In western Anatolia, to the south of the & Idot;zmir-Ankara Suture, the Menderes Massif, Cycladic Blueschists, Afyon Zone, and Bornova M & eacute;lange form the main tectonic belts from bottom to top structurally. In the Akhisar region, the Akhisar Nappe consists of the Hask & ouml;y Formation below and the G & ouml;renez Limestone above. The Hask & ouml;y Formation is composed of a metaclastic sequence with metarhyolite intercalations (237.4 +/- 1.1 Ma, zircon LA-ICP-MS) and recrystallized limestone lenses, and it gradually passes upward into Late Norian-Early Jurassic G & ouml;renez Limestone. New radiogenic data from metarhyolites of the Hask & ouml;y Formation and fossil determinations from recrystallized limestones of the G & ouml;renez Limestone show that the age of the Akhisar Nappe ranges from early Late Triassic to Early Jurassic. Along the contact between the Akhisar Nappe and the Menderes Massif, the linear fabric and associated asymmetric structures in the mylonitic fault zone indicate a top-NE shear sense. Correlation between the internal stratigraphy of the Akhisar Nappe and the Mesozoic part of the Afyon Zone sequences in its eastern part indicates that the Akhisar Nappe is the western continuation of the Afyon Zone.

In the vicinity of the ancient city of Lebedos, known as one of the twelve Ionian cities, located south of Izmir in W. Anatolia (Turkiye), the NE-SW-trending active Tuzla Fault zone is characterized by numerous hot springs and associated travertine-type carbonate deposits (sinter). Among these, the active Doganbey bath features an approximately 560 m-long hot water aqueduct, called the "Roman Aqueduct". This structure is distinct from the well-known Roman (Byzantine) ruins (Karakoc bath) in the area in terms of its materials and construction techniques. Despite the absence of detailed archaeological or geochronological studies in this region, the Doganbey bath and aqueduct have conventionally been attributed to the Roman era. The trough and sidewalls of the Doganbey aqueduct are covered with a 5-25 cm-thick, laminated sinter crust, formed by the flow of hot water. Each sinter lamina comprises radial structures of calcite and/or aragonite, resembling feather-like shrub structures. This study employs the U-Th chronometry to determine the age of sinter layers covering the Doganbey bath aqueduct. Two layers from a single sinter sample of the ancient Doganbey aqueduct yielded U-Th ages of 2717 +/- 106 and 2528 +/- 106 years (BP). These dates indicate a pre-Roman phase of settlement in the Lebedos area, a finding documented for the first time through this study.

A complete section of the Bitlis Massif crops out in the Avnik and unaldi regions (E Turkiye). It comprises a core of Precambrian-Early Cambrian gneisses, mafic metavolcanic rocks with Kiruna-type magnetite-apatite ores and metagranite bodies. Unconformably overlying this core is a cover succession made up of Silurian to late Cretaceous micaschists and marbles. The Kiruna-type ore beds, focused on this paper, range from centimetres up to 20 m in thickness and are concordantly interbedded with mafic metalavas, detrital magnetite-rich metavolcanoclastic rocks, and metachert beds. Geological characteristics of the metamorphosed ore-bearing volcanic and volcanosedimentary succession indicate that the magnetite-apatite ores were formed in a shallow marine environment by volcanic exhalative and sedimentary processes. U-Pb zircon ages obtained from the interlayered basaltic flows are 578 - 542 Ma, marking the maximum age of ore formation. Geological and petrological characteristics of the basaltic association in the Precambrian units indicate that their formation took place in a forearc environment along the northern margin of Gondwana. This active magmatic margin was formed above the south dipping Prototethys oceanic crust, which was carrying a small oceanic or continental fragment. When this microcontinent collided with Gondwana, south-verging compressional deformation, high-grade regional metamorphism, and syntectonic intrusion of the Avnik and Yayla metagranites occurred. U-Pb zircon ages of 521- 506 and 521- 503 Ma for the Avnik and Yayla metagranites, respectively, date this collision, and thus the termination of ore deposition in the Bitlis Massif.

