Gültekin Topuz

Istanbul Technical University · Eurasia Institute of Earth Sciences

Avalonia, a large composite terrane, extends from the northeastern regions of America and Canada to southern Britain and Belgium/Netherlands, continuing on to Poland. It was accreted to Laurentia and Baltica during early Paleozoic. The late Neoproterozoic basement of the Istanbul Zone (NW Turkey), which is considered the far-east extension of Avalo...

Subduction initiation in oceans is key to understanding regional and global plate tectonics and ocean basin dynamics; however, its genetic mechanism is still enigmatic. The most famous model that predicts intraoceanic subduction initiation along transform faults or fracture zones (i.e., the Subduction Initiation Rule) has been widely used to explai...

The paradigm of plate tectonics holds that ocean plates are rigid during drift and only experience tectonic deformation at subduction zones, but new findings from the Pacific challenge this idea. Geological and geophysical evidence from the Ontong Java, Shatsky, Hess, and Manihiki oceanic plateaux indicates that extensional deformation during plate...

The obituary of Professor Aral Okay, published by the Geological Society of America.

Within the Tethyan belt, the NW-Iranian block is bound by two sutures, the Sevan-Akera suture in the north, and the Zagros suture in the south, where the pre-Cambrian geology is poorly constrained. Lower-Middle Cambrian sandstone in NW Iran is represented by quartz and feldspar dominated sub-arkose and sub-litharenite with well-developed cross bedd...

Geochemical and geochronologic data are presented for meta-mafic to meta-felsic rocks along the Paleo-Tethys Suture in the Binalood Mountains east of Neyshabur, NE Iran. The rocks have a late Cambrian age (U–Pb zircon, ~ 490 Ma) and were metamorphosed in the Early Jurassic ( ⁴⁰ Ar/ ³⁹ Ar amphibole and plagioclase, 199–192 Ma). The rocks of this sui...

The Sakarya Zone (northern Turkey) is characterized by the emplacement of voluminous granitoids during the late Carboniferous. In this study, we present geological, U-Pb zircon age, elemental abundance and Sr-Nd-Pb isotopic data on two highly evolved Carboniferous granite bodies within the Early to Late Jurassic volcaniclastic rocks in the Şiran re...

The Sakarya Zone of northern Turkey contains a well-preserved Early–Middle Jurassic and Late Cretaceous submarine magmatic arc constructed over pre-Jurassic bedrocks that are considered to be the eastward extension of the Armorican Terrane Assemblage in Europe. In this study, we present U-Pb-Hf isotopic data from the detrital zircons of middle Perm...

During the Late Cretaceous, a magmatic arc extended from the Lesser Caucasus through the northern margin of the Pontides into Srednogorie, Timok, Banat, and Apuseni (ABTS) in the Balkans for a distance of 2700 km. We studied the arc volcanic rocks in three regions in the Western Pontides and reviewed the geological data on the Lesser Caucasus-Ponti...

The Istanbul Zone (NW Turkey) forms the eastward extension of Avalonia and was subjected to deformation, uplift and erosion for a time period of 40–50 Ma following the collision with the Sakarya Zone during Early to Late Carboniferous. This paper deals with the petrology and age of the volumetrically minor basic and acidic volcanism at the lowermos...

Abstract: The Eastern Anatolian Plateau (EAP), approximately 2000 m above sea level, is located between the Eastern Pontides to the north, the Arabian Platform to the south, and the Iranian Plateau to the east. It is characterized by approximately 6 km-thick Maastrichtian to Quaternary volcano-sedimentary cover which unconformably overlies continen...

The Eastern Anatolian Plateau (EAP), approximately 2000 m above sea level, is located between the Eastern Pontides to the north, the Arabian Platform to the south, and the Iranian Plateau to the east. It is characterized by approximately 6 km-thick Maastrichtian to Quaternary volcano-sedimentary cover which unconformably overlies continental and oc...

This study deals with the age and petrogenesis of mafic-ultramafic intrusions ranging in size from a few meters to 10 km within the Early Carboniferous high-grade gneisses of the Pulur Complex in the Eastern Pontides. The intrusions comprise dunite, wehrlite, gabbronorite, leucogabbro, anorthosite and ilmenite-bearing gabbronorite of cumulus origin...

