Eastern Taurides Research Articles

Devonian shallow-water sequences from the North Gondwana coastal margin (Central and Eastern Taurides, Turkey): Sedimentology, facies and global events

Turkey is an integral part of the Alpine–Himalayan orogenic belt with a number of tectonostratigraphic units striking in an E–W direction. These belts consist of terranes of different tectonic settings, ranging from oceanic basins to active and passive continental margins. The age of incorporated units of continental margin origin ranges from the Cambrian to the Cenozoic, and includes unmetamorphosed to low-grade Devonian rocks in the Pontides, Taurides and on the Arabian Plate. This paper describes the detailed sedimentology, facies and biostratigraphy of three 900 to 1200 m thick Devonian successions in the Central and Eastern Taurides (Eceli, Halevikdere and Kocadere). During the Devonian, the Central and Eastern Taurides were situated at the northern margin of Gondwana. The sediments described were deposited on this margin in coastal to shelf environments. Despite similar large-scale trends, regional differences in the sedimentary sequences can be distinguished, especially for the lower part of the Devonian. For the first time, sufficient biostratigraphical data have been recovered to allow the successions to be subdivided at a stage scale, permitting their approximate correlation and comparison with the regional lithostratigraphy. The temporal development of sedimentary processes, facies changes, and hinterland signatures recorded in the individual sections have been reconstructed, allowing their correspondence to global events to be recognized and discussed for the first time. The palaeobiogeographic distribution of various organisms within these succession suggests a comparatively narrow sea (‘Rheic Ocean’) between Laurasia and Gondwana/Peri-Gondwana during the Devonian.

Trace Element Geochemistry of the Jurassic Coals in the Feke and Kozan (Adana) Areas, Eastern Taurides, Turkey

In this study, trace element and organic matter-trace element relation between Jurassic coals exposed in three different fields in the eastern Taurides were examined and their enrichment values with respect to upper crust values were calculated and the coal characteristics were also compared with world arithmetic means and those from the U.S. In comparison to the Feke and Kızılinç coals, Pb, Zn, Ag, and Hg element contents of the Gedikli coals are considerably high; Ni, As, and Ge contents are moderately high; and Cr, Cu, Co, Cd, Sb, Ga, and Sn contents are slightly high. The element concentrations are very similar to those of other fields. In the Gedikli coals, Sr content is extremely low and Ba content is slightly low with respect to other fields. Re, Mo, U, V, and B element concentrations are different for each of three fields. The major element contents of the Feke, Gedikli, and Kızılinç coals were correlated with world arithmetic means and average values of coals from the U.S. and Fe, K, Mg, and Na concentrations were found to be similar. Ti and Al contents of the world and USA coals are higher while Ca and Mn concentrations are lower. Considering trace element contents of the world and U.S. coals, Ba is considerably high, Cu and Zr are moderately high, and Ga, Rb, and Sc elements are slightly high. In comparison to world arithmetic means and U.S. coals, Sr content of the Feke and Kızılinç coals are very high while those of the Gedikli coals are lower. For major and trace elements, factors of enrichment with respect to upper crust values were also calculated. The highest enrichment values were calculated for Ca and S. Except for Se and Rb, all other trace elements are enriched with respect to upper crust.

First record of Crassostrea cyathula Lamarck 1806 from �the Rupelian-Lower Chattian of Sarıbuğday-Kovancılar� (NE Palu) Eastern Taurids, E Turkey

Crassostrea cyathula (Lamarck 1806), a valuable biostratigraphic marker, was found for the first time in eastern Turkey (Eastern Mediterranean), in the Rupelian-Lower Chattian sedimentary sequences of northeastern Palu, Elazığ region, and its palaeoecological characters, palaeobiogeographic and stratigraphic distribution are discussed. These oyster specimens are also the first abundant macrofossils from the Oligocene sediments of the Sarıbuğday-Kovancılar section, which were formerly only recorded by micropalaeontological data.