Figure. Photomicrographs showing the low-grade metamorphosed volcanic textural features of metarhyolites in the Afyon Zone where the intrusive boundary of the Alacam granite stock is observed with metarhyolites. a, b) Slightly deformed volcanic texture with subhedral embayed quartz phenocrystals (Q) in recrystallized glassy matrix is characteristic for the metarhyolites of the Afyon Zone

The Kazdağı Massif was previously considered as the metamorphic basement of the Sakarya Zone, a microcontinental fragment in NW Anatolia. Our new field mapping, geochemical investigations, and radiometric dating lead to a re-evaluation of previous suggested models of the massif. The Kazdağı metamorphic succession is subdivided into two major units separated by a pronounced unconformity. The lower unit (the Tozlu metaophiolite) is a typical oceanic crust assemblage consisting of ultramafic rocks and cumulate gabbros. It is unconformably overlain by a thick platform sequence of the upper group (the Sarıkız unit). The basement ophiolites and overlying platform strata were subjected to a single stage of high-temperature metamorphism under progressive compression during the Alpine orogeny, accompanied by migmatitic metagranite emplacement. Radiometric age data obtained from the Kazdağı metamorphic succession reveal a wide range of ages. Metagranites of the Kazdağı metamorphic succession define a U–Pb discordia upper intercept age of ca. 230 Ma and a lower intercept age of 24.8 ± 4.6 Ma. This younger age agrees with 207Pb/206Pb single-zircon evaporation ages of 28.2 ± 4.1 to 26 ± 5.6 Ma. Moreover, a lower intercept age of 28 ± 10 Ma from a leucocratic metagranite supports the Alpine ages of the massif within error limits. Reconnaissance detrital zircon ages constrain a wide range of possible transport and deposition ages of the metasediments in the Sarıkız unit from ca. 120 to 420 Ma. Following high-temperature metamorphism and metagranite emplacement, the Kazdağı sequence was internally imbricated by Alpine compression, and the lowermost Tozlu ophiolite thrust southward onto the Sarıkız unit. Field mapping, internal stratigraphy, and new radiometric age data show that the Sarıkız unit is the metamorphic equivalent of the Mesozoic platform succession of the Sakarya Zone. The underlying metaophiolites are remnants of the Palaeo tethys Ocean, which closed during the early Alpine orogeny. After strong deformation attending nappe emplacement, the unmetamorphosed Miocene Evciler and Kavlaklar granites intruded the tectonic packages of the Kazdağı Massif. During Pleistocene time, the Kazdağı Massif was elevated by EW trending high-angle normal faults dipping to Edremit Gulf, and attained its present structural and topographic position. Tectonic imbrication, erosion and younger E–W-trending faulting were the main cause of the exhumation of the massif.

