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İTÜ Maden Fakültesi İTÜ Avrasya Yerbilimleri Enstitüsü


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İTÜ Maden Fakültesi

İTÜ Avrasya Yerbilimleri Enstitüsü




Türkiye Jeolojisi

Rejyonal Jeolojide Konular


Derslerde işlenen değişik konular ile ilgili kaynakçalar ve bazı konular üzerinde daha ayrıntılı bilgiler aşağıda verilmiştir. Kaynakçalarda koyu renkli ve yıldızlı makalelerin okunması gereklidir.



1. TÜRKİYE'NİN GENEL TEKTONİĞİ
Ketin İ (1983) - Türkiye jeolojisine genel bir bakış. İTÜ Matbaası, 596 pp Istanbul Teknik Üniversitesi Matbaası, Istanbul.

Ketin, İ., 1966, Anadolu'nun tektonik birlikleri. MTA Dergisi, 66, 20-34. (Tectonic units of Anatolia. MTA Bull., 66, 23-34).

Ketin, İ., 1977, Türkiye'nin başlıca orojenik olayları ve paleocoğrafik evrimi. MTA Dergisi, 88, 1-4.

*Şengör, A.M.C., and Y. Yılmaz, 1981, Tethyan evolution of Turkey, a plate tectonic approach: Tectonophysics, v. 75, p. 181-241.

Şengör, A.M.C., 1985, Türkiye'nin tektonik tarihinin yapısal sınıflaması. Ketin Simpozyumu Kitabı, 37-62.

Okay A.I., Şengör A.M.C. & Görür N., 1994, Kinematic history of the opening of the Black Sea and its effect on the surrounding regions. Geology, 22, 267-270.

Okay A.I., Satır M., Maluski H., Monie P., Siyako M., Metzger R. & Akyüz S. (1996) - Paleo- and Neo-Tethyan events in northwest Turkey: geological and geochronological constraints. In: Yin, A. & Harrison, M. (Eds) - Tectonics of Asia, Cambridge University Press, 420-441.



*Okay, A.I., and Tüysüz, O., 1999, Tethyan sutures of northern Turkey. In "The Mediterranean Basins: Tertiary extension within the Alpine orogen" (eds. B. Durand, L. Jolivet, F. Horváth and M. Séranne), Geological Society, London, Special Publication 156, 475-515


2. PALEO-TETİS VE KARAKAYA KOMPLEKSİ PROBLEMİ
Paleo-Tetis ne zaman, nerede kapanmıştır? Paleo-Tetis kenedi Türkiye'de nereden geçmektedir? Paleo-Tetis kuzeye mi yoksa güneye mi dalarak kapanmıştır? Paleo-Tetis'in okyanusal çökelleri hangileridir? Karakaya Kompleksi neyi temsil eder? Karakaya Kompleksi, Paleo-Tetis'in dalma-batma zonu kayaları mıdır, yoksa rift çökelleri midir? Bu gibi konularda derin görüş farkları, çelişkiler mevcut olup, dışarıdan bakan kişilere konu olduğundan çok daha karmaşık görünmektedir. Bu konulardaki son görüşleri irdeleyen bir makalenin referansı aşağıda verilmiştir:

*Okay, A.I. ve Göncüoğlu, M.C. (2004), The Karakaya Complex: A review of data and concepts. Tuırkish Journal of Earth Sciences, 13, 77-95.
Bu makaleye TÜBITAK'ın web sitesinden ulaşmak mümkündür: http://journals.tubitak.gov.tr/earth/
Paleo-Tetis ve Karakaya Kompleksi ile ilgili var olan modeller üç başlık altında toplanabilir.
1. Rift hipotezi
Karakaya Kompleksi çökelleri rift çökelleridir. Bu rift yer yer okyanusa dönüşmüş olabilir. Karakaya Kompleksi'nin deformasyonu riftin kapanmasına bağlı olarak gelişmiştir.
Başlıca kaynaklar
Bingöl, E., Akyürek, B., and Korkmazer, B., 1975, Biga yarımadasının jeolojisi ve Karakaya Formasyonunun bazı özellikleri. Cumhuriyetin 50. Yılı Yerbilimleri Kong. Tebliğleri, MTA Enstitüsü, 70-77.

*Yılmaz, Y., Genç, S.C., Yigitbaş, E., Bozcu, M.,and Yılmaz, K., 1994, Kuzeybatı Anadoluda Geç Kretase yaşlı kıta kenarının jeolojik evrimi. Proceedings of the 10th Petroleum Congress of Turkey, p. 37-55.