Andean-type active margin formation in the eastern Taurides: Geochemical and geochronogical evidence from the Baskil granitoid (Elazığ, SE Turkey)

The Southeast Anatolian Orogen resulted from collision of the Afro-Arabian and the Eurasian plates following the Cretaceous to Miocene closure of the southern Neotethyan oceanic basin. In this orogenic belt, there are number of tectonomagmatic/stratigraphic units in the Kahramanmaraş–Malatya–Elazığ region that are important to understand the geological evolution of southeast Anatolia during the Late Cretaceous. These are (a) metamorphic massifs (i.e. Malatya–Keban platform), (b) ophiolites (i.e. Göksun, İspendere, Kömürhan), (c) ophiolite-related metamorphics (i.e. Berit metaophiolite) and (d) granitoids (i.e. Göksun, Doğanşehir and Baskil). The Baskil granitoid crops out to the northwest of Elazığ and is a large magmatic body (170 km 2) that intruded all of the above-mentioned units during Late Cretaceous time. The Baskil granitoid comprises both mafic and felsic plutonic/sub-plutonic rock associations. The felsic plutonic phase includes granite, granodiorite, tonalite and quartz monzonite whereas the felsic sub-plutonic phase is characterized by aplite, granophyre, granite porphyry and granodiorite porphyry. The granite and granodiorite contain mafic microgranular enclaves (MME). The mafic plutonic phase comprises gabbro, diorite, quartz diorite, whereas the mafic sub-plutonic phase is represented by diabase, microdiorite, quartz microdiorite, diorite porphyry, quartz diorite porphyry and dykes of orbicular gabbro dyke. Geochemically, the Baskil granitoid rocks have I-type, metaluminous-peraluminous calc-alkaline characteristics. The REE- and ocean ridge granite-normalized multi-element patterns and tectonomagmatic discrimination diagrams, together with biotite geochemistry suggest that the granitoids were formed in a volcanic arc setting. The 40Ar/ 39Ar geochronology of the granitoid rocks yielded biotite ages of 81.9 ± 0.7 Ma and 81.5 ± 0.8 Ma (95% confidence level). Coexisting hornblende, and hornblende from additional samples, yielded ages ranging from 84.0 ± 0.7 Ma to 81.5 ± 1.1 Ma. The ophiolites are believed to have formed in a suprasubduction zone tectonic setting, whereas the ophiolite-related metamorphic rocks formed either during the initiation of intraoceanic subduction or later-stage thrusting (∼ 90 Ma). These units were then thrust beneath the Malatya–Keban platform during the progressive closure of the southern Neotethys. This was followed by intrusion of the granitoids (85–82 Ma) along the Tauride active continental margin of the southern Neotethys.

Application of the Crosta technique for alteration mapping of granitoidic rocks using ETM+ data: case study from eastern Tauride belt (SE Turkey)

The present study particularly focuses on the determination of alteration products of the granitoid associations by remote sensing techniques. Widespread magmatism has occurred in the Malatya‐Elazığ area of the eastern Tauride belt in south east Turkey as a consequence of plate convergence and continental collision. The development of the magmatism in the study area can be subdivided into two separate phases, the Baskil and the Bilaser Tepe complexes. Based on the petrographic and bulk‐rock geochemical data, the Baskil granitoids are classified as quartz‐diorite, quartz‐monzodiorite and tonalite, whereas the Bilaser Tepe granitoids are classified as granodiorite and dacite‐porphyry. Both the Baskil and Bilaser Tepe granitoids have peraluminous and metaluminous compositions. The Crosta method is found to be very useful for enhancing the altered areas with hydroxyl and iron oxide minerals. The Crosta method is applied to six (1, 2, 3, 4, 5 and 7) and two sets of four (1, 3, 4, 5 and 1, 4, 5, 7) bands of ETM+ data. However, the areas with potassic, phyllic, argillic and propylitic alteration zones are enhanced much better by using six bands of Landsat 7 ETM+ data. The alteration differences of these two magmatic groups are also tested with the Crosta technique using four band combinations. Although no distinct difference is observed on the hydroxyl image, a clear difference is observed between the two magmatites on the iron oxide image. The present study shows that the Crosta technique is not only generating hydroxyl and iron oxide images, but also differentiates between two magmatite groups of different ages and genesis.

MIDDLE CARNIAN (LATE TRIASSIC) NASSELLARIA (RADIOLARIA) OF KÖSEYAHYA NAPPE FROM EASTERN TAURIDES, EASTERN TURKEY

Abundant, very diverse, and well-preserved Nassellarian fauna has been obtained from cherty/clayey limestone levels at the basal part of the Koseyahya nappe east of the town of Elbistan, Eastern Taurides. A comparison with the radiolarian faunas of Austria, Japan and Turkey allows us to assign a middle Carnian age to this radiolarian fauna from the Elbistan region. This fauna contains Nassellaria that are typical for this time interval. Moreover, it contains Tetraporobrachia haeckeli Kozur & Mostler which is an index fossil that gives the name to the zone established by Kozur & Mostler. As a result of the taxonomic study of the Nassellarian fauna, thirty-nine taxa among which nine new species ( Goestlingella tueysuezi, Haeckelicyrtium planum, Hinedorcus koeseyahyaensis, Katroma ? ornata, K. ? proba, K. ? tunoglui, Syringocapsa firma, S. nuda, Sanfilippoella carterae ) and twelve taxa remained in open nomenclature are described and figured in this study.

