Abstract Before the Late Cretaceous opening of the Black Sea, the Central Pontides constituted part of the southern margin of Laurasia. Two features that distinguish the Central Pontides from the neighbouring Pontide regions are the presence of an extensive Lower Cretaceous submarine turbidite fan (the Çağlayan Formation) in the north, and a huge area of Jurassic–Cretaceous subduction–accretion complexes in the south. The Central Pontides comprise two terranes, the Istanbul Zone in the west and the Sakarya Zone in the east, which were amalgamated before the Late Jurassic (Kimmeridgian), most probably during the Triassic. The basement in the western Central Pontides (the Istanbul Zone) is made up of a Palaeozoic sedimentary sequence, which ends with Carboniferous coal measures and Permo-Triassic red beds. In the eastern Central Pontides, the basement consists of Permo-Carboniferous granites and an Upper Triassic forearc sequence of siliciclastic turbidites with tectonic slivers of pre-Jurassic ophiolite (the Küre Complex). The Küre Complex is intruded by Middle Jurassic granites and porphyries, which constitute the western termination of a major magmatic arc. Upper Jurassic–Lower Cretaceous shallow-marine limestones (the İnaltı Formation) lie unconformably over both the Istanbul and Sakarya sequences in the Central Pontides. Two new measured stratigraphic sections from the İnaltı Formation constrain the age of the İnaltı Formation as Kimmeridgian–Berriasian. After a period of uplift and erosion during the Valanginian and Hauterivian, the İnaltı Formation is unconformably overlain by an over 2 km-thick sequence of Barremian–Aptian turbidites. Palaeocurrent measurements and detrital zircons indicate that the major part of the turbidites was derived from the East European Platform, implying that the Black Sea was not open before the Aptian. The Çağlayan turbidites pass northwards to a coeval carbonate–clastic shelf exposed along the present Black Sea coast. In the southern part of the Central Pontides, the Lower Cretaceous turbidites were deformed and metamorphosed in the Albian. Albian times also witnessed accretion of Tethyan oceanic crustal and mantle sequences to the southern margin of Laurasia, represented by Albian eclogites and blueschists in the Central Pontides. A new depositional cycle started in the Late Cretaceous with Coniacian–Santonian red pelagic limestones, which lie unconformably over the older units. The limestones pass up into thick sequences of Santonian–Campanian arc volcanic rocks. The volcanism ceased in the middle Campanian, and the interval between late Campanian and middle Eocene is represented by a thick sequence of siliciclastic and calciclastic turbidites in the northern part of the Central Pontides. Coeval sequences in the south are shallow marine and are separated by unconformities. The marine deposition in the Central Pontides ended in the Middle Eocene as a consequence of collision of the Pontides with the Kırşehir Massif. Supplementary material: The palaeontological data (foraminifera, nannofossil and pollen) are available at: https://doi.org/10.6084/m9.figshare.c.3842359

Abstract New data for regionally important granulite facies metaophiolitic rocks and cross-cutting granitoids rocks are presented and discussed. The high-temperature/high-pressure Berit metaophiolite is cut by unmetamorphosed Eocene (51–45 Ma) granitoid rocks. The highest metamorphic grade occurs in blocks of mafic granulites. Enveloping amphibolite facies rocks reflect retrograde metamorphism related to exhumation. Sm–Nd (pyroxene–garnet–amphibole–whole rock) isochron ages of 52–50 Ma for the granulite facies rocks are interpreted to represent the time of cooling of the granulite facies rocks. The over-riding Malatya metamorphic unit to the north is also intruded by Eocene granitoid rocks. The granulite facies metamorphism of the meta-ophiolitic rocks is inferred to have formed in the roots of an Eocene magmatic arc, with accentuated heat flow being provided by subduction of a spreading ridge, or rupture of the subducting slab. The high-temperature/high-pressure metamorphism was followed by exhumation, as indicated by field structural relations and the evidence of retrograde metamorphism. The Eocene arc magmatism can best be explained by northward subduction of the Southern Neotethys, which persisted after the time of latest Cretaceous regional ophiolite emplacement until the collision of the Eurasian (Anatolian) and Arabian continents during the Early–Mid Miocene. Subsequent Plio-Quaternary left-lateral strike-slip strongly affected the area. Supplementary-material: Four supplementary tables giving the whole rock geochemistry of the granitoids, mineral geochemistry of the granulite facies rocks, LA-MC-ICP-MS zircon U–Pb data belonging to granitoids and Sm–Nd data belonging to granulite facies rocks and two documents giving the detailed analytical procedures and detailed petrography of the granitoids are available at http://www.geolsoc.org.uk/SUP18588

