bingöl, E., Delaloye, M. and Ataman, G. 1982. Granitic intrusions in Western Anatolia: A contribution to the geodynamic study of this area. Eclogae Geologica Helvetica, 75, 437-446.
• Borsi, J., Ferrara, G., Innocenti, F. and Mazzuoli, R. 1972. Geochronology and petrology of recent volcanics in the easthern Aegean Sea (West Anatolia and Lesvos Island). Bulletin of Volcanology, 36, 473-496.
• Bozkurt, E. 2000. Timing of extension on the Büyük Menderes Graben, western Turkey, and its tectonic implications. Geological Society, London, Special Publications, 173 1, 385-403.
• ,2001a. Late Alpine evolution of the central Menderes Massif, Western Anatolia, Turkey. International Journal of Earth Sciences, 89, 728-744.
• ,2001b. Neotectonics of Turkey-a synthesis. Geodinamica Acta, 14 (1-3), 3-30. ,2003. Origin of NE-trending basins in western Turkey. Geodinamica Acta, 16, 61-81.
• ,2004. Granitoid rocks of the southern Menderes Massif (southwestern Turkey): field evidence for Tertiary magmatism in an extensional shear zone. International Journal of Earth Sciences 93 (1), 52-71.
• and Park, R.G. 1994. Southern Menderes Massif-an incipient metamorphic core complex in western Anatolia, Turkey. Journal of the Geological Society, 151, 213-216.
• and , 1997a. Microstructures of deformed grains in the augen gneisses of southern Menderes Massif (western Turkey) and their tectonic significance. Geologische Rundschau 86 (1), 103-119.
• and , 1997b. Evolution of a mid-Tertiary extensional shear zone in the southern Menderes massif, western Turkey. Bulletin De La Societe Geologique De France 168 1, 3-14.
• Bozkurt, E. and Oberhänsli, R. 2001. Menderes Massif (Western Turkey): Structural, metamorphic and magmatic evolution-a synthesis. International Journal of Earth Sciences, 89, 679-708.
• and Sözbilir, H. 2004. Tectonic evolution of the Gediz Graben: field evidence for an episodic, two-stage extension in Western Turkey. Geological Magazine, 141 1, 63-79.
• Delaloye, M. and Bingöl, E. 2000. Granitoids from Western and Northwestern Anatolia: Geochemistry and modeling of geodynamic evolution. International Geology Review, 42 3, 241- 268.
• Dilek, Y. and Altunkaynak, Þ., 2007. Cenozoic crustal evolution and mantle dynamics of post-collisional magmatism in western Anatolia. International Geology Review, 49, 431-453.
• Ercan, T. 1979. Batý Anadolu, Trakya ve Ege adalarýndaki Senozoyik volkanizmasý. Jeoloji Mühendisliði Dergisi, 10, 23-46.
• ,1982. Batý Anadolu Tersiyer volkanitleri ve Bodrum yarýmadasýndaki volkanizmanýn durumu. Ýstanbul Yerbilimleri Dergisi, 2, 263-281.
• and Öztunalý, Ö. 1983. Demirci-Selendi çevresinde Senozoyik yaþlý volkanitlerin petrolojisi ve kökensel yorumu. Yerbilimleri, 10, 1-15.
• ,Satýr, M., Kreuzer, H., Türkecan, A., Günay, E., Çevikbaþ, A., Ateþ, M. and Can, B. 1985. Batý Anadolu Senozoyik volkanitlerine ait yeni kimyasal, izotopik ve radyometrik verilerin yorumu. Türkiye Jeoloji Kurumu Bülteni, 28, 121-136.
• Erdoðan, B. 1990a. Tectonic relations between IzmirAnkara Zone and Karaburun Belt. Bulletin of the Mineral Research and Exploration Institute of Turkey, 110, 1-15.