Placer ore deposits are forming by the transport and accumulation of heavy minerals with a density above the average density of 2.9 g/cm3. Key factors in the formation of placer deposits are the presence of an ore source area and its distance to the accumulation place, tectonic activity controlling erosion, drainage network, and climatic conditions...

The Late Cretaceous accretionary complexes along the İzmir-Ankara-Erzincan (IAE) Neo-Tethyan suture zone in northern Turkey record the subduction–accretion processes of the oceanic lithosphere ranging in age from the Late Triassic to the Late Cretaceous. These accretionary complexes contain fragments of Early and Middle Jurassic metamorphic and non...

A 3000-km long magmatic belt of predominantly Eocene age extends from Anatolia into Iran representing a major magmatic flare-up. We present new zircon UPb, Ar/Ar mica and apatite fission-track ages for this magmatism from northwestern Turkey, and review its geochemistry and geodynamic setting. The new age data show that magmatism started at the Lat...

Ophiolitic mélanges in Anatolia represent Mesozoic subduction-accretion complexes, which are unusually poor in land-derived coarse-clastic rocks. A segment of the ophiolitic mélange in the Beynam region south of Ankara was studied. The ophiolitic mélange consists of three accretionary units (AUs), which are distinguished by lithology, structure, ag...

Middle Permian bimodal volcanic rocks exposed in the Kocaeli Peninsula represent the first igneous event in the entire Paleozoic record of the Istanbul Zone together with coeval acidic intrusions reported from other parts of the zone. These volcanic rocks crop out as intercalations at the lower horizons of Permian-Earliest Triassic fluvial sediment...

Middle Permian bimodal volcanic rocks exposed in the Kocaeli Peninsula document the first igneous activity in the entire Paleozoic history of the Istanbul Zone together with coeval acidic intrusions reported from other parts of the zone. These volcanic rocks occur as intercalations within Permian-Earliest Triassic fluvial sedimentary rocks and main...

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The Intra‐Pontide Suture between the Istanbul and Sakarya zones was regarded debatably either as a Neotethyan Suture or a trace of the Rheic Suture in Turkey. Here, we present U‐Pb ages and Lu‐Hf isotopic compositions of detrital zircons from the Silurian to Triassic sandstones of the Istanbul Zone. Upper Silurian‐Lower Devonian sandstone is domina...

Plate tectonics is a well-recognized and accepted theory that provides rather simple explanations to many geodynamics problems. The theory depends on rifting and drifting continental plates, creating new oceanic lithosphere along the mid-ocean ridges which later sinks into the asthenosphere along the convergent subduction plate boundaries. Oceanic...

Terranes are passengers within drifting oceanic plate, and ride with the plate to subduction plate boundaries. Although oceanic lithosphere readily subducts into the mantle at the plate boundary, terranes may resist sinking or not, depending on a variety of controlling factors that are not very well understood. Further, the tectonic development of...

Terranes are passengers within drifting oceanic plate, and ride with the plate to subduction plate boundaries. Although oceanic lithosphere readily subducts into the mantle at the plate boundary, terranes may resist sinking or not, depending on a variety of controlling factors that are not very well understood. Further, the tectonic development of...

The Cadomian belt (ca. 600–500 Ma) extends from North America through Europe to Iran (Figure 1). It is characterized mainly by eroded, metamorphosed, and deformed magmatic arcs and back-arc basins developed along the northern margin of Greater Gondwana or Pannotia during Late Ediacaran to Early Cambrian time (e.g. Murphy et al. 2002; Stern 2008; Li...

Terrane accretion is a ubiquitous process of plate tectonics that delivers fragments of subduction-resistant lithosphere into a subduction zone, resulting in events such as ocean plateau docking or continental assembly and orogenesis. The post-collisional extension of continental terranes is a well-documented tectonic process linked with gravitatio...

İzmir-Ankara-Erzincan suture zone contains several metamorphic and non-metamorphic ophiolitic rocks ranging in age from Late Triassic to Late Cretaceous. The Jurassic supra-subduction zone (SSZ) ophiolitic and metamorphic rocks are commonly observed in the Late Cretaceous Tekelidağ mélange, which is located at the eastern part of the İAE suture zon...

