Southern Neotethys Research Articles

Upper Miocene–Pleistocene deformation of the Girne (Kyrenia) Range and Dar Dere (Ovgos) lineaments, northern Cyprus: role in collision and tectonic escape in the easternmost Mediterranean region

Abstract During Late Cretaceous–Mid-Eocene the Girne (Kyrenia) Range formed part of the northerly active continental margin of the southern Neotethys. Following Late Eocene–Late Miocene mainly deep-marine clastic deposition, the range was thrust southwards in a convergent (transpressional) stress regime during Late Miocene (Messinian)–earliest Pliocene time. Sinistral transpression is most evident near the front of the range in the east and in several segments, implying strain compartmentalization. The range was relatively quiescent during Early–Mid Pliocene, followed by strong c. east–west-trending uplift during Late Pliocene–Pleistocene. Further south, the east–west Dar Dere (Ovgos) lineament was active as a north-down extensional (or transtensional) fault zone during Oligocene–Mid-Miocene. Sinistral strike-slip/transpression followed during Late Miocene, followed by strike-slip at least during Late Pliocene–Pleistocene. The latest Miocene–earliest Pliocene thrusting/oblique convergence reflects closure of the southern Neotethys and tightening of the suture between the Arabian (North African) and Turkish (Eurasian) continents. Collision-related uplift of the Girne (Kyrenia) Range and the Troodos Massif further south took place from Late Pliocene time onwards. The Dar Dere (Ovgos) lineament is interpreted as a terrane boundary that was reactivated related to westward tectonic escape of Anatolia during Neogene–Recent time. The structure as a whole reflects regional diachronous continental collision. Supplementary material: Detailed geological maps of key areas to the south and north of the Girne (Kyrenia) Range based on regional mapping and field observations are available at www.geolsoc.org.uk/SUP18534 .

Ultrapotassic Mafic Rocks as Geochemical Proxies for Post-collisional Dynamics of Orogenic Lithospheric Mantle: the Case of Southwestern Anatolia, Turkey

High-Mg ultrapotassic volcanic rock occurrences of lamproitic affinity are exposed in southwestern Anatolia, mostly within the Menderes Massif. From north to south the lamproitic volcanism shows increasingly younger ages ranging from 20 to 4 Ma. Volcanism is contemporaneous with more voluminous shoshonitic, high-K calc-alkaline, and ultrapotassic magmatic activity in the Simav–Selendi, Usak, Kirka, Koroglu, Afyon and Isparta–Golcuk areas. The southward decrease in the age of the volcanism correlates with changes in geochemical composition, particularly a decrease in 87Sr/86Sr, 207Pb/204Pb, Zr/Nb and Th/Nb, and an increase in 143Nd/144Nd, 176Hf/177Hf, 206Pb/204Pb, 208Pb/204Pb and Ce/Pb, thus delineating a systematic change from orogenic (crust-like) to anorogenic (convecting mantle-like) signatures. Rare earth element compositions of clinopyroxene phenocrysts demonstrate an increasing role for residual garnet for locations in the central parts of the Menderes Massif, indicating a lithosphere thickness greater than 80 km. In contrast, K2O abundances remain nearly constant at around 7%, indicating buffering by phlogopite in the mantle source. Magma genesis in southwestern Anatolia is controlled by post-collisional extensional events initiated after major lithospheric thickening. Geochemical constraints suggest that the mantle source experienced two main geodynamic stages. The first stage caused ultradepletion of the mantle and subsequent metasomatic enrichment, which allowed coupling of the geochemical signatures of ultradepleted harzburgite with those of crust-derived sediments. This happened during the final closure stages of the southern Neotethys Ocean and the accretion of forearc oceanic lithosphere (island-arc type), as shallowly subducted material to the Anatolian lithosphere. The second stage is post-collisional, and is related to the collapse of the orogenic belt and the development of extension-related horst and graben structures. This stage is concurrent with the initiation of a thermal anomaly originating from a gap, identified by seismic tomography, in the subducted slab under western Anatolia. We propose that the lithospheric mantle underwent intense ‘asthenospherization’ owing to lithosphere–asthenosphere interaction, caused by the southward expansion of this gap during slab roll-back. The geochemical resemblance of the lamproites to more voluminous, contemporaneous shoshonitic magmas implies their derivation from a heterogeneous mantle source that had been affected by similar processes. These mantle processes may be closely associated with the major episode of uplift in the Menderes Massif.