Metamorphic sole rocks and their mafic dykes in the eastern Tauride belt ophiolites (southern Turkey): implications for OIB-type magma generation following slab break-off

The metamorphic sole rocks observed between the Pozantı–Karsantı ophiolite and the melange unit are located on the eastern part of the Tauride carbonate platform. They consist of ortho-amphibolites at the top and metasedimentary lithologies at the base. Amphibolites from the metamorphic sole rocks are represented by OIB, MORB and IAT based on their major, trace and REE compositions. The isolated dolerite dykes intrude both the metamorphic sole rocks and the ophiolitic unit at different structural levels. The dolerite dykes cutting the metamorphic sole rocks are enriched in LILE and depleted in HFSE. Enrichment in LILE such as Th, relative to HFSE, is indicative of the presence of a subduction component. Flat-lying REE patterns of the dolerite dykes also confirm an IAT source. Pyroxenite and albitite dykes also cut the metamorphic sole rocks. REE patterns of pyroxenite dykes show prominent LREE enrichment, similar to that observed in within-plate alkaline basalts. The alkaline isolated pyroxenite dykes were probably the result of late-stage magmatism fed by melts that originated from an OIB source, shortly before the emplacement of the Pozantı–Karsantı ophiolite onto the Tauride carbonate platform. A hydrothermal alteration stage is characterized by albitite formation in the joints of the metamorphic sole rocks and by secondary mineralization along the contact zones of dolerite dykes. Mineral parageneses in the metamorphic sole rocks exhibit amphibolite and greenschist-facies assemblages. Geothermobarometric studies based on a newly recognized mineral assemblage (e.g. kyanite) and chemical compositions of minerals in the metamorphic sole rocks indicate that the metamorphic temperature during the metamorphism was 570–580°C and the pressure was around 5–6 kbar.

Fusulinid Foraminifera of the Bashkirian–Moscovian boundary in the eastern Taurides, southern Turkey

Abstract. Fusulinid faunas of the Pennsylvanian (Bashkirian–Moscovian) deposits of the Siyah Aladag Nappe were investigated from the Kuzuoluk section located in the eastern Taurides. The section is represented by grey, occasionally laminated, algal and fusulinid-rich limestones. The foraminiferal faunas of the Kuzuoluk section are very diverse and abundant which allows identification of the Bashkirian–Moscovian boundary by index-species such as Verella spicata and Aljutovella aljutovica. Other key taxa in the Bashkirian–Moscovian interval include Pseudostaffella grandis and Staffellaeformes staffellaeformis (Bashkirian Stage, upper part of the Lower Substage), Ozawainella pararhomboidalis and Staffellaeformes bona (Bashkirian Stage, Upper Substage), Verella spicata (Bashkirian Stage, Upper Substage) and Aljutovella aljutovica Zones (Moscovian Stage, Lower Substage). The Bashkirian–Moscovian microfaunas from the Kuzuoluk section can be correlated with assemblages from Tien-Shan, the Southern Urals and the Russian Platform.

Late Viséan foraminifers and algae from the Cataloturan Nappe, Aladag Mountains, eastern Taurides, southern Turkey

The Aladag Mountains at the western end of the eastern Taurides, southern Turkey, are composed of nappe structures imbricated in the Late Cretaceous by ophiolite emplacement. The Cataloturan Nappe contains Mississippian (i.e., Early Carboniferous) deep-water (basinal-lower slope) facies in the lower part and shallow-water (shelf edge) facies in the upper part. These Mississippian strata belong to the Nohutluk Formation. The main outcrop occurs at Nohutluktepe where it is 460 m thick. Eighty taxa of algae, foraminifers, and calcareous microproblematica permit dividing the upper part of the formation into three informal assemblage biozones: (1) Howchinia bradyana longa – Lituotubella magna – Koktjubina (?) sp. biozone (late Viséan Cf6γ1), (2) Bradyina rotula – Euxinita tauridiana biozone (Cf6γ2), (3) Janischewskina typica – Biseriella aff. parva biozone (upper Cf6δ). The genus Euxinita is discussed and a new species E. tauridiana nov. sp. is described. A paleobiogeography, based on Euxinita, Koktjubina (?), Vissarionovella, Janischewskina and Hortonella, is reconstructed, where the Taurides are juxtaposed to the northwestern border of the Paleotethys, with possible direct connections with Russia, Kazakhstan, western Europe, and Morocco.