Yılmaz, Y., Genç, S.C., Yigitbaş, E., Bozcu, M.,and Yılmaz, K., 1994, Geological evolution of the late Mesozoic continental margin of northwestern Anatolia. Tectonophysics, 243, 155-171.
2. Kimmeriyen kıtası hipotezi
Permo-Triyas'ta Gondwana kıtasından ince ve uzun bir kıtasal parça (Kimmeriyen kıtası) kopmuş, bu parça kuzeye hareket ederek, kuzeyinde var olan Paleo-Tetis'i kapanmasına ve güneyinde yer alan Neo-Tetis'in açılmasına yol açmıştır. Kimmeriyen kıtası Jurasik'de Lavrasya ile çarpışarak Kimmeriyen orojenezine yol açmıştır.
Karakaya Kompleksi Kimmeriyen kıtası üzerinde, Paleo-Tetis'in güneyinde, Triyas'ta açılmış ve kapanmış bir rift veya dar bir okyanusun kayalarıdır.
Karakaya Kompleksi kayaları ile Paleo-Tetis'in kayaları birbirinden farklıdır. Orta Pontidler'deki Jurasik öncesi kayalar Paleo-Tetis ile ilişkilidir.
Başlıca kaynaklar
Şengör, A.M.C., 1979, Mid-Mesozoic closure of Permo-Triassic Tethys and its implications. Nature, 279, 590-593.

Şengör, A.M.C., Y. Yılmaz, and İ Ketin, 1980, Remnants of a pre-Late Jurassic ocean in northern Turkey, Fragments of Permo-Triassic Paleo-Tethys ?: Geological Society of America Bulletin, v. 91, p. 599-609.

Şengör, A.M.C., Y. Yılmaz, and İ Ketin, 1980, Remnants of a pre-Late Jurassic ocean in northern Turkey, Fragments of Permo-Triassic Paleo-Tethys ?: Discussion and Reply, Geological Society of America Bulletin, v. 93, p. 929-936.

*Şengör, A.M.C., and Y. Yılmaz, 1981, Tethyan evolution of Turkey, a plate tectonic approach: Tectonophysics, v. 75, p. 181-241.

Şengör, A.M.C., 1984, The Cimmeride orogenic system and the tectonics of Eurosia. Geol. Soc. Am. Spec. Paper, 195, 77 pp.

Şengör A.M.C., Yılmaz Y. & Sungurlu O., (1984) - Tectonics of the Mediterranean Cimmerides: nature and evolution of the western termination of Palaeo-Tethys. In: Dixon, J.E. & Robertson, A.H.F. (Eds.) - The Geological Evolution of the Eastern Mediterranean. Geol. Soc. London Spec. Publ., no. 17, pp. 77-112, London.

Şengör, A.M.C., 1985, Türkiye'nin tektonik tarihinin yapısal sınıflaması. Ketin Simpozyumu Kitabı, 37-62.
3. Dalma-batma orojenezi hipotezi
Karakaya kompleksi Triyas yaştaki bir dalma-batma zonunda oluşmuş eklenir prizma kayalarını temsil eder (subduction-accretion complex). Geç Triyas yaştaki Kimmeriyen orojenezi bir okyanus platosunun, veya birçok okyanusal adanın, dalma-batma zonunu tıkaması sonucu meydana gelmiştir. Kimmeriyen kıtası mevcut değildir. Karakaya Kompleksi, Paleo-Tetis'in okyanusal kayalarını ve Paleo-Tetis kapanırken oluşan kayaları temsil eder.
Başlıca kaynaklar
Tekeli O. (1981) - Subduction complex of pre-Jurassic age, northern Anatolia, Turkey. Geology, v. 9, pp. 68-72, Boulder.

*Okay, A.I., Satır, M., Maluski, H., Siyako, M., Monie, P., Metzger, R. and Akyüz S., 1996, Paleo- and Neo-Tethyan events in northwest Turkey: geological and geochronological constraints. in Tectonics of Asia (ed. A. Yin & M. Harrison), Cambridge University Press, 420-441.

Pickett, E., Robertson, A.H.F., 1996. Formation of the Late Paleozoic-Early Mesozoic Karakaya Complex and related ophiolites in NW Turkey by Paleotethyan subduction-accretion. J. Geol. Soc. London 153, 995-1009.

Okay, A.I. and Monié, P., 1997, Early Mesozoic subduction in the Eastern Mediterranean: Evidence from Triassic eclogite in northwest Turkey. Geology, 25, 595-598.