Late Eocene–Neogene sedimentary geology of the Girne (Kyrenia) Range, northern Cyprus: A case history of sedimentation related to progressive and diachronous continental collision

Sedimentary geology can shed light on the processes of continental collision. The easternmost Mediterranean provides an exceptional opportunity to study sediments deposited during progressive and diachronous continental collision, with implications for comparable settings elsewhere. Here, we focus on sediment sources, pathways and deposition of mostly deep-sea clastic sediments exposed in northern Cyprus. The sedimentary basin forms part of the northern continental margin of the Southern Neotethys ocean and is represented by a ca. 200km-long, E–W-trending, arcuate lineament, encompassing northern Cyprus and its submarine link with Turkey. The Upper Eocene–Upper Miocene basin was divided into northerly and southerly sub-basins during Mid- to Late Miocene time by an E–W-trending, inferred syn-depositional fault lineament. The sequence begins with non-marine to shallow-marine basal conglomerates (Late Eocene) that abruptly fine upwards into siliciclastic turbidites (Oligocene), followed by biogenic calciturbidites and marls (Aquitanian–Langhian). During Mid–Late Miocene the northerly sub-basin was characterised by thin- to medium-bedded calciturbidites and marls (Serravallian), overlain by thick-bedded, medium-grained lithic sandstones (Tortonian). In contrast, the southern sub-basin is dominated by siliciclastic turbidites with abundant sole structures (Burdigalian–Tortonian). Palaeocurrent evidence indicates dominantly westward sediment transport, especially during the Late Miocene. The Serravallian–Tortonian sandstones of the northern sub-basin are relatively rich in carbonates, while the southern sub-basin contains more siliciclastic and ophiolite-derived detritus indicating differences in sediment supply. In general, the Upper Eocene basal conglomerates were mainly derived from the north, from within the Girne (Kyrenia) Range and its inferred northward extension. In response to rapid subsidence (reflecting possible southward subduction zone retreat) clastic sediment sources to the north then submerged while clastic sediment was instead mainly supplied from the South Neotethyan suture zone to the east and northeast in southern Turkey. Reflecting diachronous collision, deep-water deposition persisted in the easternmost Mediterranean basin further west until this was terminated in northern Cyprus by thrusting/folding during latest Miocene–earliest Pliocene. Quaternary collision-related uplift ensued. Similar sedimentary development is to be expected in collisional settings elsewhere (e.g. Tethyan closure in the Himalayas; Iapetus closure in the Appalachians).

Evidence from the Kyrenia Range, Cyprus, of the northerly active margin of the Southern Neotethys during Late Cretaceous–Early Cenozoic time

AbstractSedimentary geology and planktonic foraminiferal biostratigraphy have shed light on the geological development of the northern, active continental margin of the Southern Neotethys in the Kyrenia Range. Following regional Triassic rifting, a carbonate platform developed during Jurassic–Cretaceous time, followed by its regional burial, deformation and greenschist-facies metamorphism. The platform was exhumed by Late Maastrichtian time and unconformably overlain by locally derived carbonate breccias, passing upwards into Upper Maastrichtian pelagic carbonates. In places, the pelagic carbonates are interbedded with sandstone turbidites derived from mixed continental, basic volcanic, neritic carbonate and pelagic lithologies. In addition, two contrasting volcanogenic sequences are exposed in the western-central Kyrenia Range, separated by a low-angle tectonic contact. The first is a thickening-upward sequence of Campanian–Lower Maastrichtian(?) pelagic carbonates, silicic tuffs, silicic lava debris flows and thick-bedded to massive rhyolitic lava flows. The second sequence comprises two intervals of basaltic extrusive rocks interbedded with pelagic carbonates. The basaltic rocks unconformably overlie the metamorphosed carbonate platform whereas no base to the silicic volcanic rocks is exposed. Additional basaltic lavas are exposed throughout the Kyrenia Range where they are dated as Late Maastrichtian and Late Paleocene–Middle Eocene in age. In our proposed tectonic model, related to northward subduction of the Southern Neotethys, the Kyrenia platform was thrust beneath a larger Tauride microcontinental unit to the north and then was rapidly exhumed prior to Late Maastrichtian time. Pelagic carbonates and sandstone turbidites of mixed, largely continental provenance then accumulated along a deeply submerged continental borderland during Late Maastrichtian time. The silicic and basaltic volcanogenic rocks erupted in adjacent areas and were later tectonically juxtaposed. The Campanian–Early Maastrichtian(?) silicic volcanism reflects continental margin-type arc magmatism. In contrast, the Upper Maastrichtian and Paleocene–Middle Eocene basaltic volcanic rocks erupted in an extensional (or transtensional) setting likely to relate to the anticlockwise rotation of the Troodos microplate.

Pervasive Palaeogene remagnetization of the central Taurides fold-and-thrust belt (southern Turkey) and implications for rotations in the Isparta Angle