The Sindirgi District (Balikesir, western Turkey) lies within the Western Anatolian volcanic and extensional province, adjacent to the WNW-trending Simav graben, approximately 130 km NE of Izmir. The Sindirgi mining district is underlain mainly by Miocene volcanic rocks and hosts several low-sulfidation epithermal Au-Ag deposits and prospects located near the towns of Sindirgi and Bigadic. The Kiziltepe low-sulfidation epithermal gold-silver deposit is located southeast of Yusufcam village (Sindirgi, Balikesir), and other prospects, including the Kepez, Kavakliduz, and Karaduz prospects, are located northeast of Kiziltepe. Potentially economic grades occur at Kiziltepe, which contains a measured and indicated resource of 1.754.790 Mt @3.0 g/t Au, 44 g/t Ag, hosted by quartz veins showing colloform/crustiform banding, quartz pseudomorphs after bladed calcite, and multiphase brecciations, all typical textures noted in low-sulfidation epithermal deposits. Alteration minerals include mixed-layer illite/smectite, high-crystallinity illite, and kandite group minerals (dickite and nacrite). Precious metal minerals include traces of electrum, acanthite, Au-rich acanthite, and Ag-Hg-Au-Tl-Pb series, occurring mainly within quartz. Pyrite is the most common opaque mineral at Kiziltepe. 40Ar/39Ar dating of adularia from the quartz veins indicates an age of mineralization of 18.3 ± 0.2 Ma. The ore mineralization is divided into three main phases. These comprise the deposition of: coarse-grained quartz, illite, pyrite, and minor precious metals (Phase I); major gold–silver-bearing medium-grained quartz, which commonly exhibits crustiform banding, carbonate replacement, and hydrothermal breccia textures (Phase II); and fine-grained chalcedonic quartz with colloform/crustiform banding (Phase III). Phase II is economically the most important in terms of precious metal content. Phase II quartz contains fluid inclusions, which range from predominantly vapor-rich to predominantly liquid-rich with homogenization temperatures (Th) varying from 157 to 330 °C, showing a cluster between 190 and 300 °C, and ice-melting temperatures (Tm) ranging from -0.2 to -2.9 °C (salinity from 0.5-4.8 wt.% NaCl equiv.). Moderate to strong positive correlations occur between Au-Ag (R = 0.8) and Au-Cu (R = 0.5), whereas there is no correlation between As and Au or Ag.

Understanding the ages and emplacement mechanism of the gneissic granites cropping out in large areas of the Menderes Massif has a critical importance in its tectonic evolution. Based on some radiogenic age data, the gneissic granites and the surrounding high-grade micaschists have been advocated to be the Precambrian "Core Succession" that was undergone high-grade metamorphism during the Pan-African Orogenesis. The micascists and marbles of Palaezoic-Mesozoic age have been defined as the "Cover Succession" unconformably overlying the core assemblages. It has also been indicated that during the Alpine Orogenesis and by the Main Menderes Metamorphism the core and cover successions were metamorphosed together in relatively lower grade conditions. Although the Menderes succession underlies a large region in the western Anatolia and display uncovered outcrops, in nowhere structural evidences of the unconformity between Pan-African core and the Palaeozoic-Mesozoic cover series has been reported. It is very difficult to expect the Alpine Orogeny to erase the older Pan-African structures to a point of undefinable state. In this study, we have new mapped and examined the boundary relations between the so-called Pre-Cambrian core and PalaeozoicMesozoic country succession around Dibek Mountain, Çine-Yataðan and Ýncirliova Dam site. In Dibek Mountain gneissic granites were emplaced, as migmatitic fronts, into the marble lenses-bearing micaschists paralel to their foliation planes. Along the Çine-Yataðan road, migmatitic syn-tectonic granitic fronts injected into and engulfed the Palaeozoic black marble, black chert and micaschist alternation. In this region, the Palaeozoic units pass upward into the Triassic metadetritals with mafic volcanic intervals and they in turn grade into the Mesozoic platform-type marble succession. In this location the granites intrude into the Palaezoic and Mesozoic series which were paleontologically dated in some other areas of the masif. Similarly around the Ýncirliova Dam site the augen gneisse-migmatitic granite complex intruded into a complete stratigraphic section from Palaeozoic to Triassic and the Mesosozic marble succession. New field data indicate that the high-temperature-type Barrowien Main Menderes Metamorphism caused a rejuvenation in the crust and granites with large migmatitic fronts emplaced syntectonically into the entire section of the masif from thick metadetrital units below and the PalaeozoicMesozoic cower series above. Precambrian and Alpine zircon ages determined from the gneissic granites could be explained by the rejuvenation and migmatism during the Main Menderes Metamorphism.