Okay, A.I., and Tüysüz, O., 1999, Tethyan sutures of northern Turkey. In "The Mediterranean Basins: Tertiary extension within the Alpine orogen" (ed. B. Durand, L. Jolivet, F. Horváth and M. Séranne), Geological Society, London, Special Publication 156, 475-515.

*Okay, A.I., 2000, Was the Late Triassic orogeny in Turkey caused by the collision of an oceanic plateau ? In "The tectonics of Turkey" (ed. E. Bozkurt), Geological Society, London, Special Publication, 173, 25-41.



Karakaya Kompleksi nedir?
Herhangi yeni bir litostratigrafi birimi tanımlanırken, bu birimin sağlam, ayrıntılı bir litoloji tanımının yapılması, altında ve üstünde yer alan birimlerin belirtilmesi, ve belki de en önemlisi birimin en iyi gözüktüğü tip ve referans kesit yerlerinin iyice tanımlanması gerekir. Maalesef Karakaya Kompleksi, 1975 senesinde Karakaya formasyonu olarak ilk defa tanımlandığında yukarıdaki işlemlerin hiç birisi sağlıklı olarak yapılmamıştır. Bingöl ve diğerleri (1975) Karakaya formasyonunun spilitik bazalt, çamurtaşları ve radyolaritlerle zaman zaman giriklik gösteren feldispatlı kumtaşı, kuvarsit, konglomera ve silttaşı ardalanmasından meydana geldiğini belirtmiş, ve formasyonun en iyi olarak Edremit, Zeytinli kuzeyi, Yenice Çal Karakolu-Derenti Köyü arasında görüldüğünü ifade etmekle yetinmiştir. Bingöl ve diğerleri (1975) ayrıca Karakaya formasyonunun yabancı (ekzotik) Permo-Karbonifer kireçtaşı blokları kapsadığını belirtmiş, ve Orta Triyas kireçtaşları ile örtüldüğünü ileri sürmüştür. Bingöl ve diğerleri (1975) Karakaya formasyonunun düşük dereceli net bir metamorfizma geçirdiğini belirtir. Önemli bir gözlem bu formasyonun tanımlandığı Biga yarımadasından doğuya Ankara'ya kadar izlenebildiğidir.

3. DOĞU PONTİDLERİN JEOLOJİSİ
Akın, H., 1978, Geologie, Magmatismus und Lagerstaettenbildung im ostpontischen Gebirge-Türkei aus der Sicht der Plattentektonik: Geologische Rundschau, v. 68, p. 253-283.

*Akıncı, Ö.T., 1984, The Eastern Pontide volcano-sedimentary belt and associated massive sulphide deposits, in J.E. Dixon and A.H.F. Robertson, eds., The Geological Evolution of the Eastern Mediterranean: Geological Society Special Publication, no. 17, p. 415-428.

Gedik, İ., Kırmacı, M.Z., Çapkınoğlu, Ş., Özer, E., Eren, M., 1996, Doğu Pontidlerin jeolojik gelişimi. Jeoloji Müh. Bölümü 30. Yıl Sempozyumu Bildirileri, 654-677.

Okay, A.I., 1984, Ağvanis metamorfitleri ve çevre kayalarının jeolojisi. Maden Tetkik ve Arama Enstitüsü Dergisi, 99/100, 51-71.

Okay, A.I. ve Leven, E.Ja., 1996, Stratigraphy and paleontology of the Upper Paleozoic sequence in the Pulur (Bayburt) region, Eastern Pontides. Turkish Journal of Earth Sciences, 5, 145-155.

Okay, A.I., Şahintürk, Ö., ve H. Yakar, 1997, Doğu Pontidlerde Pulur (Bayburt) bölgesinin stratigrafisi ve tektoniği. Maden Tetkik ve Arama Dergisi, 119, 1-22.



*Okay, A.I., ve Şahintürk, Ö., 1997, Geology of the Eastern Pontides. Regional and Petroleum Geology of the Black Sea and Surrounding Regions’de (editör: A. Robinson), American Association of Petroleum Geologists (AAPG) Memoir No. 68, 291-311.

Robinson, A.G., C.J. Banks, M.M. Rutherford, and J.P.P Hirst, 1995, Stratigraphic and structural development of the Eastern Pontides, Turkey: Journal of the Geological Society of London, v. 152, p. 861-872.

Yılmaz, Y., Tüysüz, O., Yiğitbaş, E., Can Genç, Ş., Şengör, A.M.C., 1997, Geology and tectonic evolution of the Pontides. Regional and Petroleum Geology of the Black Sea and Surrounding Regions’de (editör: A. Robinson), American Association of Petroleum Geologists (AAPG) Memoir No. 68, 183-226.