• ,Altýner, D., Güngör, T., and Özer, S. 1990b. Stratigraphy of Karaburun Peninsula. Bulletin of the Mineral Research and Exploration Institute of Turkey, 111, 1-20
• Erdoðan, B. and Güngör, T. 2004. The problem of the core-cover boundary of the Menderes Massif and an emplacement mechanism for regionally extensive gneissic granites, western Anatolia (Turkey). Turkish Journal of Earth Sciences 13 1, 15-36.
• Erkül, F., 2010. Tectonic significance of synextensional ductile shear zones within the Early Miocene Alaçamdað granites, northwestern Turkey. Geology Magazine, 1-27.
• ,Helvacý, C. and Sözbilir, H. 2005a. Evidence for two episodes of volcanism in the Bigadic borate basin and tectonic implications for western Turkey. Geological Journal 40, 545- 570.
• , and , 2005b. Stratigraphy and geochronology of the Early Miocene volcanic units in the Bigadiç borate basin, Western Turkey. Turkish Journal of Earth Sciences, 14 3, 227-253.
• ,Tatar-Erkül, S., Bozkurt, E, Sözbilir, H., and Helvacý, C., 2009a. Tectonic significance of ductile shear zones within the syn-extensional Alaçamdag granite, northwestern Turkey. 62. Geological Kurultai of Turkey, Abstract, 178- 179.
• Erkül S.T., Erkül, F., Bozkurt, E., Sözbilir, H. and Helvacý, C., 2009b. Geodynamic setting of the early Miocene Alaçamdag volcano-plutonic complex based on petrologic, isotopic and geochronological data: northwestern Turkey. 62. Geological Kurultai of Turkey, Abstract, 180-181.
• Ersoy, Y., Helvacý, C., Sözbilir, H., Erkül, F. and Bozkurt, E. 2008. A geochemical approach to Neogene-Quaternary volcanic activity of western Anatolia: An example of episodic bimodal volcanism within the Selendi Basin, Turkey. Chemical Geology, 255(1-2), 265-282.
• Genç, C. Þ. 1998. Evolution of the Bayramiç Magmatic Complex, Northwestern Anatolia. Journal of Volcanology and Geothermal Research, 85, 233-249.
• Gessner, K., Ring, U., Johnson, C., Hetzel, R., Passchier, C.W., and Güngör, T. 2001. An active bivergent rolling-hinge detachment system; central Menderes metamorphic core complex in western Turkey. Geology, 29, 611- 614.
• Glodny, J., and Hetzel, R. 2007. Precise U-Pb ages of syn-extensional Miocene intrusions in the central Menderes Massif, western Turkey. Geological Magazine 144 (2), 235-246.
• Hasözbek, A., Satýr, M., Erdoðan, B., Akay, E., and Siebel, W. 2009. KB Anadolu'daki çarpýþmaya baðlý granitlerin U-Pb Jeokronolojisi, Sr-Nd izotop jeokimyasý ve Petrojenetik Evrimlerinin Karþýlaþtýrýlmasý. 62. Türkiye Jeoloji Kurultayý, 13-17 Nisan 2009, Maden Tetkik ve Arama Genel Müdürlüðü, Ankara.
• , , , and (in press). Early Miocene post-collisional magmatism in NW Turkey: geochemical and geochronological constraints. International Geology Review.
• Helvacý, C. 1995. Stratigraphy, mineralogy and genesis of the Bigadiç Borate deposits, Western Turkey. Economic Geology, 90, 1237-1260.
• and Alonso, R.N. 2000. Borate deposits of Turkey and Argentina: A summary and geological comparison. Turkish Journal of Earth Sciences, 24, 1-27.
• Hetzel, R., Passchier, C.W., Ring, U., and Dora, O.O. 1995a. Bivergent Extension in Orogenic Belts: the Menderes Massif (Southwestern Turkey). Geology, 23 (5), 455-458.
