Abstract This chapter presents schematic reconstructions of the Black Sea region in Triassic to Cretaceous time. The tectonic evolution of the region during this time was controlled by the northward subduction of the Tethys oceanic plate. The ocean is now closed at a suture extending from Romania to the Aegean and through the whole length of northern Turkey to Iran. The overriding European plate was alternately subjected to extensional and compressive deformation and arc magmatism, resulting in a zone of considerable structural and Stratigraphie complexity The present Western Black Sea opened in the mid-Cretaceous as the microplate comprising what is now the Western and Central Pontides separated from the Moesian and Scythian platforms and moved southeast to leave an oceanic back-arc basin behind it. We identify two regional strike-slip transfer fault zones that constrained the movement of the Pontide microplate. Our restoration enables us to recognize the Peceneaga-Camena fault and its extensions as a key tectonic feature—another major transfer fault—in the earlier Triassic and Jurassic events. We suggest that its displacement was sinistral in the Late Triassic–Early Jurassic, with Moesia moving southeast, leaving an oceanic embayment now occupied by the Pannonian Basin. This phase was generally transtensional, opening a string of back-arc basins in the Black Sea area, which then closed in the Middle–Late Jurassic Cimmeride orogeny.

Abstract Three minor thrust belts are abruptly terminated at the Balkan coast of the Black Sea: the Strandzhides of Thrace and Bulgaria, the Balkanides of central Bulgaria, and the North Dobrogea belt of Romania. The Strandzhides are the eastern external zones of the Rhodope Massif and were the site of a south-facing continental margin that started as a pas-sive margin in the Triassic, but soon became active. The major compression was in the Late Jurassic, and the belt is made up of at least four large thrust nappes, with large displacements. The foreland basin, if it exists at all, is now buried by a Late Cretaceous magmatic arc. The Balkanides are a narrow thrust belt involving Mesozoic-Paleogene stratigraphy that is remarkably different from south to north of the belt. The area was affected by extension, mainly in the late Triassic and early-mid Cretaceous (when the Western Black Sea opened). It was not seriously compressed until the Eocene, at which time a narrow foreland basin formed due to thrust loading of the otherwise stable Moesian Platform. North Dobrogea is an enigmatic zone separating Moesia from the Eastern European Platform. It was highly extended during the Triassic, and then compressed, probably transpressively, in the Late Jurassic. The Mesozoic-Paleogene tectonic history of the Balkans was controlled by the northward subduction of the Vardar oceanic plate (a branch of Tethys) from the Mid-Late Triassic until its closure in the Eocene. It is suggested that North Dobrogea marks a major crustal boundary at the northern limit of back-arc deformation, where the Moesian Platform was displaced SE by a distance of several hundred kilometers during the Late Triassic to Early Jurassic. The Strandzhides and Balkanides constituted a mobile active margin of the overriding Moesian-European Plate, which was alternately extended (Triassic and Cretaceous) and compressed (Jurassic/Cimmeride and Paleogene/ Alpide), so that the area has become a mosaic of extensional and compressive structural elements.

Abstract This chapter describes the geology of Georgia and the Georgian part of the Black Sea. It is based on geological maps and seismic interpretation, integrated with well data and outcrop studies. The geology of Georgia consists of two major thrust belts: the Greater Caucasus and the Achara-Trialet belt, separated by two foreland basins (Rioni and Kartli) with an intervening basement culmination, the Dziruli Massif. The Achara-Trialet belt comprises a thick Upper Cretaceous and Paleogene sequence that restores to a rift and postrift basin of probable Paleocene age, connecting to the Eastern Black Sea. The basin began to close by the Oligocene. Structures are detached at Aptian and Oligocene levels and are large and open. The Rioni Basin developed mainly during the Oligocene and the Miocene through loading by the Achara-Trialet belt folds. It dies out into the Eastern Black Sea as the foreland basin megasequence merges with the postrift fill of the latter. North of the Rioni Basin, the major thrust front is a large south-dipping monocline, in front of which there are extensive salients detached in Upper Jurassic evaporites. The Kartli Basin passes into the Kura Basin to the east, where the foreland basin is deformed by the Greater Caucasus south-vergent thrust structures.