Zankl, H., 1962b, Magmatismus und Bauplan des Ostpontischen Gebirges im Querprofil des Harşit-Tales, NE Anatolien: Geologische Rundschau, v. 51, p. 218-239.



4. TAVŞANLI ZONU
Okay, A.I., 1981, Kuzeybatı Anadolu'daki ofiyolitlerin jeolojisi ve mavişist metamorfizması (Tavşanlı - Kütahya). (Geology and blueschist metamorphism of ophiolites in northwest Anatolia (Tavşanlı-Kütahya)). Türkiye Jeoloji Kurumu Bülteni, 24, 85-95.

Okay, A.I., 1984a, Distribution and characteristics of the northwest Turkish blueschists. In: The Geological Evolution of the Eastern Mediterranean (ed. J.E. Dixon and A.H.F. Robertson), Geological Society Special Publication No. 17, 455-466.

Okay, A.I., 1986, High pressure/low temperature metamorphic rocks of Turkey. In: Blueschists and Eclogites (ed. B.W. Evans and E.H. Brown), Geological Society of America Memoir No. 164, 333-348.

*Okay, A.I., 2009, Tavşanlı Zonu: Anatolid-Torid Bloku’nun dalma-batmaya uğramış kuzey ucu. Maden Tetkik ve Arama Bülteni (baskıda).

5. MENDERES MASİFİ VE BORNOVA FLİŞ ZONU
*Okay, A. ve Siyako, M., 1993, İzmir-Balıkesir arasında İzmir-Ankara Neo-Tetis Kenedinin yeni konumu. Türkiye ve Çevresinin Tektoniği-Petrol Potansiyeli (ed. S. Turgut) s. 333-355, Ozan Sungurlu Sempozyumu Bildirileri, Kasım 1991, Ankara.

*Okay, A.I., 2001, Stratigraphic and metamorphic inversions in the central Menderes Massif: a new structural model. International Journal of Earth Sciences (Geologische Rundschau), 89, 709-727.

*Şengör, A.M.C., Satır, M. & Akkök, R., 1984b, Timing of tectonic events in the Menderes massif, western Turkey: implications for tectonic evolution and evidence for Pan-African basement in Turkey: Tectonics, v. 3, p. 693-707.


6. KAZDAĞ MASİFİ VE EGE'DE GENİŞLEME TEKTONİĞİ
*Okay, A.I. & Satır, M., 2000, Coeval plutonism and metamorphism in a latest Oligocene metamorphic core complex in northwest Turkey. Geological Magazine, 137, 495-516.

Cavazza, W., Okay, A.I. & Zattin, M., 2008, Rapid early-middle Miocene exhumation of the Kazdag metamorphic core complex (Western Anatolia). International Journal of Earth Sciences (in press).

6. TÜRKİYE'NİN ÇEVRESİNDEKİ DENİZLER
Barka, A.A., Sakınç, M. & Yaltırak, C., 1999, Marmara Denizi'nin jeolojisi ve jeofiziği. Türkiye Denizlerinin ve Çevre Alanlarının Jeolojisi, N. Görür (editör), 131-210, TÜBİTAK, Ankara.

*Okay, A.I. & Okay, N., 1999, Doğu Akdeniz'in tektoniği. Türkiye Denizlerinin ve Çevre Alanlarının Jeolojisi, N. Görür (editör), 337-387, TÜBİTAK, Ankara.

*Okay, A.I. & Okay, N., 2007, Marmara Denizi’nin jeolojik durumu. “Bilimsel Açıdan Marmara Denizi” (editor M.L. Artüz), Türkiye Barolar Birliği yayınları, no. 119, Ofset Hazırlık, İstanbul, 29-59.

Yılmaz, Y., Genç, Ş.C., Gürer, Ö.F., Karacık, Z., Altunkaynak, Ş., Bozcu, M., Yılmaz, K., Elmas, A., 1999, Ege Denizi ve Ege bölgesinin jeolojisi ve evrimi. Türkiye Denizlerinin ve Çevre Alanlarının Jeolojisi, N. Görür (editör), 211-336, TÜBİTAK, Ankara.