The Turkish Anatolide-Tauride block rifted away from the northern margin of Gondwana in the Triassic, which gave way to the opening of the southern Neo-Tethys. By the late Palaeocene to Eocene, it collided with the southern Eurasian margin, leading to the closure of the northern Neo-Tethys ocean. To determine the position of the Anatolide-Tauride block with respect to the African and Eurasian margin we carried out a palaeomagnetic study in the central Taurides belt, which constitutes the eastern limb of the Isparta Angle. The sampled sections comprise Carboniferous to Palaeocene rocks (mainly limestones). Our data suggest that all sampled rocks are remagnetized during the late Palaeocene to Eocene phase of folding and thrusting event, related to the collision of the Anatolide-Tauride block with Eurasia. To further test the possibility of remagnetization, we use a novel end-member modelling approach on 174 acquired isothermal remanent magnetization (IRM) curves. We argue that the preferred three end-member model confirms the proposed remagnetization of the rocks. Comparing our data to the post-Eocene declination pattern in the central Tauride belt, we conclude that our clockwise rotations are in agreement with data from other studies. After combining our results with previously published data from the Isparta Angle (that includes our study area), we have reasons to cast doubt on the spatial and temporal extent of an earlier reported early to middle Miocene remagnetization event. We argue that the earlier reported remagnetized directions from Triassic rocks--in tilt corrected coordinates--from the southwestern Antalya Nappes (western Taurides), are in good agreement with other studies from the area that show a primary origin of their characteristic remanent magnetization. This implies that we document a clockwise rotation for the southwestern Antalya Nappes since the Triassic that is remarkably similar to the post-Eocene (∼40°) rotation of the central Taurides. For the previously published results that are clearly remagnetized, we argue that their remagnetization has occurred in the Palaeocene to Eocene.

Geophysical and geological imprints of southern Neotethyan subduction between Cyprus and the Isparta Angle, SW Turkey

The present-day eastern Mediterranean region is characterized by two main arc systems: the western Hellenic arc and the eastern Cyprian arc, the latter having no significant trench unlike the former. Therefore, plate interactions in the western-northwestern side of the island of Cyprus is a matter of debate concentrating mainly on subduction or wrench systems. In order to understand the plate interactions within the area between the Isparta Angle and western segment of the Cyprus arc, the epicenter distribution of earthquakes, b-values and gravity anomalies for 5 depth intervals (0–35 km, 35–55 km, 55–75 km, 75–95 km, >95 km) have been analyzed on NE-SW trending regional profiles, and compared with geological structures. Although there are no earthquakes with depths greater than 50 km (i.e. crustal scale earthquakes) in the northern part of the Isparta Angle, all earthquake epicenters lie on a linear zone from southwest of Cyprus to the northwest, nearly parallel to the NW-SE trending Florence Rise. The b-value distribution shows a very good consistency with the epicentral and tectonic maps of Antalya Bay. The b-value maps, deeper than 55 km, show that low b-values depicting a NW-SE trending linear pattern correspond to seismic zones. Furthermore, this pattern shifts to the northeast and resembles the epicenters of the deep-focus earthquakes on the northeast dipping plane supporting the existence of a subduction zone. The gravity profiles show low gravity anomalies along the Florence Rise, high gravity anomalies at a certain distance interval to the NE direction which presumably resulted from subducting oceanic lithosphere, and again low gravity anomalies corresponding to the end of subducting slab and continental eastern limb of the Isparta Angle. On the other hand, the observed gravity anomalies are found to be consistent with the earthquake distribution patterns in the area. As a conclusion, for the area between the apex of the Isparta Angle and the western Cyprian arc, the distribution of earthquake epicenter locations, b-values, and gravity data suggest the presence of a subduction zone inclined to the northeast beneath the eastern limb of the Isparta Angle.

Lamproites as indicators of accretion and/or shallow subduction in the assembly of south-western Anatolia, Turkey

The geochemistry and mineralogy of lamproites from south-western Anatolia can be used as a snapshot of the lithospheric composition beneath the Menderes Massif. High and near-constant K2O contents, the presence of mantle xenocrystic phlogopite and olivine, highly magnesian olivine phenocrysts and Cr-rich spinel inclusions all indicate that the lithospheric mantle was phlogopite-bearing ultradepleted harzburgite at the time of lamproite eruption (20–4 Ma). This mantle assemblage most probably originated in a complex multistage process, including (intra-oceanic) supra-subduction zone depletion during the final stages of southern Neotethyan ocean closure, and accretion of the forearc oceanic lithosphere as shallowly subducted material to the already assembled Anatolia. The data presented here support shallow subduction of the oceanic lithosphere as a cause of the uplift of the Menderes Massif, in contrast to the traditional core-complex model. Terra Nova, 00, 000–000, 2010

Sequence stratigraphy and carbon isotope stratigraphy of an Aptian mixed carbonate-siliciclastic platform to basin transition (Galve sub-basin, NE Spain)

Abstract A 380 m thick Aptian platform to basin transition has been studied along a 16 km long transect of excellent and continuous outcrops in NE Spain. The series has been dated using biostratigraphy (foraminifera and ammonites) and carbon-isotope stratigraphy, and has been subdivided at four scales of depositional sequences. The Aptian marine succession is subdivided into two-large scale sequences separated by a middle Aptian sub-aerial exposure surface. A characteristic trend of the floral-faunal fossil assemblages is present, which evolves from orbitolinid-ooid dominated ramps in Sequence I-1, to a coral-stromatoporoid-microbialite dominated platform in Sequence I-2, to a rudist-dominated platform top in Sequence II-1, and finally to a second episode of orbitolinid-ooid dominated ramp system in Sequence II-2. There was an influx of siliciclastic sediments at the base and at the top of this succession. The detailed carbon-isotope curve measured along the Miravete section and covering almost the complete Aptian succession, is compared with published Aptian curves recorded in both basinal and carbonate platform settings along the northern and southern NeoTethys margins. It shows that the Galve sub-basin curve represents all the major isotope excursions of the lower and upper Aptian, in a dominantly shallow-water succession.