Hybridization of mafic microgranular enclaves: mineral and whole-rock chemistry evidence from the Karamadazı Granitoid, Central Turkey

On the Eastern Tauride Belt, the Cretaceous calc-alkaline Karamadazi Granitoid consists of quartz diorite containing mafic microgranular enclaves (MME) and leucocratic granite. The quartz diorite consists of plagioclase (An8-65), hornblende, biotite, K-feldspar, quartz, epidote and titanite. Subrounded MME in the quartz diorite are holocrystalline, fine-grained, quartz diorite to diorite in composition, and display a similar mineral assemblage to their host. Large crystals in MME and quartz diorite show various disequilibrium microstructures indicative of hybridization. Plagioclase crystals exhibit inverse, normal, and oscillatory zoning with maximum core-to-rim An content increase up to 38% in the enclave and 40% in the quartz diorite. Both hornblende and augite exhibit normal and reverse zoning even in the same sample. The new field, textural, mineral compositional, and geochemical evidence leads to the conclusion that MME could have formed through injection of successive pulses of basic magma into upward mobile magma chambers containing cooler, partially crystalline quartz diorite magma. The quartz diorites show similarity to high-Al TTG (tonalites–trondhjemites–granodiorites), with their high Na2O, Sr, LREE, and low Mg#, Cr, HREE contents, and are suggested to be produced by extensive interaction between the crustal and mantle-derived melts through mixing at depth. In contrast, leucogranites have geochemical characteristics distinct from the quartz diorites and MME, and are probably not involved in MME genesis.

Geological and Geochemical Characteristics of Granitoids in the Eastern Tauride Belt, Southeastern Turkey

As a consequence of plate convergence and continental collision, widespread magmatism occurred in the Malatya-Elazig area of the eastern Tauride belt. Igneous activities in the study area can be subdivided into two separate phases, the Baskil and Bilaser Tepe complexes. The present study particularly focuses on these granitoid associations. The Late Cretaceous granitoid associations exhibit calc-alkaline and tholeiitic major-oxide trends. Baskil granitoids consist primarily of quartz, plagioclase, and hornblende, with relatively lesser amounts of orthoclase. Bilaser Tepe granitoids are mainly composed of quartz, orthoclase, plagioclase, hornblende, and biotite. Oxides and apatite are common accessory phenocrysts in both granitoids. Based on petrographic and bulk-rock geochemical data, Baskil granitoids are classified as quartz-diorite, quartz-monzodiorite, and tonalite, whereas Bilaser Tepe granitoids are granodiorite and tonalite. Both units have peraluminous and metaluminous compositions. Trace-element plots indicate that the Baskil granitoids have geochemical features similar to I-type granitoids derived from island-arc settings. The Bilaser Tepe granitoids exhibit both I- and S-type characteristics, suggesting a post-collisional origin. Baskil magmatism is interpreted as arc magmatism related to Late Cretaceous convergence between the Keban microcontinent and the southern branch of Neo-tethys. This magmatic phase was followed by collision between the Keban microcontinent and the Bitlis-Pütürge massif. Continental collision resulted in crustal thickening. Subsequently, the Bilaser Tepe granitoids were intruded, signifying post-collisional tectonic setting in the Malatya-Elazig area. Consequently, the petrological and geochemical data are consistent with the geodynamic model of the eastern Taurus.

Effect of weathering on the geomechanical properties of the Miocene basalts in Malatya, Eastern Turkey

Miocene volcanic rocks are widely exposed in the eastern Taurids, Turkey. The geomechanical properties and weathering degree of the Middle–Upper Miocene basalts were determined at the Boztepe dam site in Malatya, eastern Turkey. An engineering geology map of the Boztepe dam site was made and the joint sets and the degree of weathering determined in the field. The degree of weathering and RQD values were obtained on some 1,195 m of core which was then compared with a series of geomechanical tests including unit weight, porosity, water absorption, uniaxial compressive strength and compressive wave velocity. The geomechanical properties were compared with the weathering classifications of ISRM (Rock characterization, testing and monitoring, p 211, 1981) and Kilic (Environ Eng Geosci 4:475–483, 1999)

Abstracts of The Paper Published only In The Turkish Edition of This Bulletin The Geology and Petrography of The Late Neoproterozoic-Early Paleozoic Units of Western Taurides (SW Of Sandıklı, Afyon)