• ,Ring, U., Akal, C., and Troesch, M. 1995b. Miocene NNE-directed extensional unroofing in the Menderes Massif, southwestern Turkey. Journal of the Geological Society London, 152, 639-654.
• Innocenti, F. and Mazzuoli, R. 1972. Petrology of Ýzmir-Karaburun volcanics (west Turkey). Bulletin of Volcanology, 36, 1-22.
• Iþýk, V and Tekeli, O., 2001. Late orogenic crustal extension in the northern Menderes massif (western Turkey): evidence for metamorp core complex formation. International Journal of Earth Sciences, 89 4, 757-765.
• Iþýk, V., Seyitoðlu, G., and Çemen, Ý., 2003. Ductilebrittle transition along the Alasehir detachment fault and its structural relationship with the Simav detachment fault, Menderes massif, western Turkey. Tectonophysics, 374 1-2, 1-18.
• ,Tekeli, O., and Seyitoðlu, G., 2004. The Ar-40/Ar-39 age of extensional ductile deformation and granitoid intrusion in the northern Menderes core complex: implications for the initiation of extensional tectonics in western Turkey. Journal of Asian Earth Sciences, 23 4, 555-566.
• Ýnci, U. 1998. Lignite and carbonate deposition in Middle Lignite succession of the Soma Formation, Soma coalfield, western Turkey. International Journal of Coal Geology, 37, 287- 313.
• Karacýk, Z. and Yýlmaz, Y., 1998. Geology of the ignimbrites and the associated volcano-plutonic complex of the Ezine area, northwestern Anatolia. Journal Vof Volcanology and Geothermal Research, 85 1-4, 251-264.
• Koçyiðit, A., Yusufoðlu, H., and Bozkurt, E. 1999. Evidence from the Gediz graben for episodic two-stage extension in western Turkey. Journal of the Geological Society, 156, 605-616.
• Krushensky, R.D. 1976. Volcanic rocks of Turkey. Bulletin of Geological Survey Japan, 26, 393.
• Okay, A.Ý. and Siyako, M. 1993. The revised location of the Ýzmir-Ankara Suture in the region between Balýkesir and Ýzmir (In Turkish). Tectonics and Hydrocarbon Potential of Anatolia and Surrounding Regions, 333-355.
• and Tüysüz, O. 1999. Tethyan Sutures of northern Turkey. In: B. Durand, L. Jolivet, F. Horvath ve M. Seranne (Eds.), Mediterranean Basins: Tertiary extension within the Alpine Orogen. Geological Society of London Special Publication, 475-515.
• and Satýr, M. 2000. Coeval plutonism and metamorphism in a latest Oligocene metamorphic core complex in northwest Turkey. Geological Magazine, 137/5, 495-516.
• Pe-Piper, G. and Piper, D.J.W. 1989. Spatial and temporal variation in Late Cenozoic back-arc volcanic rocks, Aegean Sea region. Tectonophysics, 169, 113-134.
• and , 2001. Late Cenozoic, postcollisional Aegean igneous rocks: Nd, Pb and Sr isotopic constraints on petrogenetic and tectonic models. Geological Magazine, 138 6, 653-668.
• Purvis, M. and Robertson, A. 2004. A pulsed extension model for the Neogene-Recent E-W-trending Alasehir Graben and the NE-SW-trending Selendi and Gordes Basins, western Turkey. Tectonophysics, 391 1-4, 171-201.
• Rimmele, G., Jolivet, L., Oberhänsli, R., and Goffe, B. 2003a. Deformation history of the highpressure Lycian Nappes and implications for tectonic evolution of SW Turkey. Tectonics 22 2, 1-21.
• ,Oberhänsli, R., Goffe, B., Jolivet, L., Candan, O., and Çetinkaplan, M. 2003b. First evidence of high-pressure metamorphism in the "Cover Series" of the southern Menderes Massif. Tectonic and metamorphic implications for the evolution of SW Turkey. Lithos 71 1, 19-46.