7. GEOLOGY OF SOUTHEAST ANATOLIA

Autochthonous sequence of southeast Anatolia (Arabian Platform)
Most of the southeast Anatolia forms the northern margin of the Arabian Platform. During the Mesozoic and Tertiary the Arabian Platform was separated from the Anatolide-Tauride Block by the southern branch of the Neo-Tethys, which is today represented by the Bitlis-Zagros thrust front (Şengör and Yılmaz, 1981). The Arabian Platform is known to have a Pan-African crystalline basement overlain by a Palaeozoic to Tertiary sedimentary sequence. In most areas of the southeast Anatolia only the Cretaceous and younger deposits crop out on the surface. The lower parts of the sequence are exposed in a number anticlines (Rigo de Righi and Cortesini, 1964). These include the Amanos mountains west of Gaziantep, the Derik and Hazro anticlines south and north of Diyarbakır respectively, and the Zap anticlines south of Hakkari. Below I give an account of the stratigraphy of the Arabian Platform as exposed in the anticlines south of Hakkari.

The authochthonous sequence is well exposed in two faulted anticlines along the Zap River between Hakkari and Çukurca, the Great Zap anticline in the north and the Çukurca anticline in the south. The anticlines are major regional east-west trending structures with half wavelengths of 10-15 km, and extend along strike for over 100 km. Their southern margins are cut by thrust faults.

The Great Zap and Çukurca anticlines expose a thick sedimentary sequence from Early Cambrian to Eocene albeit with major gaps. The Cambrian to Carboniferous sequence is dominanted by clastic rocks, whereas the Permian to Eocene sequence is largely shallow marine carbonates.

The lowermost authochthonous sequences in the core of the Great Zap anticline are medium to thickly bedded sandstones and siltstones belonging to the Derik Group (ε1pε). The Derik Group in the Great Zap anticline has a minimum thickness of 611 m and based on scarce fossils is of Early Cambrian age (Perinçek, 1990; Yılmaz and Duran, 1997). Arenites of the Derik Group are conformably overlain by the Middle Cambrian dolomites and limestones of the Koruk Formation (ε2). The Koruk Formation, which is equivalent to the Çaltepe Limestone in the Taurides, is in turn overlain by yellowish brown siltstone, sandstone, shale intercalation of the Seydişehir Formation (ε3o) of Late Cambrian-Ordovician age. The Seydişehir Formation forms the core of the Çukurca anticline farther south.

The Seydişehir Formation is unconformably overlain by the strikingly variagated, thickly bedded quartzites of Upper Devonian age belonging to the Yığınlı Formation (d3). The Late Devonian age is based of fish fossils (Janvier et al., 1984). The quartzites show strong current bedding and have thin shale and siltstone interlayers, and have a measured thickness of 295 m. The quartzites of the Yığınlı Formation are conformably overlain by the shale, sandstone, sandy dolomite and limestone of the Köprülü Formation (d3c1). The Köprülü Formation straddles the Devonian-Carboniferous boundary (Perinçek, 1990; Yılmaz and Duran, 1997) and has a thickness of about 200 m.

The Upper Devonian-Lower Carboniferous Köprülü Formation is unconformably overlain by a thick carbonate sequence of Late Permian age. This Tanin Group (p2) has a thickness of nearly 1000 m, and consists of dark, bituminous, limestone and dolomitic limestone locally with chert nodules. A rich foraminfer fauna indicates the presence of all the Upper Permian stages from Murgabian to Dorashamian (Köylüoğlu and Altıner, 1989).

The dark Upper Permian carbonates are overlain by purple, green, yellow shale, siltstone, shaley limestone and limestone of Early Triassic age belonging to the Çığlı Group (t1). The Çığlı Group has a thickness of about 500 m, and is conformably overlain by the thickly bedded, neritic limestone and dolomite of the Cudi Group (t2k1) of Middle Triassic to Early Cretaceous age. The thickness of the Cudi Group increases from west to east, and in the Hakkari-Çukurca region is more than 1000 metres. The youngest ages from the Cudi Group are Aptian-Albian, however, in many regions the Lower Cretaceous sequence is eroded, and the Upper Cretaceous rests unconformably over the older formations (Perinçek, 1990).

In the northern margin of the Büyük Zap anticline the neritic carbonates of the Cudi Group are unconformably overlain by the shaley pelagic limestones of the Sayındere Formation (k2s), about 200 m thick. A rich pelagic foraminifera fauna in the limestones indicates a Campanian age for the Sayındere formation. The Sayındere Formation is unconformably overlain by the Campanian-Lower Paleocene sandstone, shale and marn of the Germav Formation (k2s). In several localities south of Hakkari, the Sayındere Formation is eroded and the Germav Formation rests directly on the neritic carbonates of the Cudi Group.

The Germav Formation is unconformably overlain by the Lower to Upper Eocene Midyat Group. The Midyat Group starts with red conglomerates and sandstones, and passes up into thinly to thickly bedded limestones locally with chert nodules and interlayers. The Midyat Group is tectonically overlain by the allochthonous Hakkari Complex along the frontal thrust. Slivers of Miocene continental sandstone, siltstone and mudstone (Şelmo Formation) indicates a Miocene and younger age for the thrusting (Perinçek, 1990).