Lawsonite is an important mineral for understanding seismic anisotropy in subducting oceanic crust due to its large elastic anisotropy and prevalence in cold subduction zones. However, there is insufficient knowledge of how lawsonite twinning affects seismic anisotropy, despite previous studies demonstrating the presence of twins in lawsonite. This...

Apatite fission-track and (U-Th)/He ages from Carboniferous to Eocene siliciclastic rocks of the Istanbul Zone (NW Turkey) range from 220 to 46 Ma, and from 46 to 18 Ma, respectively. Apatite grains from the upper Cretaceous and Eocene volcaniclastic and siliciclastic formations yielded unreset fission-track ages (85 to 65 Ma), whereas the Lower Cr...

The Anatolide-Tauride block in the Tethyan belt represented passive northern continental margin of Gondwana throughout Paleozoic time. In this paper, we report on a relatively large amphibolite-facies metaquartz-syenite to -granite complex (~ 60 km2) in the Eastern Anatolia, the easternmost part of the Anatolide-Tauride block. Igneous textures in t...

The Anatolide-Tauride block in the Tethyan belt represented passive northern continental margin of Gondwana throughout Paleozoic time. In this paper, we report on a relatively large amphibolite-facies metaquartz-syenite to -granite complex (~ 60 km2) in the Eastern Anatolia, the easternmost part of the Anatolide-Tauride block. Igneous textures in t...

Apatite fission-track and (U-Th)/He ages from Carboniferous to Eocene siliciclastic rocks of the Istanbul Zone (NW Turkey) range from 220 to 46 Ma, and from 46 to 18 Ma, respectively. Apatite grains from the upper Cretaceous and Eocene volcaniclastic and siliciclastic formations yielded unreset fission-track ages (85 to 65 Ma), whereas the Lower Cr...

Stratigraphic evidence is used to interpret that the East Anatolian Plateau with 2 km average elevation today was below sea level ~20 Ma and uplift began in the northern part. The presence of voluminous volcanic rocks/melt production across the plateau—younging to the south—corroborates geophysical interpretations (e.g., high heat flow and lower se...

Ophiolite assemblages of the South Tianshan fold-and-thrust-belt (STS) track the seafloor dynamics of the late Cambrian to Carboniferous Turkestan Ocean in the western Central Asian Orogenic Belt. We interpret new geochronological and geochemical data for the Mailisu ophiolite from western Kyrgyzstan as evidence for an early Silurian incipient subd...

Full text (free access): https://www.sciencedirect.com/science/article/pii/S1674987119300295 We present new, geological, metamorphic, geochemical and geochronological data on the East Anatolian – Lesser Caucasus ophiolites. These data are used in combination with a synthesis of previous data and numerical modelling to unravel the tectonic emplacem...

The Early Miocene high-K I-type plutonic rocks constitute the early products of the Neogene to Qua-ternary magmatism, and the youngest exposed intrusions in the East Anatolian plateau. Here we deal with the petrogenesis of the Early Miocene Tas¸lıçayTas¸Tas¸lıçay intrusion covering an area of ~62 km 2. The intrusion comprises leucogranite, and mino...

The Sakarya Zone (northern Turkey) is a Gondwana-derived continental block accreted to northern Laurussia during the Carboniferous, and is regarded as the eastward extension of Armorica. Timing of its detachment from the northern margin of Gondwana, thus opening of the Paleo-Tethys, is poorly known. Here, we report on metagranite and amphibolite wi...

The Sakarya Zone (northern Turkey) is a Gondwana-derived continental block accreted to northern Laurussia during the Carboniferous, and is regarded as the eastward extension of Armorica. Timing of its detachment from the northern margin of Gondwana, thus opening of the Paleo-Tethys, is poorly known. Here, we report on metagranite and amphibolite wi...

The Ekmekçi granodiorite porphyry is a member of the E-W trending, post-collisional Eocene magmatic rocks of the northern Anatolia. It occurs as a relatively small stock, but represents a link between the plutonic and the volcanic rocks. This Early Eocene granodiorite porphyry is intruded into the Upper Triassic rocks of the Karakaya complex of the...