Landscape development within a young collision zone: implications for post-Tethyan evolution of the Upper Tigris River system in southeastern Turkey

The geomorphic evolution of the upper basin of the Tigris (Dicle) River in southeastern Turkey reflects the interplay of surface processes and the development of topographic relief and lithospheric deformation since the closing of the Southern Neo-Tethyan (formerly Bitlis) Ocean. The study of the Tigris system is a proxy for understanding the deep crustal processes associated with the active Alpine–Himalayan mountain belt. The drainage morphology is linked to the uplift of the eastern Taurus Mountains and deformation of the Arabian foreland system following continent–continent collision. Initial review of landscape features at aerial and field scales confirms that the evolution of the Tigris has been complex, and that valley morphology varies by reach. Within the headwater reach, the Tigris is a transverse river system that flows across metamorphic rocks of the Bitlis–Zagros Suture Zone. Ongoing deformation in the Lake Hazar region bounded by the East Anatolian Fault Zone controls the topographic divide between the watershed draining north to the Euphrates and south to the Tigris. At the junction of the Arabian Plate, the river may be viewed as an antecedent stream system that developed since the Miocene. In the reach near Diyarbakir, valley development (and possibly incision) has been influenced by recent effusive volcanism. East of Diyarbakir, evaporitic karst processes are currently causing sapping, piping, and subsurface collapse as well as valley widening, which is concentrated in folds paralleling the suture zone and orogen to the north. The evolution of the Upper Tigris over the past 13 Myr can be reconstructed as a function of vertical movement (e.g. base-level changes, tectonic uplift, doming, downwarp, and sagging), horizontal deformation (e.g. folding, faulting, compression, and extension), volcanism, weathering, and erosion (e.g. dissolution processes, karstic erosion, and sapping). It is important to assess the first-order tectonic controls on the evolving fluvial systematics of the Tigris so that its sedimentary and geomorphic records can be used to reconstruct hydroclimatic changes affecting this part of the Near East during antiquity.

Record of Cenozoic sedimentation from the Amanos Mountains, Southern Turkey: Implications for the inception and evolution of the Arabia–Eurasia continental collision

The sedimentary succession of the southern Amanos Mountains, bordering the eastern margin of the Karasu Rift in south central Turkey, provides a record of environmental change from the Eocene (Lutetian) to the Upper Miocene (Tortonian) that charts the final evolution of the northern margin of the Arabian plate prior to and during continental collision. Eocene shallow-marine carbonates (Hacıdağı Formation) are interpreted as the youngest unit of the Arabian passive margin succession deposited on a northwards facing carbonate ramp. Subsequent deformation and uplift took place during the Oligocene represented by folding of the Eocene and older strata. This is interpreted to be the result of initial continental collision between Arabia and Eurasia. Unconformably overlying the Eocene limestone are Lower Miocene conglomerates, sandstones and palaeosols up to 150 m thick (Kıcı Formation). These were deposited in a range of marginal marine settings consisting of alluvial fan/fan delta facies, flood plain as well as basinal facies. Subsequently, during the Middle Miocene, local patch reefs developed in restricted areas (Kepez Formation) followed by Upper Miocene sediments (Gökdere Formation) composed of relatively deep water hemipelagic marl, with clastic interbeds, which represent a transgression during this period. The Upper Miocene becomes sandier upwards, this records the regression from the relatively deep water facies to coastal sediments. Water depth gradually became shallower until during Pliocene time the area became continental in nature. By the Quaternary rifting had resulted in the development of the Karasu Rift with active alluvial fans along the margins and braided rivers depositing coarse conglomerates in the axial zone. These conglomerates are interbedded with basaltic lava flows that resulted from the region extension across the area. This research shows that initial continental collision occurred in this area after the Lutetian (40.4 Ma) and before the Aquitanian (23.03 Ma) supporting the hypothesis that the southern Neotethys Ocean closed during the Late Eocene to Oligocene. This was a time of climatic change including the onset of southern hemisphere glaciation, in which the closure of the southern Neotethys may have had played an important role.

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.

