The fifteen chapters included in this volume are concerned with the main issues in the Eastern Black sea and Caucasus regions of the Alpine–Tethyan orogenic realm, which are: (1) the changes in space and time of geodynamic processes responsible for the closure of the northern branch of the Neotethys Ocean and how these changes are related to the opening and inversion of back-arc basins; (2) the northwestern terminus of the Eastern Black sea rift; (3) timing and evolution of inverted and foreland basins; (4) the continuity of structures and their evolution in time between the Eastern Black Sea, the Greater Caucasus, the Lesser Caucasus and those of the Taurides–Anatolides– Pontides belt and of NW Iran; and (5) Paratethys evolution since the Eocene in this belt. The papers included in this volume present new results obtained mostly by projects supported by the DARIUS programme.

This wide area of the Alpine-Himalayan belt evolved through a series of tectonic events related to the opening and closure of the Tethys Ocean. In doing so it produced the largest mountain belt of the world, which extends from the Atlantic to the Pacific oceans. The basins associated with this belt contain invaluable information related to mountain building processes and are the locus of rich hydrocarbon accumulations. However, knowledge about the geological evolution of the region is limited compared to what they offer.

Southwest Asia is one of the most remarkable regions on Earth in terms of active faulting and folding, large-magnitude earthquakes, volcanic landscapes, petroliferous foreland basins, historical civilizations as well as geologic outcrops that display the protracted and complex 540 m.y. stratigraphic record of Earth's Phanerozoic Era. Emerged from the birth and demise of the Paleo-Tethys and Neo-Tethys oceans, southwest Asia is currently the locus of ongoing tectonic collision between the Eurasia-Arabia continental plates. The region is characterized by the high plateaus of Iran and Anatolia fringed by the lofty ranges of Zagros, Alborz, Caucasus, Taurus, and Pontic mountains; the region also includes the strategic marine domains of the Persian Gulf, Gulf of Oman, Caspian, and Mediterranean. This 19-chapter volume, published in honor of Manuel Berberian, a preeminent geologist from the region, brings together a wealth of new data, analyses, and frontier research on the geologic evolution, collisional tectonics, active deformation, and historical and modern seismicity of key areas in southwest Asia.

The Black Sea remains one of the largest underexplored rift basins in the world. Future success is dependent on a better understanding of a number of geological uncertainties. These include reservoir and source rock presence and quality, and the timing of migration of hydrocarbons relative to trap formation. An appreciation of the geological history of the Black Sea basins and the surrounding orogens is therefore key. The timing of basin formation, uplift of the margins, and of facies distribution remain issues for robust debate. This Special Publication presents the results of 15 studies that relate to the tectono-stratigraphy and petroleum geology of the Black Sea. The methodologies of these studies encompass crustal structure, geodynamic evolution, stratigraphy and its regional correlation, petroleum systems, source to sink, hydrocarbon habitat and play concepts, and reviews of past exploration. They provide insight into the many ongoing controversies concerning Black Sea regional geology and provide a better understanding of the geological risks that must be considered for future hydrocarbon exploration.

The Greater Caucasus Mountains, located between the Black and Caspian Seas at the northern margin of the Arabia-Eurasia collision zone, presently accommodate most (70%) of the orogen-perpendicular shortening within this sector of the collision zone. However, the structural geometry and tectonic evolution of this range remain poorly constrained. The core of the Greater Caucasus is predominantly made up of marine sedimentary rocks that represent a Mesozoic-age basin that has been tectonically inverted over the last ~35 Ma. The width of this marine basin, the timing of its closure, and the total amount of shortening accommodated during its closure are debated. Multiple models have been proposed for the tectonic evolution of the Greater Caucasus Mountains, including pure-shear thickening of primarily continental crust, inversion of rift-related extensional structures to close a back-arc basin, and marine basin closure through subduction ultimately concluding with continental collision, subduction termination, and slab breakoff. Specifically, patterns in exhumation, shortening rate, and subcrustal seismicity along strike of the range support the model that the modern range may record ongoing subduction termination and slab breakoff, with an along-strike transition from an attached subducted slab in the east to a detached slab in the west. However, the structural architecture of the range and shortening rates across the orogen are not well constrained. The competing models explaining Greater Caucasus evolution make specific predictions for the geology exposed within the range and. For example, the subduction and slab breakoff model for the evolution of the Greater Caucasus requires that the back-arc basin was at least several hundred kilometers wide. Investigation of the stratigraphy and structural geology exposed in the core of the range is therefore critical to evaluating the slab breakoff model against alternative models of Greater Caucasus evolution. We combine 1:100k structural mapping along two orogen-perpendicular transects with stratigraphic and structural analyses to constrain the magnitude of shortening accommodated within the Greater Caucasus, and thus the minimum width of the Greater Caucasus ocean basin prior to basin closure and continental collision. Using these data, we find that balanced geologic cross sections of the western and central Greater Caucasus (along the Enguri and Aragvi Rivers, respectively) indicate a minimum of ~200 km of total shortening since exhumation of the orogen began. This estimate is a minimum, because it does not account for non-accretionary underthrusting. These magnitudes of shortening are similar to those expected for subduction/ slab breakoff, and exceed those expected for buoyancy-driven uplift. In addition, they are comparable to estimates of total shortening within the Greater Caucasus derived from paleomagnetic data. The subduction termination and slab breakoff model also predicts a change in shortening rate through time, as the subducting slab detaches, the marine basin closes, and the convergent margin transitions into a continental collision. We estimate the long-term (last ~30 My) shortening rate for the western Greater Caucasus by combining total shortening from balanced cross sections within the orogen and timing of initiation of exhumation and uplift as, and calculate a minimum shortening rate of 6-8 mm/yr. We compare this long-term geologic shortening rate with the shortening rate across active structures in the modern Greater Caucasus. Deformed river terraces along the antecedent Enguri River in the western Greater Caucasus allow us to quantify Quaternary deformation across the Rioni Basin fold/thrust belt (RFTB). We integrate surficial and bedrock geologic mapping and topographic surveys to build a kinematic model describing both terrace deformation and the finite deformation recorded by underlying folded late Neogene strata within the Dzumi fold. Luminescence dates from 3 samples in a loess cap on a folded terrace give a maximum age for terrace abandonment of 94.1 ± 12.8 ky. Monte Carlo simulations accounting for uncertainties in fold geometry indicate 151 +65/-27 m of displacement since formation of the folded terrace, implying an average shortening rate of 1.6 +1.5/-0.6 mm/yr over the past ~100 ky. The magnitudes of shortening and rates we find in the RFTB are consistent with modern geodetic shortening rates across the western Greater Caucasus, which range from 0-4 mm/yr. This apparent discrepancy between short- and long-term shortening rates can be explained by a change in shortening rate over time. A decrease in shortening rate over time has been predicted as a result of the subduction and slab breakoff model of Greater Caucasus evolution. The Greater Caucasus may thus offer insights into the geologically ephemeral response to the transition from subduction to collision, and how that transition is recorded in the surface geologic record.