Allochtonous units
Hakkari Complex
The Hakkari Complex covers large areas southeast of the Bitlis Massif between Narlı and Yüksekova, where it tectonically overlies the Eocene and Miocene formations of the autochthon. It is the time equivalent of the Maden Complex, which crops out widely farther west. The Hakkari Complex differs from the Maden Complex by the scarcity of the volcanic rocks. The Hakkari Complex is divided into two formations, a lower unit called Urşe Formation (e) and an upper melange type unit named as the Durankaya Complex (e1-2) (Perinçek, 1990, Yılmaz and Duran, 1997).
The Urşe Formation

The Urşe Formation consists predominantly of slightly metamorphosed siltstone, shale and fine-grained sandstone with limestone intercalations. The Urşe Formation is well exposed on the Başkale-Hakkari road, where it starts with fine grained metabasites and passes into a very thick slate series. Near Hakkari the slates are overlain by medium bedded dark carbonates. The aggregate thickness is more than 2000 metres. Pelagic and neritic foraminifera in the limestones indicates a Lower to Middle Eocene age for the Urşe Formation.


The Durankaya Complex

The Durankaya Complex lies tectonically over the Urşe Formation and consists of blocks of pelagic and neritic limestone, serpantinite, gabbro, basalt and amphibolite in a strongly deformed shale matrix. Some of the pelagic limestone "blocks" probably represent original limestone intercalations. Such limestones have yielded pelagic and neritic foraminifera of Early to Mid-Eocene age (Perinçek, 1990; Yılmaz and Duran, 1997). The thickness of the Durankaya Complex is believed to be over 2000 metres.



Maden Complex
The Maden Complex is the age equivalent of the Hakkari Complex in regions west of Narlı. It differs from the Hakkari Complex by the presence of abundant volcanic rocks. It crops out widely along the southern margin of the Bitlis Massif, as a tectonic slivers either directly under the Bitlis metamorphic rocks or through an intervening thrust sheet of the ophiolitic melange (Yüksekova Complex ).

The Maden Complex consists of sandstone, conglomerate, red pelagic limestone, basaltic lava, tuff. Limestone in the Maden Complex yield Lower to Middle Eocene foraminifera. In a few localities the Maden Complex is reported as lying unconformably over the Bitlis metamorphic rocks, however, in most places it is positioned between the Tertairy formations of the Arabian Platform and the Bitlis Massif. Yiğitbaş and Yılmaz (1996) regard the Maden Complex as products of a short-lived Mid-Eocene back arc basin, above the northward dipping subduction zone between the Arabian Platform and the Anatolide-Tauride Block as represented by the Bitlis Massif.

Around Baykan south of Bitlis the Maden Complex (locally named as the Baykan Complex by Göncüoğlu and Turhan, 1992) is lithologically highly varied. It ranges from a regular flysch sequence to an ophiolitic melange. It is difficult to put a boundary between the flyschoid Maden Complex and the overlying ophiolitic melange (Yüksekova Complex or the Guleman ophiolite).

Yüksekova Complex (Güleman ophiolite)
The Yüksekova Complex is the typical Upper Cretaceous ophiolitic melange with very wide outcrops in southeast Anatolia. In the Hakkari-Narlı region it forms large flat lying klippen over the Eocene aged Hakkari Complex, and is tectonically overlain by the Bitlis (Mordağ) metamorphic rocks. In the Bitlis-Baykan region the Yüksekova Complex forms tectonic slivers between the Bitlis metamorphic rocks and the underlying Maden Complex, and is locally called as the Güleman ophiolite (Göncüoğlu and Turhan, 1992), although it is more of an ophiolitic melange than a regular ophiolite.

The Yüksekova Complex has a melange like internal structure and represents a strongly deformed accretionary complex. It consists of a chaotic jumble of basalt, gabbro, serpentinite, pelagic limestone, radiolarian chert, neritic limestone, granodiorite, sandstone, siltstone, shale with an estimated vertical thickness of about 2000 metres. The youngest limestone blocks in the Yüksekova Complex give Coniacian-Campanian ages (Perinçek, 1990). The Yüksekova Complex is reported to be unconformably overlain by the Upper Palaeocene - Lower Eocene conglomerate, sandstone, siltstone, shale and limestone of the Seske Formation (Perinçek, 1990, Yılmaz and Duran, 1997).