Late Paleocene adakitic granitoids are rare in Iran except in the northwest. We focused on the adakitic Saqqez-Takab pluton, which occupies an area of ~600 km². New U-Pb zircon dating yield crystallization ages of 58–56 Ma (Thanetian). These granitoids comprises granite, quartz monzonite and monzogranite with granular to mylonitic textures. They ha...

The Mamu Dağı ophiolite, ca. 13 km long and 5 km across (Tokat, Sakarya Zone), consists of peridotites, pyroxenites, gabbros, and basalts, which are crosscut by dolerite dykes. These rocks show variable degrees of serpentinization and alteration. Gabbroic rocks consisting of plagioclase + clinopyroxene ± orthopyroxene ± olivine ± amphibole ± sphene...

Eruption of (74-26 ka old) pyroclastic (pumice fall) flow deposits of the Quaternary Gölcük volcano, Isparta, SW Turkey, carried a cargo of Western Anatolian’s youngest monzonitic-syenitic ejecta, 40Ar-39Ar hornblende ages range 313+64 - 268+43 ka, and indicate that a shallow level felsic plutonic complex existed underneath the crater. These ejecta...

The mafic-ultramafic Fariman complex in northeastern Iran has been interpreted as a Paleo-Tethyan ophiolitic fragment with subduction- and plume-related characteristics as well as a basin deposit on an active continental margin. Contributing to this issue, we present geochemical, geochronological, and mineralogical data for transitional and tholeii...

The late Cretaceous accretionary complex along the İzmir–Ankara–Erzincan suture zone, northern Turkey, includes various types of metamorphic rock together with radiolarite, sandstone, mudstone, serpentinite, basalt and limestone. Metaplagiogranite blocks (up to 5 m in diameter) and a meta-gabbro slice (800 × 500 m) cross-cut by meta-plagiogranite a...

Yüksek basınç metamorfik kayaları Biga Yarımadası’nın güney kesiminde bulunan Çetmi Melanjı içerisinde tektonik bir dilim olarak bulunmaktadır. Çetmi Melanjı içerisindeki yüksek basınç kayaları eklojit ve bunlara eşlik eden granat-mika şistlerden oluşmaktadır. Granat-mika şistler içerisindeki detritik rutillerin Cr ve Nb içerikleri sırasıyla 355-10...

The volcanic rocks are widely exposed in the study area which located in the İzmir-Ankara-Erzincan suture (IAES) zone. In this study, we present petrogenetic features of the volcanic rocks and a new age data from radiolarites located in the accretionary complexes from the Çamlıbel (South of Tokat) and the Kızıldağ (North of Sivas) regions. The vo...

The Eastern Mediterranean region within the Tethyan belt is characterised by two main pulses of suprasubduction-zone ophiolite formation during the Early-Middle Jurassic and Late Cretaceous. Despite vast exposures of the Permo-Triassic accretionary complexes, related suprasubduction-zone ophiolites and the timing of subduction initiation leading to...

The Tethyan belt in the eastern Mediterranean region is characterized by the accretion of several micro-continental blocks (e.g. Anatolide-Tauride, Sakarya and Istanbul terranes). The accretion of a micro-continental block to the active continental margin and subsequent initiation of a new subduction are of crucial importance in understanding the g...

In northwest Turkey, high-pressure metamorphic rocks occur as exotic blocks within the Çetmi mélange located on the south of the Biga Peninsula. Rutile chemistry and rutile thermometry obtained from the eclogite and associated garnet-mica schist in the Çetmi mélange indicate significant trace element behaviour of subducted oceanic crust and source-...

The East Anatolian plateau (Turkey) is extensively covered by Neogene to Quaternary volcanic-sedimentary rocks, and is characterized by an attenuated lithospheric mantle. Its pre-Neogene basement is commonly considered to consist entirely of Late Cretaceous to Oligocene oceanic accretionary complexes, formed at the junction of several continental b...