Tectonic significance of the geochemistry and petrology of ophiolites in southeast Anatolia, Turkey

The southeast Anatolian ophiolites form discontinuous linear belts of oceanic fragments immediately north of the Bitlis–Zagros suture, which marks a continental collision zone between the Arabian platform to the south and the Taurides to the north. The Late Cretaceous ophiolites in the southeast Anatolia are represented by the Kızıldağ in the Hatay area, the Göksun and the Berit to the north of Kahramanmaraş, İspendere in the Malatya area and Kömürhan–Guleman in the Elazığ area. The Göksun, Berit, İspendere, Kömürhan and Guleman ophiolites were attached to the base of the Tauride platform (i.e. the Malatya–Keban) along its northern active margin and intruded by the I-type calc-alkaline granitoids of Late Cretaceous age. In contrast, the Kızıldağ (Hatay) ophiolite was thrust over the Arabian passive margin in the south. The cumulate rocks in the ophiolites are represented by dunite, wehrlite, lherzolite, olivine clinopyroxenite, olivine gabbronorite, olivine gabbro, gabbronorite and gabbro. Highly magnesian olivines (Fo 88 to 74) and pyroxenes (Mg# 95 to 60) as well as highly calcic plagioclases (An 95 to 68) from the cumulate rocks differ from oceanic equivalents, which mainly formed from a MOR basaltic melt. The order of crystallization in mineral phases, whole rock and mineral chemistry data from the cumulates suggest that the primary magma is compositionaly similar to that observed in modern island arc tholeiitic sequences. The volcanic and subvolcanic rocks exhibit tholeiitic compositions. Chondrite normalized REE, N-MORB normalized multi-element patterns and tectonic discrimination diagrams suggest the existence of two main types of parental basic magmas in the crustal rocks of the SE Anatolian ophiolites. These are (i) IAT series that characterize the Kızıldağ, Göksun, İspendere, Kömürhan and Guleman ophiolites and (ii) Low-Ti boninitic series known only in the Kızıldağ ophiolite. The geochemistry of the crustal rocks suggests that they formed in a suprasubduction zone tectonic setting, including arc–forearc environments in the southern Neotethys. These well-preserved plutonic oceanic crustal remnants mainly exhibit an intact ophiolite pseudostratigraphy and are overlain by a volcanic-sedimentary unit made up of alternations of basic to acidic extrusive rocks, debris flows, volcaniclastic sandstones and pelagic limestones, interpreted as a tholeiitic ensimatic island arc assemblage built on the suprasubduction zone type crust. The metamorphism of some of the ophiolites (i.e. Berit) in the SE Anatolia might be related to later stages of intraoceanic subduction during the evolution of the southern Neotethys.

The Miocene of the Hatay area, S Turkey: Transition from the Arabian passive margin to an underfilled foreland basin related to closure of the Southern Neotethys Ocean

Miocene sediments of the Hatay area document the distal, southerly, part of an “underfilled” peripheral foreland basin related to the closure of the Southern Neotethys. The basin is underlain by latest Cretaceous and Eocene shallow-marine carbonates, interpreted as the youngest part of the Arabian passive margin succession. Unconformably overlying Lower Miocene conglomerates, sandstones and palaeosols (up to 250 m thick) represent braided river deposits derived from an uplifted area to the south. During the Middle Miocene, carbonate sediments accumulated in a variety of shallow-marine environments dominated by a northward-sloping ramp, with non-marine, peritidal, lagoonal and coral reef deposition in local areas. The Upper Miocene succession is mainly deeper-water hemipelagic marl with clastic interbeds. Messinian evaporites were deposited near the depocentre. The Early Miocene coarse fluvial sediments above the regional unconformity reflect the development of a flexural bulge, or re-activated basement structure. The Middle Miocene carbonates and Upper Miocene marls are interpreted as the lower and middle units of an “underfilled trinity”, considered typical of peripheral foreland basins. Similar Lower Miocene coarse clastic sediments and Mid-Miocene shallow-water carbonates unconformably overlie the Arabian platform succession c. 75 km to the north, where the succession continues upwards into thick shallow-marine to non-marine terrigenous sediments (upper unit of the “trinity”), sourced from the overthrust load. Comparable coarse clastic sediments are absent from the distal foreland basin in the Hatay area, probably reflecting its more southerly position, structural barriers in the foreland and the westward bypassing of sediment towards the Mediterranean Sea. Regional convergence halted by the end of the Miocene and was followed by strike–slip and westward “tectonic escape”. As a result the Miocene foreland basin was dismembered to form the Plio-Quaternary transtensional Hatay Graben. This like many other foreland basins shows some features which are not accommodated by ideal models of foreland basin evolution.