S OF THE PAPER PUBLISHED ONLY IN THE TURKISH EDITION OF THIS BULLETIN THE GEOLOGY AND PETROGRAPHY OF THE LATE NEOPROTEROZOIC EARLY PALEOZOIC UNITS OF WESTERN TAURIDES (SW OF SANDIKLI, AFYON) Semih GURSU* and M. Cemal GONCUOĞLU** Abstract.The investigated area including the region of the junction of the Middle and Western Taurides, comprise distinctive Middle Taurides stratigraphy and tectonic features. The units, cropped out in Sandikli, Karadirek, Basagac, Akharim, Tasoluk and surrounding areas are divided into three parts as Sandikli Basement Complex, Early Paleozoic Cover Units and Mesozoic Cover Units. Sandikli Basement Complex is composed of Guvercinoluk formation and Kestel Cayi Porphyroid Suite from bottom to top; Early Paleozoic cover units consist of Gogebakan, Hudai, Caltepe and Seydisehir formations respectively; Ilyasli and Derealani formations represent Mesozoic cover units. Mesozoic Cover Units is technically overlain by Sandikli Basement Complex in the western part of the Sandikli. Sandikli Basement Complex is formed an overturned antiformal structure within NNW SSW direction. Meta-sedimentary and meta-magmatic rocks of Sandikli Basement Complex are described as Guvercinoluk formation and Kestel Cayi Porfiroid Suite. Kestel Cayi Porphyroid Suite is composed of meta-rhyolite/meta-dacite and meta-quartz porphyry dikes. Meta-quartz porphyry dikes of Kestel Cayi Porphyroid Suite intrude the meta-sedimentary rocks of SBC (Guvercinoluk formation) and meta-rhyolite/meta-dacite rocks which formed rhyolitic composition carapace. Sandikli Basement Complex are cut by green-dark green colored continental tholeiitic basalt compositions dikes. Sandikli Basement Complex rocks are unconformably overlain by Early Cambrian Gogebakan formation. Upward, the formation is transitional to Celiloglu member of Hudai forma tion. The unit's age indicate Tommotian (Early Cambrian) age according to trace fossils at the transition between Celiloglu member of Hudai formation and Gogebakan formation. Celiloglu member is made up of alternation of green colored meta-mudstone/meta-siltstone and green-beige colored meta-sandstone and is transitional to Orenkaya quartzite member with slate bearing meta-sandstone (quartzite). Hudai formation is conformably overlain by Lower-Middle Cambrian Caltepe formation, which is made up of reddish-brown colored recrystalized dolomite and pink colored nodular limestones. The unit continues Middle Cambrian Early Ordovician Seydisehir formation including anchi-metamorphic milstone, nodular limestones, shales and sandstones, which have a narrow contact in the investigated area. Mesozoic cover units are represented by Early Liassic Ilyasli formation with Early Liassic-Early Malm Derealani formation. It is considered that the unconformity of Sandikli Basement Complex and Early Cambrian cover units correspond to Main Pan-African unconformity in Menderes Massif (Sengor et. al., 1984) and Menderes Massif, Eastern Taurides and similar units are pertaining to parts of PanAfrican basement.The investigated area including the region of the junction of the Middle and Western Taurides, comprise distinctive Middle Taurides stratigraphy and tectonic features. The units, cropped out in Sandikli, Karadirek, Basagac, Akharim, Tasoluk and surrounding areas are divided into three parts as Sandikli Basement Complex, Early Paleozoic Cover Units and Mesozoic Cover Units. Sandikli Basement Complex is composed of Guvercinoluk formation and Kestel Cayi Porphyroid Suite from bottom to top; Early Paleozoic cover units consist of Gogebakan, Hudai, Caltepe and Seydisehir formations respectively; Ilyasli and Derealani formations represent Mesozoic cover units. Mesozoic Cover Units is technically overlain by Sandikli Basement Complex in the western part of the Sandikli. Sandikli Basement Complex is formed an overturned antiformal structure within NNW SSW direction. Meta-sedimentary and meta-magmatic rocks of Sandikli Basement Complex are described as Guvercinoluk formation and Kestel Cayi Porfiroid Suite. Kestel Cayi Porphyroid Suite is composed of meta-rhyolite/meta-dacite and meta-quartz porphyry dikes. Meta-quartz porphyry dikes of Kestel Cayi Porphyroid Suite intrude the meta-sedimentary rocks of SBC (Guvercinoluk formation) and meta-rhyolite/meta-dacite rocks which formed rhyolitic composition carapace. Sandikli Basement Complex are cut by green-dark green colored continental tholeiitic basalt compositions dikes. Sandikli Basement Complex rocks are unconformably overlain by Early Cambrian Gogebakan formation. Upward, the formation is transitional to Celiloglu member of Hudai forma tion. The unit's age indicate Tommotian (Early Cambrian) age according to trace fossils at the transition between Celiloglu member of Hudai formation and Gogebakan formation. Celiloglu member is made up of alternation of green colored meta-mudstone/meta-siltstone and green-beige colored meta-sandstone and is transitional to Orenkaya quartzite member with slate bearing meta-sandstone (quartzite). Hudai formation is conformably overlain by Lower-Middle Cambrian Caltepe formation, which is made up of reddish-brown colored recrystalized dolomite and pink colored nodular limestones. The unit continues Middle Cambrian Early Ordovician Seydisehir formation including anchi-metamorphic milstone, nodular limestones, shales and sandstones, which have a narrow contact in the investigated area. Mesozoic cover units are represented by Early Liassic Ilyasli formation with Early Liassic-Early Malm Derealani formation. It is considered that the unconformity of Sandikli Basement Complex and Early Cambrian cover units correspond to Main Pan-African unconformity in Menderes Massif (Sengor et. al., 1984) and Menderes Massif, Eastern Taurides and similar units are pertaining to parts of PanAfrican basement.