During and after the closure of the Neo-Tethyan Ocean and progressive collision of the Tauride-Anatolide Platform with the Sakarya Continent, widespread magmatism occurred in NW Anatolia. This magmatism is manifested in a NW-trending belt along the northern border of the Menderes Massif. Due to the complex geodynamic setting of this region, the exact emplacement depth of the granitoids is still a matter of debate. Here we present Al-in-hornblende barometrical data and Sr-Nd-Pb isotope compositions of the Early Miocene Alacam granite. The results imply a shallow emplacement depth of this granite (4.7 +/- 1.6 km) in contrast to previous studies which suggested emplacement along the brittle-ductile boundary of the crust. Furthermore, an evaluation of literature data let us reconsider the general emplacement mechanism of the Alacam and other Early Miocene granitoids in the region. Initial isotopic signatures of the Alacam granite are Sr-87/Sr-86(I)=0.70865-0.70915, e(Nd)(I)= -5.8 to -6.4, delta O-18=9.5-10.5, (206)pb/Pb-204 isotope ratios vary between 18.87 and 18.90. These features indicate an assimilation-dominated crustal crystallization and melt derivation from an older middle crustal protolith.

Most of the age determinations and their interpretations in the Menderes Massif were or are still used to evidence the geodynamic nature of the region with its bordered paleogeography. Last 20 years, nearly, most of the age data in the massif conflict with the well-known stratigraphical and lithological features and still preserve its debate. Moreover, individual age techniques were not properly interpreted or performed within their parameters (closure temperatures, related mineral equilibrium, metamorphic conditions. . . etc.). Particularly, most popular age determination methods of 40Ar/39Ar mistakenly interpreted as cooling ages instead of neo-crystallization ages. Similarly, Rb-Sr mica ages could easily demonstrate open chemical behavior related to the fluid interactions and present the timing of last fluid circulation events instead of cooling ages. The age data obtained from massif were interpreted without any consideration of the widespread Oligo-Miocene magmatic activity in the northern Menderes Massif, Neogene volcanism, and graben structures in western Anatolia. This study aims to present and summarize new (U-Pb-ID, 207Pb-206Pb single zircon evaporation, Rb-Sr mica) and previously obtained age data from northern and southern Menderes Massif in comparison with literature to better understanding of the age interpretations within their geological limits and related mineral features. Our results in comparison with previously published age data in their detailed stratigraphical features indicate that obtained youngest ages (c.20-25 Ma), which were previously interpreted as the cooling of the massif, are still questionable, and they are more likely representing the timing of fluid circulation events and/or resetting of their related isotopic systems.

During the Alpine orogeny, the northern margin of the Tauride-Anatolide Block was deeply buried below the Sakarya continent and subjected to high pressure/low temperature metamorphism. Along this suture zone Tavsanli Zone, Afyon Zone, Bornova Flysch Zone and opholitic melange nappes form the different tectono-stratigraphic units. The Afyon Zone, in its western part, consists of a slightly deformed and metamorphosed Mesozoic platform succession with abundant fossil remains. The lower part of this succession is represented by the Ikibasli Formation which is dominated by the metadetrital units consisting of rhyolitic to basaltic volcanic intervals and large limestone blocks. A platform-type carbonate sequence (Budagan limestone) forms the upper part of the Afyon Zone. From the Ikibash Formation and the Budagan limestone unit, a Late Triassic to Maim fossil assemblage was identified constraining the depositional age of the platform carbonates and the age of rhyolitic volcanism accompanying the deposition. Geochemical characteristics of the rhyolites indicate a continental crust origin of the magma.The depositional site of the Ikibasli Formation was a tectonically active extensional basin in which rhyolitic and basaltic volcanic activity occurred. This extension along the northern Menderes Massif coincides with the spreading of a branch of the Neotethyan ocean in NW Anatolia. The age and facies characteristics of the Mesozoic carbonate succession of the Afyon Zone resemble those described from various parts of the Tauride-Anatolide Block indicating that they once belonged to the same large platform.