Tectonic evolution of the South Tethyan ocean: evidence from the Eastern Taurus Mountains (Elaziğ region, SE Turkey)

Abstract Geological information from the Eastern Taurus Mountains, part of the Tethyan (South Neotethyan) suture zone exposed in the Elaziğ region, is used here to test existing tectonic hypotheses and to develop a new tectonic model. Five main tectonic stages are identified: (1) Mid-Late Triassic rifting-spreading of Southern Neotethys; (2) Late Cretaceous northward subduction-accretion of ophiolites and arc-related units; (3) Mid-Eocene subduction-related extension; (4) Early-Mid-Miocene collision and southward thrusting over the Arabian Foreland; (6) Plio-Quaternary, post-collisional left-lateral tectonic escape. During the Late Cretaceous ( c. 90 Ma) northward intra-oceanic subduction generated regionally extensive oceanic lithosphere as the İspendere, Kömürhan, Guleman and Killan ophiolites of supra-subduction zone type. A northward-dipping subduction zone was activated along the northern margin of the ocean basin (Keban Platform), followed by accretion of Upper Cretaceous ophiolites in latest Cretaceous time. As subduction continued the accreted ophiolites and overriding northern margin (Keban Platform) were intruded by calc-alkaline plutons, still during latest Cretaceous time. The northern margin was covered by shallow-marine mixed clastic-carbonate sediments in latest Cretaceous-Early Palaeogene time. Northward subduction during the Mid-Eocene was accompanied by extension of the northern continental margin, generating large fault-bounded, extensional basins that were infilled with shallow- to deep-water sediments and subduction-influenced volcanic rocks (Maden Group). Thick debris flows (‘olistostromes’) accumulated along the oceanward edge of the active margin. The partly assembled allochthon finally collided with the Arabian continental margin to the south during Early-Mid-Miocene time in response to oblique convergence; the entire thrust stack was then emplaced southwards over the downflexed Arabian Foreland. Left-lateral strike-slip (tectonic escape) along the East Anatolian Fault Zone ensued.

Stratigraphy and Palaeobiogeography of Mesozoic Benthic Foraminifera - Part 3

The Adriatic Carbonate Platform (AdCP), was a separate shallowmarine depositional system characterized by a lack of terrigenous input and was connected to Gondwana towards the South via Gavrovo–Tripolitza or Apulia. It existed for approximately 120 MY, from the Early Jurassic Pliensbachian/Toarcian) to the end of the Cretaceous, resulting in a 4000–6500 m thick succession of almost pure carbonates. However, this is part of a thicker (>8000 m) sequence of predominantly carbonate rocks which forms the Karst Dinarides, and was deposited during more than 270 MY – at least from the Carboniferous (Moscovian) to the Late Eocene. Among many different groups of fossil organisms, benthic foraminifera are especially abundant and well preserved, so they, along with calcareous algae (Dasycladales), are the most important fossils used for age determination and stratigraphic subdivision of shallow-marine carbonate deposits. Within the 257 determined taxa belonging to different foraminiferal families which lived through the Mesozoic, numerous different index fossils occur in assemblages indicating various ages: Early Triassic, Anisian, Carnian, Norian–Rhaetian, Late Sinemurian, Early and Late Pliensbachian (Carixian and Domerian), Early and Late Aalenian, Early and Late Bajocian, Early and Late Bathonian, Callovian, Early and Late Oxfordian, Kimmeridgian, Tithonian, Berriasian, Valanginian, Late Hauterivian, Late Barremian, Early and Late Aptian (Bedulian and Gargasian), Early and Late Albian, Early, Middle and Late Cenomanian, Turonian, Coniacian, Santonian, Early and Late Campanian and Early and Late Maastrichtian. A total of 64 biostratigraphic units – biozones of different categories, from subzone to superzone, were defined within the stratigraphic interval from the Carnian to the Late Maastrichtian. This enabled very detailed biostratigraphic subdivision of the carbonate deposits within the Karst Dinarides. This is one of the most precise sequences, not only in this area, but also among former shallow marine deposits of the entire Neotethyan realm in the present Mediterranean region. The palaeobiogeographic characteristics of biotopes and the composition of foraminiferal assemblages during the Mesozoic were controlled by the position of the study area within the Neotethyan bioprovinces. Until the Albian, this area represented part of the Southern Neotethyan bioprovince, while from the Cenomanian to its final disintegration at the end of the Cretaceous it belonged to a separate, Central Mediterranean Neotethyan bioprovince.

