The Eocene uplift and inversion of a part of the Black Sea margin in the Central Pontides, allows to study the stratigraphic sequence of the Western Black Sea Basin. The revision of this sequence, with 164 nannoplankton ages, indicates that subsidence and rifting started in the Upper Barremian and accelerated during the Aptian. The rifting of the Western Black Sea Basin lasted about 40 Myr (from late Barremian to Coniacian). In the inner, inverted, Black Sea margin, the syn-rift sequence ends up with shallow marine sands. The uppermost Albian to Turonian was a period of erosion or non deposition. This regional mid-Cretaceous stratigraphical gap might result from rift flank uplift, as expected in the case of a thick and cold pre-rift lithosphere. However, coeval collision of the Kargi Block, along the North Tethyan subduction zone at the southern margin of the Pontides, might also have contributed to this uplift. A rapid thermal post-rift subsidence of the margin occurred during the Coniacian-Santonian. Collision of the Kirşehir continental block commenced in Early Eocene time (zone NP12) giving rise to compressional deformation and sedimentation in piggyback basins in the Central Pontides, whereas the eastern Black Sea was still opening.

Oblique and normal fault systems exposed in the Büyük Menderes Graben (BMG) region record two successive and independent complex tectonic events. The first group tectonic event is defined by an E–W extension related to N–S contraction and transpression. This group is responsible for the development of NW- and NE-trending conjugate pairs of oblique faults which controlled Early–Middle Miocene basin formation. Between the Early–Middle Miocene and Plio-Quaternary strata exists an unconformity, indicating a period of folding, uplift and severe erosion associated with N–S shortening. The second group of events was the change in tectonic regime from E–W extension to N–S extension which controlled the formation of the Büyük Menderes Graben by three progressive pulses of deformation. The first pulse of extensional deformation was initially recorded in the region by the exhumation of the deep part of the Menderes Massif (MM) with the development of the E-trending Büyük Menderes Detachment Fault (BMDF). The minimum age of this pulse is constrained by the older Plio-Quaternary fluviatile deposits of the Büyük Menderes Graben that range in age from the Plio-Pleistocene boundary interval to Late Pleistocene. The second pulse, which is marked by the rapid deposition of alluvial deposits, initiated the formation of approximately E–W-trending high-angle normal faults synthetic and antithetic to the Büyük Menderes Detachment Fault, on the northern margin during Holocene times. These faults are interpreted as secondary steeper listric faults that merge with the main Büyük Menderes Detachment Fault at depth. The third pulse was the migration of the Büyük Menderes Graben depocentre to the present day position by diachronous activity of secondary steeper listric faults. These steeper faults are the most seismically active tectonic elements in western Turkey. According to the stratigraphic and structural data, the N–S extension in the Büyük Menderes Graben region produced a progressive deformation phase with different pulses during its Plio-Quaternary evolution, with migration of deformation from the master fault to the hangingwall. The formation of diachronous secondary synthetic and antithetic steeper faults on the upper plate of the Büyük Menderes Detachment Fault, hence the southward migration of the deformation and of the Büyük Menderes Graben depocentre, should be related to the evolution of detachment in the region. The presence of the seismically active splays of secondary faults implies an active detachment system in the region. This young Plio-Quaternary N–S extension in the Büyük Menderes Graben may be attributed to the combined effects of the two continuing processes in Aegean region. The first process is back-arc spreading or probably the roll-back of African slab below the south Aegean Arc, which seems to be responsible for the change in the stress tensor from E–W extension to N–S extension. The second and later event is the southwestward escape of the Anatolian block along its boundary fault, that is, the North Anatolian fault (NAF).

To illustrate the structural evolution of the Black Sea Basin in the context of Neotethyan subduction and subsequent continental collisions, we present the fi rst lithosphere-scale, ~250-km-long, balanced and restored cross section across its southern continental margin, the Central Pontides. Cross-section construction and restoration are based on fi eld, seismic-refl ection, geophysical, and apatite fi ssion-track data. The structure of the onshore Pontides belt is predominantly controlled by inverted normal faults, whereas the offshore areas are devoid of large structural inversion. The restored section indicates that Cretaceous crustal thinning occurred synchronously with (probably buoyancydriven) exhumation of a forearc high-pressure blueschist wedge likely during Neotethyan slab retreat. Apatite fi ssion-track data show that structural inversion of the forearc zone, which formed the Central Pontides fold-and-thrust belt, started at ca. 55 Ma. This Eocene structural inversion followed upon collision of the Kırşehir continental block and the arrest of Neotethyan oceanic subduction below the Central Pontides. Compared to the Central Pontides belt, which underwent signifi cant shortening (~28 km, i.e., ~33%), the relatively colder and stronger Black Sea lithosphere prevented the northern offshore areas from undergoing inversion. We propose that the location of Cenozoic contractional deformation is related to the absence of lithospheric mantle below the southern Pontides (forearc) zone as a consequence of the Cretaceous high-pressure wedge exhumation.

the Pontides by the Kırşehir continental block to the south, with 27.5 km (~28 %) shortening along the section studied. The inversion was characterized by NNE-trending shortening that predated the Late Neogene dextral escape of Anatolia along the North Anatolian Fault and the modern stress field characterized by NW-trending compression within the Eocene Boyabat basin.

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