• Ring, U., Laws, S., and Bernet, M. 1999. Structural analysis of a complex nappe seqýuence and late orogenic basins from the Aegean Island of Samos, Greece. Journal of Structural Geology, 21 11, 1575-1601.
• ,Johnson, C., Hetzel, R., and Gessner, K. 2003. Tectonic denudation of a Late CretaceousTertiary collisional belt: regionally symmetric cooling patterns and their relation to extensional faults in the Anatolide belt of western Turkey. Geological Magazine, 140 4, 421-441.
• and Collins, A.S. 2005. U-Pb SIMS dating of synkinematic granites: Timing of core-complex formation in the northern Anatolide belt of western Turkey. Journal of the Geological Society, 162, 289-298.
• Savaþçýn, M. Y. and Güleç, N. 1990. Relationship between magmatic and tectonic activities in western Turkey. In: M.Y. Savaþçýn and A.H. Eronat (Eds.), International Earth Science Colloquum on the Aegean Region (IESCA) Proceedings, 300-313.
• Seyitoðlu, G. 1997. Late Cenozoic tectono-sedimentary development of the Selendi and UsakGure basins: a contribution to the discussion on the development of east-west and north trending basins in western Turkey. Geological Magazine, 134, 163-175.
• and Scott, B. 1992. Late Cenozoic volcanic evolution of the northeastern Aegean region. Journal of Volcanology and Geothermal Research, 54, 157-176.
• ,Anderson, D., Nowell, G., and Scott, B. 1997. 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.
• ,Tekeli, O., Çemen, Ý., Þen, S., and Iþýk, V. 2002. The role of the flexural rotation/rolling hinge model in the tectonic evolution of the Alaþehir graben, western Turkey. Geological Magazine, 139 1, 15-26.
• Sözbilir, H. 2001. Extensional tectonics and the geometry of related macroscopic structures with their relations to the extensional tectonics: Field evidence from the Gediz detachment, western Turkey. Turkish Journal of Earth Sciences, 10, 51-67.
• ,2002a. Geometry and origin of folding in the Neogene sediments of the Gediz Graben, western Anatolia, Turkey. Geodinamica Acta, 15 5-6, 277-288.
• Sözbilir, H. 2002b. Revised stratigraphy and facies analysis of Palaeocene - Eocene supraallochthonous sediments (Denizli, SW Turkey) and their tectonic significance. Turkish Journal of Earth Sciences, 11, 87-112.
• Þengör, A. M. C. 1984. Timing of tectonic events in the Menderes massif, Western Turkey: implications for tectonic evolution and evidence for PanAfrican basement in Turkey. Tectonics, 3 7, 693-707.
• Thomson, S.N. and Ring, U. 2006. Thermochronologic evaluation of postcollision extension in the Anatolide orogen, western Turkey. Tectonics, 25 3.
• Westaway, R. 2006. Cenozoic cooling histories in the Menderes Massif western Turkey, may be caused by erosion and flat subduction, not low-angle normal faulting. Tectonophysics, 412 1-2, 1-25.
• Whitney, D. L. and Bozkurt, E. 2002. Metamorphic history of the southern Menderes massif, western Turkey. Geological Society of America Bulletin 114 7, 829-838.
• Yýlmaz, Y., Genç, S.C., Gürer, F., Bozcu, M., Yýlmaz, K., Karacýk, Z., Altunkaynak, Þ. and Elmas, A. 2000. When did the western Anatolian grabens begin to develop? In: E. Bozkurt, J.A.
• Winchester ve J.D.A. Piper (Eds.), Tectonics and Magmatism in Turkey and the Surrounding Area. Geological Society, London, Special Publications, 353-384.
• , , Karacýk, Z. and Altunkaynak, Þ. 2001. Two contrasting magmatic associations of NW Anatolia and their tectonic significance. Journal of Geodynamics, 31, 243-271.