Ophiolitic rocks also crop out north of the Bitlis Massif on the shores of Lake Van. This Gevaş "ophiolite" is of special importance as it lies directly under the Bitlis metamorphic rocks (Yılmaz et al., 1981), implying large scale allochthonity for the Bitlis Massif. The Gevaş "ophiolite" is a disordered ophiolite consisting of serpentinite, gabbro, basalt and limestone blocks. Some of the limestone blocks have yielded Maastrichtian rudists (Özer, 1992).,


Bitlis Massif
The Bitlis Massif forms an arcuate metamorphic belt, about 30 km wide and 500 km long, rimming the Arabian Platform in southeast Anatolia. It is separated from the Arabian Platform by a narrow belt of Upper Cretaceous to Eocene flysch and ophiolitic melange. The Bitlis Massif is generally considered as part of the Anatolide-Tauride Block, and was thus separated during the Mesozoic and Tertiary from the Arabian Platform by the southern branch of the Neo-Tethys.

Stratigraphically the Bitlis Massif is divided into two unit, representing the Preacanbrian basement and the overlying Phanerozoic sequence (Göncüoğlu and Turhan, 1984; Çağlayan et al., 1984). The Hizan Group, also called the Lower Unit, consists of gneiss, amphibolite, micaschist and eclogite. It probably represents the Pan-African and older basement of the Anatolide-Tauride Block. The Mutki Group, also called the Upper Unit, is made up of schist, phyllite, marble and metavolcanic rocks. It represents the metamorphosed Paleozoic-Mesozoic sequence of the Anatolide-Tauride Block. Granitic rocks and their apophyses intrude buth the basement and the cover sequence.


The Lower Unit (Hizan Group)

The Hizan Group is exposed widely from south of Lake Van to south of Bingöl for a distance of 250 km. It consists mainly of gneiss, amphibolite, eclogite and micaschist. Eclogites in various stages of preservation are only found north of Kulp (Okay et al., 1985), and recently in the Kesendere Valley north of Hizan. The Hizan Group is believed to have undergone two stages of metamorphism. A high-grade metamorphism of Precambrian age and a lower grade Late Cretaceous Alpide metamorphism.


The Upper Unit (Mutki Group)

The Mutki Group consists generally of metamorphosed platform type sedimentary rocks. The lower parts of the Mutki Group is made up of metaquartzite, phyllite, schist with rare calcschist and marble intercalations. The phyllites and micaschists are widely exposed between Hizan and Bahçesaray. The metaclastic rockp ass up into a carbonate rich sequence, in which Devonian and Upper Permian macro and microfossils have been described (Göncüoğlu and Turhan, 1983). The upper parts of the carbonates show a transition to phyllite, slate, metachert and metatuff. This Tütü Formation is believed to be of Upper Triassic age based on the presence of Involutina sp. in the transition zone south of Bitlis (Göncüoğlu and Turhan, 1983).


The Bitlis Massif is undergone a low to medium grade Alpide metamorphism. A single K/Ar age from the western part of the Bitlis Massif near Pütürge is 71.2 ± 3.6 Ma (Maastrichtian) (Hempton, 1985).
Granitoids

Leucocratic granitoids have wide exposures north of Hizan, north of Mutki and southwest of Muş. They generally intrude the Hizan Group but are not affected by the Pre-Cambrian regional metamorphism. Rb/Sr and K/Ar white mica ages from the Muş granite are Late Cretaceous (73-107 Ma) (Göncüoğlu, 1984).


Kırkgeçit Formation
The Kırkgeçit Formation occupies large areas southeast of Van, where it lies unconformably over the Bitlis metamorphic rocks, Yüksekova Complex and the Hakkari Complex. It consists of siliciclastic turbidites with extensive olistostrome horizons (Perinçek, 1990). Scarce fossils indicate a Late Eocene to Early Miocene age for the Kırkgeçit Formation. Post-Miocene tectonics has resulted in imbrication of the Kırkgeçit Formation with the underlying units.

Some References
Boray, A., 1975, Bitlis dolayının yapısı ve metamorfizması. TJK Bülteni, 18, 81-84.

Çağlayan, M.A., İnal, R.N., Şengün, M., Yurtsever, A., 1984, Structural setting of the Bitlis Massif. In "Geology of the Taurus Belt", O. Tekeli and M.C. Göncüoğlu (eds.), Proceedings of the Int. Symp. on the Geology of the Taurus Belt, 26-29.9.1983, Ankara, 245-254.

Göncüoğlu, M.C., 1984, Muş-Kızılağaç metagranitinin başkalaşımı ve yaşı. MTA dergisi, 99/100, 72-83.