Menderes Masifi' nin cok genis bolumlerinde yuzeyleyen gnaysik granitlerin yerlesim yaslari ve mekanizmalarinin belirlenmesi, masifin tektonik evriminin anlasilmasi acisindan kritik onem tasir. Bircok arastirici bu gnayslardan elde ettikleri radyojenik zirkon yaslarina dayanarak granitlerin ve yuksek dereceli mikasistlerden olusan yan kayalarinin Menderes Masifi' nin Prekambriyen yasli Cekirdegi oldugunu ve Pan-Afrikan orojenezi sirasinda yuksek dereceli metamorfizma gecirdigini savunur. Mikasist ve mermerlerden olusan PaleozoyikMesozoyik yasli Ortu olarak tanimlanmis istifin uyumsuz olarak ortmus oldugu belirtilir. Alpin orojenezi sirasindaki Ana Menderes Metamorfizmasi sirasinda Cekirdek ve Ortu birlikte fakat daha dusuk dereceli metamorfizmaya ugradigi ileri surulur. Menderes Masifi kayalari Bati Anadolu'da cok genis ve acik mostralar sunmasina ragmen Pan-Afrikan cekirdek ile ortu birimleri arasinda olmasi beklenen acisal diskordansin yapisal verileri hicbir yerde acik olarak saptanamamistir. Alpin olaylarinin Pan-Afrikan yapilarini tamamen silmis olmasi aciklanmasi zor bir sorun olarak durmaktadir. Bu calismada Menderes Masifi'nde Prekambriyen yasli cekirdek olarak tanimlanan gnaysik granitler ile Paleozoyik-Mesozoyik cevre kayalarin iliskisi Dibekdagi, Cine-Yatagan yolu ve Incirliova Baraji alanlarinda yeniden haritalanarak incelenmistir. Dibekdagi alaninda gnaysik granitler cevre kayalarin foliasyonu boyunca migmatitik cepheler seklinde mermer mercekleri iceren mikasistlerin icine yerlesmistir. Sistlerden granitlerin icerisine dogru cevre kayalar derece derece ozumlenir ve kuvarso-feldspatik mercekler ve girdiler artarak magmatik cephenin icine girilir. Cine-Yatagan Yolu boyunca migmatitik sintektonik granitik cephe, masifin Paleozoyik yasli siyah mermer, siyah cort ve sist ardalanmasini yutarak yerlesmistir. Bu alanda Paleozoyik birimler stratigrafik olarak uste dogru Triyas yasli mafik volkanik ara katkili kirintili birimlere ve onlar da Mesozoyik platform mermerlerine gecer. Bu alanda yaslari masifin baska bolgelerinde fosillerle belirlenmis ve fasiyesleri iyi bilinen Paleozoyik-Mesozoyik ortu birimleri gnaysik granitler tarafindan yutulmustur. Benzer sekilde, Incirliova baraj alaninda gozlu gnays-migmatitik granit kompleksi Paleozoyik yasli siyah cort ve mermer istifini ve onlarin uzerine gelen Triyas metakirintili kayalarini ve en ustte Mesozoyik beyaz mermer istifinin tumunu keser. Yeni saha verileri yuksek sicaklik trendine sahip Barroviyen tipi Ana Menderes Metamorfizmasi' nin kabukta rejuvenasyona neden oldugunu ve migmatitik cepheler seklinde yukselen sintektonik granitlerin olustugunu ve bunlarin hem cekirdek-ortu sinirini hem de Paleozoyik-Mesozoyik ortu birimlerini yutarak yerlestigini gosterir. Masifteki gnaysik granitlerden yaygin olarak elde edilen Prekambriyen ve yer yer ise Alpin yaslari bu tur bir rejuvenasyon ve migmatitlesme ile aciklanabilir.