Abstract The Black Sea is a 423,000-km 2 (163,000-mi 2 )-large Cretaceous-Tertiary basin surrounded by Alpine fold belts. It consists mainly of two large subbasins separated by the northwest-southeast-trending mid-Black Sea ridge (Figure 1 ). The west Black Sea basin is floored by oceanic crust overlain by more than 3-km (1.8-mi)-thick flat-lying sediments probably of Cretaceous and younger age ( Letouzey et al., 1977 ; Finetti et al., 1988 ; Okay et al., 1994 ; Robinson, 1996 ). Thenorthwest-trending east Black Sea basin has a thinned continental or oceanic crust overlain by less than 10-km (6-mi)-thick sediments, which are intersected by a large number of faults. It is generally accepted that the Black Sea opened during the Mesozoic as a back-arc basin above the northward-subducting Tethyan oceanic lithosphere (e.g., Bocceletti et al., 1974 ; Şengör and Yilmaz, 1981 ). A kinematic model for the opening of the Black Sea, based largely on data from onshore areas, was suggested in 1994 by Okay et al. The model involved separate mechanisms for the origin of the west and east Black Sea basins. The west Black Sea basin was believed to have opened by orthogonal rifting of a continental fragment from the odessa shelf starting in the Albanian-Cenomonian ( Okay et al., 1994 ). This continental fragment, called the Istanbul zone (Figure 1 ), drifted south, bounded by two major strike-slip faults, opening the oceanic west Black Sea basin in the north and closing the Tethyan Ocean in the south (Figure 2 ). During the early Eocene, the Istanbul zone collided with the Sakarya zone in the south, thereby causing a change-over from extension to compression in the Black Sea. Okay et al. (1994) suggested that the eastern half of the Black Sea, including the east Black Sea basin, mid-Black Sea ridge, and the easternmost part of the west Black Sea basin (Figure 1 ), opened through the anticlockwise rotation of a large continental block around a pole situated in Crimea (Figure 2 ). Such a mode of opening explained the Tertiary compression in the Caucasus, which diminishes northwestward toward the pole of rotation, as well as the segmented southern boundary of the eastern Black Sea. The rotation was believed to have been contemporaneous with the rifting in the west Black Sea basin (Figure 2 ).

Abstract A belt of Late Triassic deformation and metamorphism (Cimmeride Orogeny) extends east-west for 1100 km in northern Turkey. It is proposed that this was caused by the collision and partial accretion of an Early-Middle Triassic oceanic plateau with the southern continental margin of Laurasia. The upper part of this oceanic plateau is recognized as a thick Lower-Middle Triassic metabasite-marble-phyllite complex, named the Nilüfer Unit, which covers an area of 120 000 km 2 with an estimated volume of mafic rocks of 2 × 10 5 km 3 . The mafic sequence, which has thin stratigraphic intercalations of hemipelagic limestone and shale, shows consistent within-plate geochemical signatures. The Nilüfer Unit has undergone a high-pressure greenschist facies metamorphism, but also includes tectonic slices of eclogite and blueschist with latest Triassic isotopic ages, produced during the attempted subduction of the plateau. The short period for the orogeny (< 15 Ma; Norian-Hettangian) is further evidence for the oceanic plateau origin of the Cimmeride Orogeny. The accretion of the Nilüfer Plateau produced strong uplift and compressional deformation in the hanging wall. A large and thick clastic wedge, fed from the granitic basement of the Laurasia, represented by a thick Upper Triassic arkosic sandstone sequence in northwest Turkey, engulfed the subduction zone and the Nilüfer Plateau.

Abstract The 500-km-long Eastern Pontide belt shows several common Stratigraphic features resulting from a common Mesozoic-Tertiary tectonic history. There is a heterogeneous pre-Jurassic basement comprised of Devonian? high-grade metamorphic rocks, Lower Carboniferous granodiorites and dacites, Upper Carboniferous-Lower Permian shallow-marine to terrigeneous sedimentary rocks and an allochthonous Permo-Triassic metabasite-phyllite-marble unit. The Mesozoic sedimentary sequence starts with a widespread Liassic marine transgression coming from the south. The Lower and Middle Jurassic rocks of the Eastern Pontides make up a 2000-m-thick sequence of tuff, pyroclastic rock, lava, and interbedded clastic sedimentary rock; the volcanism is proba-bly related to rifting leading to the opening of the Neotethyan Ocean in the south. The Upper Jurassic-Lower Cretaceous is characterized by carbonates, showing a transition from platform carbonate deposition in the north to pelagic carbonates and calciturbidites in the south; this indicates the develop-ment of a south-facing passive continental margin. During the Cenomanian, there was uplift and erosion throughout the Eastern Pontides. Rocks of this stage are not present, and in many localities the Senonian deposits lie uncon-formably over Jurassic carbonates and even over the Carboniferous granitic basement. This compressive event is associated with the northward emplace-ment of an ophiolitic melange over the passive continental margin of the Eastern Pontides. The obduction of the ophiolitic melange is probably caused by the partial subduction of the Eastern Pontides continental margin in a south-dipping intra-oceanic subduction zone. This was followed by the flip of the subduction polarity during the Cenomanian-Turonian, which led to the development of a Senonian volcanic arc in the outer Eastern Pontides above the northward-subducting Tethyan Ocean floor. The volcanic arc is represent-ed by >2-km-thick succession of volcanic and volcaniclastic rocks and interbedded limestones and marls. There are also intrusive granodiorite plu- tons with isotopic ages of 95 to 65 m.y. The volcanism shows a general silica enrichment, with time, ranging from basalts and andesites to dacites. The Senonian sequence in the inner Eastern Pontides is made up of a tuffaceous flyschoid series representing the fore-arc succession. The Eastern Black Sea Basin probably opened during the Maastrichtian through the rifting of the volcanic arc axis. During the late Paleocene-early Eocene, there was north-vergent thrust imbrication of the inner Eastern Pontides with the development of a major foreland flysch basin in front of the northward moving thrust sheets. Folding and uplift occurred in the outer Eastern Pontides during this period. This compressive deformational event, the strongest Mesozoic-Tertiary orogenic phase in the Eastern Pontides, was probably caused by the collision between the Pontide arc and the Tauride microplate in the south. Widespread calc-alkaline volcanism and shallow-marine sedimentation occurred throughout the Eastern Pontides during the middle Eocene. The middle Eocene rocks are essentially undeformed and lie unconformably over a folded and thrust-faulted basement. This major middle Eocene extensional event is probably related to an accelarated phase of opening of the Eastern Black Sea Basin. From the end of the middle Eocene onward, the Eastern Pontides stayed largely above sea level, with minor volcanism and terrigeneous sedimentation.