İzmir-Ankara-Erzincan Kenet Zonu'nu (Kuzey Türkiye) oluşturan yığışım karmaşıkları çeşitli tür ve fasiyeste metamorfik kayaçlar içerir. Tokat güneyinde meta-gabroları kesen meta-plajiyogranitler, deforme serpantinit, çamurtaşı ve radyolaryalı çörtlerin oluşturduğu bir matriksle beraber yığışım karmaşığı içinde tektonik olarak yer alırlar. Hem meta-...

High pressure-low temperature eclogite-facies rocks are commonly regarded to represent the exhumed fragments of subducted slabs. High pressure-low temperature metamorphic rocks representing the remnants of oceanic crust are exposed on the Lower Cretaceous Çetmi ophiolitic accretionary complex, located in the southern part of the Biga Peninsula. The...

Stratigraphic evidence from the Murat region (Mus-Van basins) suggests that the east Anatolian plateau emerged from below sea level ~ 13-15 Ma. The plateau stands at 2 km average elevation today and is underlain by hot/buoyant asthenospheric mantle rather than thick lithosphere. The voluminous melt production/magmatism during the last 13 Myrs is in...

Two Gondwana-derived Paleozoic belts rim the Archean/Paleoproterozoic nucleus of the East European Platform in the Black Sea region. In the north is a belt of Paleozoic passive-margin-type sedimentary rocks, which extends from Moesia to the Istanbul Zone and to parts of the Scythian Platform (the MOIS Block). This belt constituted the south-facing...

This paper deals with the petrogenesis of two-mica granites within the amphibolite-facies metamorphic rocks in the Uludağ Massif (NW Turkey). The two-mica granites are represented by three different types (i) a 17 km long and 1.5 km-wide strongly foliated and lineated metagranite, (ii) a relatively younger circular granite, 11 km by 6.5 km, free of...

Numerous (meta-)gabbroic dikes or stocks occur within the latest Neoproterozoic- early Cambrian series of the Menderes Massif (Anatolide-Tauride Block, western Turkey). These well-preserved rocks were locally converted into eclogitic metagabbros and garnet amphibolites along the contacts or shear zones. Both bulk-rock composition and compositions o...

The Late Cretaceous accretionary complex of the İzmir–Ankara–Erzincan suture zone, near Artova, is composed mainly of peridotites (variably serpentinized), amphibolite, garnet-micaschist, calc-schist, marble, basalt, sandstones, neritic limestones. The metamorphic rocks were interpreted as the metamorphic sole rocks occurring at the base of mantle...

The ˙ Izmir-Ankara-Erzincan suture zone in northern Turkey is one of the major tectonic zones separating the Pon-tides to the North from the Anatolide-Tauride block and Kı r¸sehirr¸sehir Massif to the South. The accretionary complex of the ˙ Izmir-Ankara-Erzincan suture zone, near Artova, is composed mainly of peridotites with varying degree serpen...

The Early-Middle Jurassic SSZ type dismembered ophiolite sequence, which is remnants of the Tethyan oceanic lithosphere, crop out in the accretionary complex around Tokat-Çamlıbel region (Northern Turkey). The main lithology of the ophiolite sequence are cumulate gabbros, isotropic gabbros and basalts. The amphibolite layers, which their thickness...

The east Anatolian orogenic plateau is characterized by an average elevation of 2 km, and is delimited by the Bitlis-Zagros collision zone to the south and the Pontide arc to the north. Stratigraphic evidence suggests that the high plateau attained its current elevation since the Serravallian (about 12 million years ago), but probably did not reach...

The metamorphic rocks having different ages and various metamorphic facies are located as blocks and tectonic slices in the Late Cretaceous accretionary complex (İzmir-Ankara-Erzincan suture zone) in Northern Sivas. The 40Ar/39Ar dating method on amphibole, muscovite and phengite from metamorphic rocks yielded different ages ranging from Middle-Upp...

The Kızılırmak accretionary complex near Kargı is tectonically bounded by the Jurassic and Early Cretaceous metamorphic massives of the Central Pontides. It consists mainly of serpentinite, serpentinized peridotite, gabbro, basalt, metabasite and deep-marine sedimentary rocks. The metabasites in the Kızılırmak accretionary complex are tectonically...