Menderes Masifi' nin çok geniş bölümlerinde yüzeyleyen gnaysik granitlerin yerleşim yaşları ve mekanizmalarının belirlenmesi, masifin tektonik evriminin anlaşılması açısından kritik önem taşır. Birçok araştırıcı bu gnayslardan elde ettikleri radyojenik zirkon yaşlarına dayanarak granitlerin ve yüksek dereceli mikaşistlerden oluşan yan kayalarının Menderes Masifi' nin Prekambriyen yaşlı "Çekirdeği" olduğunu ve Pan-Afrikan orojenezi sırasında yüksek dereceli metamorfizma geçirdiğini savunur. Mikaşist ve mermerlerden oluşan PaleozoyikMesozoyik yaşlı "Örtü birimleri" olarak tanımlanmış istifin "çekirdek birimlerini" uyumsuz olarak örtmüş olduğu belirtilir. Alpin orojenezi sırasındaki Ana Menderes Metamorfizması sırasında "Çekirdek" ve "Örtü birimleri" birlikte fakat daha düşük dereceli metamorfizmaya uğradığı ileri sürülür. Menderes Masifi kayaları Batı Anadolu'da çok geniş ve açık mostralar sunmasına rağmen Pan-Afrikan çekirdek ile örtü birimleri arasında olması beklenen açısal diskordansın yapısal verileri hiçbir yerde açık olarak saptanamamıştır. Alpin olaylarının Pan-Afrikan yapılarını tamamen silmiş olması açıklanması zor bir sorun olarak durmaktadır. Bu çalışmada Menderes Masifi'nde Prekambriyen yaşlı çekirdek olarak tanımlanan gnaysik granitler ile Paleozoyik-Mesozoyik çevre kayaların ilişkisi Dibekdağı, Çine-Yatağan yolu ve Incirliova Barajı alanlarında yeniden haritalanarak incelenmiştir. Dibekdağı alanında gnaysik granitler çevre kayaların foliasyonu boyunca migmatitik cepheler şeklinde mermer mercekleri içeren mikaşistlerin içine yerleşmiştir. Şistlerden granitlerin içerisine doğru çevre kayalar derece derece özümlenir ve kuvarso-feldspatik mercekler ve girdiler artarak magmatik cephenin içine girilir. Çine-Yatağan Yolu boyunca migmatitik sintektonik granitik cephe, masifin Paleozoyik yaşlı siyah mermer, siyah çört ve şist ardalanmasını yutarak yerleşmiştir. Bu alanda Paleozoyik birimler stratigrafik olarak üste doğru Triyas yaşlı mafik volkanik ara katkılı kırıntılı birimlere ve onlar da Mesozoyik platform mermerlerine geçer. Bu alanda yaşları masifin başka bölgelerinde fosillerle belirlenmiş ve fasiyesleri iyi bilinen Paleozoyik-Mesozoyik örtü birimleri gnaysik granitler tarafından yutulmuştur. Benzer şekilde, Incirliova baraj alanında gözlü gnays-migmatitik granit kompleksi Paleozoyik yaşlı siyah çört ve mermer istifini ve onların üzerine gelen Triyas metakırıntılı kayalarını ve en üstte Mesozoyik beyaz mermer istifinin tümünü keser. Yeni saha verileri yüksek sıcaklık trendine sahip Barroviyen tipi Ana Menderes Metamorfizması' nın kabukta rejüvenasyona neden olduğunu ve migmatitik cepheler şeklinde yükselen sintektonik granitlerin oluştuğunu ve bunların hem çekirdek-örtü sınırını hem de Paleozoyik-Mesozoyik örtü birimlerini yutarak yerleştiğini gösterir. Masifteki gnaysik granitlerden yaygın olarak elde edilen Prekambriyen ve yer yer ise Alpin yaşları bu tür bir rejüvenasyon ve migmatitleşme ile açıklanabilir.