Diagenetic to low-grade metamorphic evolution of clay mineral assemblages in Palaeozoic to early Mesozoic rocks of the Eastern Taurides, Turkey

AbstractPalaeozoic to early Mesozoic rocks of both autochthonous and allochthonous units of the Eastern Tauride Belt have different textural and mineralogical features related to their varying deposition regimes and thermal histories. The Devonian and Carboniferous formations in the allocthonous units have anchizonal to epizonal grades of metamorphism, whereas those of the autochthon experienced only early diagenetic conditions. A well-developed penetrative slaty cleavage is also found in Devonian formations of the allocthonous units, which is not observed in equivalent rocks of the autochthon. Phyllosilicates of the uncleaved diagenetic assemblages consist mainly of illite, chlorite, kaolinite, mixed-layer illite-smectite, chlorite-vermiculite and chloritesmectite, whereas in addition to these, metamorphic allochthonous units contain some index minerals such as dickite, paragonite, Na and K mica, pyrophyllite, stilpnomelane and chloritoid. These latter assemblages show a higher degree of textural and mineralogical maturation and lower b cell dimensions than the autochthonous rocks, suggesting that they originated in a relatively high heat flow basin such as an extensional setting.

Frasnian Brachiopoda Fauna From The Late Devonian Gümüşali Formation In The Saimbeyli Region (Adana-Eastern Taurides)

In this study, Frasnian brachiopoda fauna of the Gumuþali formation in the Saimbeyli area (Eastern Taurides) has been identified and described for the first time in Turkey. The measured section, located near Naltaþ village, Gumuþali formation is well exposed and very rich in macrofossils. This macrofossils occur in local accumulations within the limestones and sandstones. The section which represents lower part of the formation is formed by fossiliferous limestones at the basal part, by sandy limestone-shale alternation at the middle part and by sandstones interbedded with thin shales at the top. The sequence was deposited in a shallow marine environment. It contains brachiopods, corals and subordinate bryozoa and crinoidal elements. The detemined brachiopoda assemblage includes Douvillina dutertrei (Murchison), Cyphoterorhynchus arpaensis (Abramian), Desquamatia sp., Cyrtospirifer bisinus (Lehon), Cyrtospirifer schelonicus Nalivkin, Cyrtospirifer sp., Apousiella bouchardi (Murchison), Spinatrypina chitralensis (Reed), Uchtospirifer multiplicatus Brice. This assemblage can be correlated with those from the Frasnian of Iran, Afghanistan and Western Europe.