Stratigraphy and Palaeobiogeography of Mesozoic Benthic Foraminifera - Part 2

The Adriatic Carbonate Platform (AdCP), was a separate shallowmarine depositional system characterized by a lack of terrigenous input and was connected to Gondwana towards the South via Gavrovo–Tripolitza or Apulia. It existed for approximately 120 MY, from the Early Jurassic Pliensbachian/Toarcian) to the end of the Cretaceous, resulting in a 4000–6500 m thick succession of almost pure carbonates. However, this is part of a thicker (>8000 m) sequence of predominantly carbonate rocks which forms the Karst Dinarides, and was deposited during more than 270 MY – at least from the Carboniferous (Moscovian) to the Late Eocene. Among many different groups of fossil organisms, benthic foraminifera are especially abundant and well preserved, so they, along with calcareous algae (Dasycladales), are the most important fossils used for age determination and stratigraphic subdivision of shallow-marine carbonate deposits. Within the 257 determined taxa belonging to different foraminiferal families which lived through the Mesozoic, numerous different index fossils occur in assemblages indicating various ages: Early Triassic, Anisian, Carnian, Norian–Rhaetian, Late Sinemurian, Early and Late Pliensbachian (Carixian and Domerian), Early and Late Aalenian, Early and Late Bajocian, Early and Late Bathonian, Callovian, Early and Late Oxfordian, Kimmeridgian, Tithonian, Berriasian, Valanginian, Late Hauterivian, Late Barremian, Early and Late Aptian (Bedulian and Gargasian), Early and Late Albian, Early, Middle and Late Cenomanian, Turonian, Coniacian, Santonian, Early and Late Campanian and Early and Late Maastrichtian. A total of 64 biostratigraphic units – biozones of different categories, from subzone to superzone, were defined within the stratigraphic interval from the Carnian to the Late Maastrichtian. This enabled very detailed biostratigraphic subdivision of the carbonate deposits within the Karst Dinarides. This is one of the most precise sequences, not only in this area, but also among former shallow marine deposits of the entire Neotethyan realm in the present Mediterranean region. The palaeobiogeographic characteristics of biotopes and the composition of foraminiferal assemblages during the Mesozoic were controlled by the position of the study area within the Neotethyan bioprovinces. Until the Albian, this area represented part of the Southern Neotethyan bioprovince, while from the Cenomanian to its final disintegration at the end of the Cretaceous it belonged to a separate, Central Mediterranean Neotethyan bioprovince.

Stratigraphy and Palaeobiogeography of Mesozoic Benthic Foraminifera - Part 1

The Adriatic Carbonate Platform (AdCP), was a separate shallowmarine depositional system characterized by a lack of terrigenous input and was connected to Gondwana towards the South via Gavrovo–Tripolitza or Apulia. It existed for approximately 120 MY, from the Early Jurassic Pliensbachian/Toarcian) to the end of the Cretaceous, resulting in a 4000–6500 m thick succession of almost pure carbonates. However, this is part of a thicker (>8000 m) sequence of predominantly carbonate rocks which forms the Karst Dinarides, and was deposited during more than 270 MY – at least from the Carboniferous (Moscovian) to the Late Eocene. Among many different groups of fossil organisms, benthic foraminifera are especially abundant and well preserved, so they, along with calcareous algae (Dasycladales), are the most important fossils used for age determination and stratigraphic subdivision of shallow-marine carbonate deposits. Within the 257 determined taxa belonging to different foraminiferal families which lived through the Mesozoic, numerous different index fossils occur in assemblages indicating various ages: Early Triassic, Anisian, Carnian, Norian–Rhaetian, Late Sinemurian, Early and Late Pliensbachian (Carixian and Domerian), Early and Late Aalenian, Early and Late Bajocian, Early and Late Bathonian, Callovian, Early and Late Oxfordian, Kimmeridgian, Tithonian, Berriasian, Valanginian, Late Hauterivian, Late Barremian, Early and Late Aptian (Bedulian and Gargasian), Early and Late Albian, Early, Middle and Late Cenomanian, Turonian, Coniacian, Santonian, Early and Late Campanian and Early and Late Maastrichtian. A total of 64 biostratigraphic units – biozones of different categories, from subzone to superzone, were defined within the stratigraphic interval from the Carnian to the Late Maastrichtian. This enabled very detailed biostratigraphic subdivision of the carbonate deposits within the Karst Dinarides. This is one of the most precise sequences, not only in this area, but also among former shallow marine deposits of the entire Neotethyan realm in the present Mediterranean region. The palaeobiogeographic characteristics of biotopes and the composition of foraminiferal assemblages during the Mesozoic were controlled by the position of the study area within the Neotethyan bioprovinces. Until the Albian, this area represented part of the Southern Neotethyan bioprovince, while from the Cenomanian to its final disintegration at the end of the Cretaceous it belonged to a separate, Central Mediterranean Neotethyan bioprovince.

A Critical Review of The Anatolian Geology: A Dialectic To Sutures and Evolution Of The Anatolian Tethys and Neotethys

A progressively improving hypothesis of evolution for the Anatolian Tethys and Neotethys will be presented in this paper. The Tethyan, the Western (Bursa-Ýzmir-Antalya zone) and the southern Neotethyan sutures will be substantiated after a discussion on the controversial aspects of the Anatolian geology. The initia- tion of the Tethys in Cambrian is supported on the basis of continous Palaeozoic sedimentation on north-facing Gondwanian and south-facing Eurasian platforms. A thin continental sliver, the Apula-Anatolia, started to rift off northern Gondwana in the Early Triassic coevally with the onset of the northward Tethyan subduction. The mar- ginal ophiolites have obducted onto the Pontian active margin by the Middle Triassic as the consequence of the dextral rotation of Western Pontides. The compressional and dilatational fields have shifted oceanward due to a recess (?) of the subduction zone. The positive area covering most of the central and northern Sakarya has col- lapsed progressively and has been onlapped peripherically from the Liassic onwards. The Anatolian microconti- nent detached off Africa in the Upper Triassic-Liassic and drifted northward during the Jurassic and the Cretaceous and collided incipiently with the Eurasian margin (Pontides) in the Upper Cretaceous. Unsubducted pockets of ocean floor have closed with consequent syn-collisional magmas in the Paleogene. The Salt Lake pocket, the East Anatolia and the Western Neotethys, the Intra-Gondwanian rift separating the Anatolia from Apulia-Greece, have survived until the Late Miocene.