The Alacam region of NW Turkey lies within the Alpine collision zone between the Sakarya continent and the Menderes platform. Four different tectonic zones of these two continents form imbricated nappe packages (including the Afyon zone), intruded by the Alacam granite. Newly determined U-Pb zircon ages of this granite are 20.0 +/- 1.4 and 20.3 +/- 3.3 Ma, indicating early Miocene emplacement. Rb-Sr biotite ages of the granite are 20.01 +/- 0.20 and 20.17 +/- 0.20 Ma, suggesting fast cooling at a shallow crustal level. Geochemical characteristics show that the Alacam granite is similar to numerous EW-trending plutons in NW Anatolia. Gneissic granites of the Afyon tectonic zone were intruded by the Miocene Alacam granite and have been interpreted in earlier studies as sheared parts of the Alacam granite, which formed along a crustal-scale detachment zone under an extensional regime. We determined a U-Pb zircon age of 314.9 +/- 2.7 Ma for a gneissic granite sample of the Afyon zone, demonstrating that these rocks are unrelated to the Miocene Alacam granite. The early Miocene granitic plutons bear post-collisional geochemical features and are interpreted as products of Alpine-type magmatism along the Izmir-Ankara suture zone in NW Turkey, and seem to have no genetic relation to the detachment zone.

(1) Technical Vocational School of Higher Education, Dokuz Eylul University, Izmir-Torbali, Turkey (altug.hasozbek@deu.edu.tr), (2) Institut fur Geowissenschaften, Universitat Tubingen,Germany (altug.hasozbek@deu.edu.tr) (satir@uni-tuebingen.de) (wolfgang.siebel@uni-tuebingen.de), (3) Dokuz Eylul University, Engineering Faculty, Geology Engineering, Izmir-Tinaztepe, Turkey (burhan.erdogan@deu.edu.tr) (erhan.akay@deu.edu.tr), (4) Hacettepe University, Department of Geological Engineering, Ankara, Turkey (gdeniz@hacettepe@deu.edu.tr), (5) University Blaise Pascal, OPGC, Lab. Magmas et Volcans, , Clermont-Ferrand Cedex, France (gdeniz@hacettepe.edu.tr)

The northern border of the Menderes Massif is dominated by gneiss-schist-marble association and meta-granites. The high-grade units of the massif are tectonically overlain by a meta-platform sequence of the Afyon Zone and the Cretaceous-early Tertiary HP/LT Tavsanli Zone. The Simav Magmatic Complex, comprising the shallow-seated, I-type, calc-alkaline, post-collisional Egrigoz and Koyunoba granites, and associated subvolcanic-volcanic sequences crosscuts the Menderes Massif, Afyon Zone and tectonic contact between them.In this paper, the age relation between gneisses, metagranites of the Menderes Massif and the Egrigoz and Koyunoba granites was evaluated by isotope dating. Pb-207/Pb-206 evaporation ages between 607 and 501 Ma and U-Pb zircon ages of 543 +/- 10 and 30.04 +/- 0.56 Ma were obtained for two gneiss samples and a metagranite in the Menderes Massif, respectively. U-Pb zircon analyses yield crystallization ages of 21.7 +/- 1.0 Ma for the Koyunoba granite and 19.4 +/- 4.4 Ma for the Egrigoz granite. A cooling age of 18.77 +/- 0.19 Ma for the Egrigoz granite was obtained by Rb-Sr (whole rock, biotite) analyses. Field occurrences, geochemical characteristics and geochronological data obtained from the Egrigoz and Koyunoba granites show close similarities with other Oligo-Miocene granitoids in northwestern Anatolia indicating that they emplaced along an E-W trending regional magmatic belt and are not individual bodies related to local, north-dipping, low-angle detachment faults as suggested in previous papers. (C) 2010 Elsevier Ltd. All rights reserved.

In the northwestern part of Anatolia along the Izmir-Ankara Suture Zone, the Kazda˘ g and Uluda˘ g meta- morphic massifs form an E-W trending belt between the Sakarya Continent in the north and the Menderes Massif in the south. Internal succession of these two massifs have been described as metamorphic complexes consisting of various kinds of micaschists, quartz mica schist, gneisses, amphibolites and marbles. In the Kazda˘ g metamorphics,