Göncüoğlu, M.C., and Turhan, N., 1983, Bitlis metamorfitlerinde yeni yaş bulguları. MTA Ens. Dergisi, 95/96, 44-49.

Göncüoğlu, M.C., and Turhan, N., 1984, Geology of the Bitlis metamorphic belt. In "Geology of the Taurus Belt", O. Tekeli and M.C. Göncüoğlu (eds.), Proccedings of the Int. Symp. on the Geology of the Taurus Belt, 26-29.9.1983, Ankara, 237-244.

Göncüoğlu, M.C., and Turhan, N., 1992, Muş - İ33 paftası. 100 000 scale geological map series of Turkey, Maden Tetkik ve Arama Genel Müdürlüğü, Ankara.

Görür, N., Çelikdemir, E. and Dülger, S., 1991, Carbonate platforms developed on passive continental margins: Cretaceous Mardin carbonates in SE Anatolia as an example. İTÜ Bulletin, 44, 301-324.

Hall, R., 1976, Ophiolite emplacement and the evolution of the Taurus suture zone, southeastern Turkey. Geol. Soc. Am. Bull., 87, 1078-1088.

Hall, R., and Mason, R., 1972, A tectonic melange from the Eastern Taurus Mountains, Turkey. J. Geol. Soc. London, 128, 395-397.

Helvacı, C., and Griffin, W.L., 1984, Rb-Sr geochronology of the Bitlis Massif, Avnik (Bingöl) area, S.E. Turkey. In: The Geological Evolution of the Eastern Mediterranean (ed. J.E. Dixon and A.H.F. Robertson), Geological Society Special Publication No. 17, 403-413.

Hempton, M.R., 1985, Structure and deformation history of the Bitlis suture near Lake Hazar, southeastern Turkey. Geol. Soc. Am. Bull., 96, 233-243.

Ketin, İ., 1980, Hakkari-Çukurca arasının büyük Zap suyu boyunca jeoloji kesiti. In "Altınlı Symposium" , 11-13, Ankara.

Köylüoğlu M. & Altıner D. (1989) - Micropaléontologie (Foraminiféres) et biostratigraphie du Permien Supérieur de la région d'Hakkari (SE Turquie). Rev. Paléobiologie, v. 8, pp. 467-503, Genéve.

Okay, A., Arman, M.B., and Göncüoğlu, M.C., 1985, Petrology and phase relations of the kyanite-eclogites from Eastern Turkey: Contrib. Mineral. Petrol., 91, 196-204.

Özer, S., 1992, Presence of rudist bearing limestone blocks derived from the Arabian Platform in Gevaş (Van) ophiolite. Maden Tetkik ve Arama Dergisi, 114, 75-82.

Özkaya, İ., 1982, Marginal basin ophiolites at Oramar and Karadağ, SE Turkey. J. Geol. Soc. Lond., 139, 203-210.

Perinçek, D., 1979, Guidebook for Excursion "B", Interrelations of the Arab and Anatolian plates. 1st Geol. Congr. Middle Eastr, Ankara, 34 pp., 4-7.9.1979. p

Perinçek, D., 1990, Hakkari ili ve dolayının stratigrafisi, Güneydoğu Anadolu, Türkiye. Türkiye Petrol Jeologları Derneği Bülteni, 2, 21-68.

Rigo de Righi, M., and Cortesini, A., 1964, Gravity tectonics in foothills structure belt of southeast Turkey. AAPG Bull., 48, 1911-1937.

Şengün, M., 1993, Bitlis Masifi'nin metamorfizması ve örtü çekirdek ilişkisi. Maden Tetkik ve Arama Dergisi, 115, 1-13.

Yılmaz, E., and Duran, O., 1997, Güneydoğu Anadolu Bölgesi otokton ve allokton birimler stratigrafi adlama kılavuzu "Lexicon". Türkiye Petrolleri A.O. Araştırma Merkezi grubu Başkanlığı, Eğitim Yayınları No. 31, 460 p.

Yılmaz, Y., 1978, Gevaş (Van) dolayında Bitlis Masifi/Ofiyolit ilişkisi. Türkiye. 4. Petrol Kongresi Bildiriler Kitabı, 83-93.



*Yılmaz, Y., 1993, New evidence and model on the evolution of the southeast Anatolian orogen. Bull. Geol. Soc. Am., 105, 252-271.

Yiğitbaş, E., and Yılmaz, Y., 1996, New evidence and solution to the Maden complex controversy of the Southeast Anatolian orogenic belt (Tırkey). Geol. Rundschau, 85, 250-263.



Compiled by Aral Okay - October 2003





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