Contrasting modes of ophiolite emplacement in the Eastern Mediterranean region

Abstract The Eastern Mediterranean region is characterized by one of the largest concentrations of ophiolites anywhere in the world. Many of these ophiolites are fragmentary or highly deformed, such that their initial mode of tectonic emplacement cannot easily be inferred from the local field relations. The emplacement of many of these ophiolites can usefully be compared with the intact Oman ophiolite, one of the largest and best-studied ophiolites in the world. The Oman ophiolite is commonly believed to have been created in Late Cretaceous time (c. 95 Ma) above an oceanward-dipping, intra-oceanic subduction zone. This was followed by collision of the subduction zone with the downflexed Arabian passive margin, facilitating the emplacement of the ophiolite onto the continental margin. A less likely alternative is that the Oman ophiolite formed at a mid-ocean ridge that then collapsed, initiating the emplacement of the ophiolite. An Oman-type model is applicable to many of the Mid-Jurassic and the Late Cretaceous ophiolites of the Eastern Mediterranean region that were thrust over former passive continental margins. These ophiolites are again mainly of suprasubduction-zone type. Such ophiolites include many of the Jurassic ophiolites of Greece, Albania and former Yugoslavia, and also the Late Cretaceous ophiolites of Turkey and northern Syria. These ophiolites were emplaced from both more northerly and southerly Neotethyan ocean basins. In contrast, the opposing (northerly) margins of these oceanic basins experienced a history of subduction-accretion, marginal arc volcanism and back-arc basin formation ('Cordilleran-type' ophiolites). Ophiolites that were emplaced associated with active margin settings range from large accreted thrust sheets to small slices within accretionary prisms and back-arc basins. Examples include the Late Cretaceous ophiolites that are related both to the northern margin of the southern Neotethys and to the northern margin of the northern Neotethys in Turkey. Not all ophiolites were emplaced in response to large-scale horizontal tectonic transport (e.g. Jurassic Guevgueli ophiolite, northern Greece), and several ophiolites experienced dominantly strike-slip or transpression (e.g. the Late Cretaceous Antalya ophiolites, SW Turkey). In general, the mode of ophiolite emplacement, especially the direction of emplacement relative to the orientation of the adjacent continental margin was influenced by the regional palaeogeographical setting.

Palaeomagnetic insights into the evolution of Neotethyan oceanic crust in the eastern Mediterranean

Abstract A synopsis of palaeomagnetic data from three Late Cretaceous eastern Mediterranean Tethyan ophiolites (Troodos, Hatay and Baër-Bassit) and their sedimentary cover sequences is presented. These data provide valuable insights into the role of regional- and local-scale tectonic rotations in the geodynamic evolution of Neotethyan oceanic crust. The geologically earliest phases of tectonic rotation are documented in the Troodos ophiolite, where rotations around both subvertical and subhorizontal axes are readily related to the development of the spreading fabrics and structures during crustal genesis. Subsequent c. 74° antickockwise intra-oceanic rotation of a ‘Troodos microplate’ has been quantified through analysis of the in situ sedimentary cover of the Troodos ophiolite. Results indicate that bulk anticlockwise rotation began soon after the cessation of spreading and ended by the end of the Eocene, with c. 50–60° of microplate rotation being over by the Maastrichtian, the time at which ophiolite thrust sheets were emplaced onto the Arabian continental margin to the east of Troodos. Recent results from the emplaced, structurally dismembered Baër-Bassit ophiolite indicate extreme anticlockwise rotations of ophiolitic thrust sheets varying on a kilometre scale. New data from the post-emplacement sedimentary cover confirm that only a small component of these rotations is due to post-emplacement tectonism. Baër-Bassit represents the leading edge of the emplaced ophiolitic sheet. New data from the more coherent section preserved in the Hatay ophiolite to the north demonstrate significant anticlockwise rotation. This is equivalent to the rotation of the most northerly part of the Baër-Bassit units to the south, and is of the same sense and magnitude as the pre-Maastrichtian phase of microplate rotation documented in the Troodos. This suggests a common, intra-oceanic origin for the majority of the Troodos and Hatay rotations, and a significant component of the more variable rotations observed in Baër-Bassit. Overall, therefore, the data support a model involving: (1) intra-oceanic rotation of a coherent region of crust within the southern Neotethyan basin; this rotated unit is more areally extensive than has previously been inferred from consideration of data from the Troodos ophiolite alone; (2) emplacement of part of the rotated unit onto the Arabian platform; (3) subsequent localized post-emplacement modification, related to the development of the current plate configuration.