Volcanism, sedimentation and massive sulfide mineralization in a Late Cretaceous arc-related basin, Eastern Taurides, Turkey

Late Cretaceous arc volcanism and associated massive sulfide mineralizations occur in the Eastern Taurus Mountains. The mineralizations are related to felsic (dacitic–rhyolitic) volcanic rocks which, together with basement rocks, form the lowermost levels of a 5000 m thick volcano-sedimentary sequence, and are restricted to a few levels within the sequence. Basaltic rocks, which are intruded by tonalite and dacite, form the base of the volcano-sedimentary sequence. The dacitic–rhyolitic rocks are overlain by a volcano-sedimentary succession with andesitic–dacitic flows. The flows do not contain any mineralization. This succession starts with volcanic breccia and tuffs at the base, passing into crystal-rich sandstone, and pelagic mudstone with tuffite intercalations, and ends with marls intercalated with sandstones basalt and peridotite olistoliths. The felsic rocks bear stockwork and disseminated types of mineralization. The massive sulfide mineralization has a simple mineral assemblage of pyrite, chalcopyrite, bornite and sphalerite. Optical microscopic examination of pyrites from Derince Massive Sulfide Deposits reveals that the pyrites are commonly seen in framboidal and cubic forms. The geochemistry of the magmatic rocks and sedimentary facies associations indicate that the mineralizations in the Derince were developed in an intra-arc environment.

The Late Cretaceous palaeolatitude of the Neotethyan spreading axis in the eastern Mediterranean region

A compilation of available palaeomagnetic data from the Troodos (Cyprus) and Baër–Bassit (Syria) ophiolitic terranes of the eastern Mediterranean Tethyan orogenic belt is presented. The ophiolites represent fragments of oceanic lithosphere generated at a Neotethyan spreading axis in the Late Cretaceous, although debate continues over the tectonic setting of this spreading axis and its position within the eastern Mediterranean palaeogeography. Two types of model reconstructions have been proposed: Type 1—the ophiolites formed in a southerly Neotethyan basin by spreading above an oceanic subduction zone. The Baër–Bassit ophiolite was then emplaced a relatively short distance (tens of kilometers) southwards on to the Arabian continental margin, leaving the Troodos ophiolite isolated in an intra-oceanic setting to the west; and Type 2—the ophiolites formed in a northerly Neotethyan basin by spreading at a ‘normal’ oceanic ridge, with subsequent large-scale thrusting (hundreds of kilometers) to the south of emplaced ophiolites over microcontinental fragments to reach their present positions. Palaeomagnetic determination of the palaeolatitude of the Neotethyan spreading axis is, therefore, of considerable interest.Previous palaeomagnetic analyses have demonstrated the presence of significant, and in some cases extreme, relative tectonic rotations of a variety of origins in both ophiolites. To allow palaeomagnetic data from these rotated units to be combined, an inclination-only formulation of the palaeomagnetic tilt test is employed. This provides unequivocal evidence that both ophiolites retain pre-deformational remanent magnetizations, which are interpreted as original ocean-floor magnetizations acquired close to the time of crustal formation in the Late Cretaceous. The mean inclinations of 37.0±2.6° for the Troodos terrane and 41.1±3.4° for the Baër–Bassit terrane indicate respective palaeolatitudes for the spreading axes of 20.6°N±1.8° and 23.6°N±2.5°, consistent with a Late Cretaceous position between the Arabian and Eurasian margins. These data, together with a well-defined palaeolatitude of 25.5°N±4.5° for the eastern Pontides previously reported in the literature, provide constraints which must be incorporated in any successful tectonic reconstruction of the eastern Mediterranean Tethys. The implications of these constraints for Type 1 and 2 models are discussed using a series of plate tectonic cross-sections constructed along a line extending northwards from the Arabian continental margin. In the absence of palaeomagnetic data from Late Cretaceous rocks of the eastern Taurides, however, it is presently impossible to use these palaeolatitudinal constraints to resolve the root zone debate on a purely palaeomagnetic basis. Solutions which satisfy the constraints may be found for both types of model reconstruction. Additional, published field-based geological considerations, however, strongly support models in which the Troodos and Baër–Bassit (and other southerly) ophiolites were generated in a southern Neotethyan basin, rather than those involving generation in a northerly basin and subsequent large-scale thrust displacement to the south.

Stratigraphical evidence for the depression of the northern margin of the Menderes–Tauride Block (Turkey) during the Late Cretaceous

Upper Cretaceous units on the Menderes–Tauride Block show a transition from a passive continental margin to a pelagic basin. This transition is related to the emplacement of ophiolitic nappes. The pelagic sediments were studied in the Aydıncık and Arslanköy (Mersin) areas in the central Tauride region, and in the Munzur Mountains in eastern Tauride region. In the Aydıncık area Upper Cretaceous units consist of Upper Campanian carbonate breccias with rudist fragments; Upper Campanian–Lower Maastrichtian slope-to-basinal sediments overlie these carbonate breccias disconformably. In the Arslanköy area the Upper Campanian–Maastrichtian Yavca Formation consists of Globotruncana-bearing biomicrites, siliciclastic turbidites, calciturbidites and debris flows and overlies Jurassic–Cretaceous platform carbonates disconformably. The uppermost levels of the Liassic–Cenomanian platform carbonates in the Munzur Mountains are composed of Cenomanian Hippurites/Orbitolina-bearing reefal limestones and then Turonian–Campanian Globotruncanidae-bearing biomicrites.The stratigraphic sequence in the Menderes–Tauride Block shows that rifting to form a northern Neotethyan basin took place in the Triassic and gave rise to the Inner Tauride Ocean. From Jurassic to Cenomanian times, the northern part of the Menderes–Tauride Platform formed a passive continental margin. In the Late Cretaceous the Inner Tauride Ocean is believed to have commenced intra-oceanic, northward subduction. Inner Tauride oceanic crust-derived nappes were emplaced southward onto the Menderes–Tauride Block. Flexural foreland basins in which pelagic sediments were deposited were formed in the Taurus Mountains related to southward thrusting and the emplacement of the ophiolite nappes.

Paleomagnetic reconstruction of the Cenozoic evolution of the Eastern Mediterranean

A total of 113 paleomagnetic sites were sampled along an Anatolian S–N transect from the Arabian platform, the Hatay region, the Eastern Taurides, the Kirsehir block, the Sivas basin and the Eastern Pontides. Reliable characteristic remanent paleomagnetic directions were retrieved from 37 of these sites, spanning in time from Paleocene to Miocene. In a general way, declinations are westerly deviated and inclinations are shallower than the geocentered dipole value at the present latitudes. When combined with previously published results, these data indicate that a large-scale counterclockwise rotation of Anatolia of some 25° has occurred since the Miocene. Assuming that the pole of rotation of Anatolia with respect to Europe has remained constant in time at the location given by MacClusky et al. [J. Geophys. Res. 105 (2000) 5695] on the basis of the geodetic data, this rotation implies that a large westward displacement (500 km at the average latitude of 40°) has taken place. Assuming that the rotation was initiated by the Arabia/Europe collision about 12 Ma ago, this corresponds to an average displacement of about 40 mm/year. Together with previous results from the western part of the Aegean arc, these results indicate that the main trends of the Cenozoic evolution of the Eastern Mediterranean appear to consist of two post-early Miocene rotations of opposite senses: a clockwise rotation of the western part of the Aegean [Tectonophysics 146 (1988) 183] around a pole situated in northern Albania, and a counterclockwise rotation around the pole given by McClusky et al. [J. Geophys. Res. 105 (2000) 5695]. Comparison with GPS data suggest that both rotations are still active today.

The supra-subduction zone Pozanti–Karsanti ophiolite, southern Turkey: evidence for high-pressure crystal fractionation of ultramafic cumulates

The Pozanti–Karsanti ophiolite (PKO), forming one of the late Cretaceous discontinuous oceanic lithosphere remnants in the eastern Tauride belt in southern Turkey, is characterized by mantle tectonites, ultramafic and mafic cumulates, isotropic gabbros, sheeted dikes and volcanics. Well-preserved crustal cumulate rocks are mainly composed of dunite±chromite, wehrlite, olivine clinopyroxenite, clinopyroxenite, olivine websterite and low-Ti gabbro. The crystallization order in the plutonic section is olivine (Fo 93–83)±chromian spinel [(Cr/Cr+Al)=79], clinopyroxene [(Mg/Mg+Fe)=93–87], orthopyroxene [(Mg/Mg+Fe)=90–83]. The mineral chemistry of the ultramafic cumulates forming the basal portion of the plutonic section of the Pozanti–Karsanti ophiolite (PKO) is not consistent with crystal–liquid fractionation of primitive mid-ocean ridge basalts at low pressures. The presence of highly magnesian clinopyroxene and orthopyroxene together with the absence of plagioclase, as early fractionating phases, indicate medium- to high-pressure (up to 10 kbar) crystal fractionation of primary basaltic melts. Mineralogical and geochemical data suggest that the ultramafic cumulates are distinct from rocks in mid-ocean ridge and back-arc basin ophiolites. The ultramafic rocks instead represent part of the plutonic core of an intraoceanic island arc/suprasubduction zone tectonic setting. It is believed that the arc crust was thick for the PKO during the late Cretaceous, with the existence of an active magma chamber situated at the base of the crust around pressure of 8–10 kbar for the high-pressure products and a related active shallower level magma chamber for the low-pressure products.