Abstract Oligocene and Lower Miocene deposits in the Paratethys are important source rocks, but reveal major stratigraphic and regional differences. As a consequence of the first Paratethys isolation, source rocks with very good oil potential accumulated during Early Oligocene time in the Central Paratethys. Coeval source rocks in the Eastern Paratethys are characterized by a lower source potential. With the exception of the Carpathian Basin and the eastern Kura Basin, the source potential of Upper Oligocene and Lower Miocene units is low. In general, this is also valid for rocks formed during the second (Kozakhurian) isolation of the Eastern Paratethys. However, upwelling along a shelf-break canyon caused deposition of prolific diatomaceous source rocks in the western Black Sea. Overall, Oligocene–Lower Miocene sediments in the Carpathian Basin (Menilite Formation) can generate up to 10 t HC m −2 . Its high petroleum potential is a consequence of the interplay of very high productivity of siliceous organisms and excellent preservation in a deep silled basin. In contrast, the petroleum potential of Oligocene–Lower Miocene (Maikopian) sediments in the Eastern Paratethys is surprisingly low (often <2 t HC m −2 ). It is, therefore, questionable whether these sediments are the only source rocks in the Eastern Paratethys.

Abstract This study comprises the source rock evaluation of 122 Late Middle Eocene–Early Miocene mudstones from the NE margin of the Black Sea. Samples are immature to early mature. The majority of samples have moderate to very good organic richness, poor to moderate source potential and a hydrogen-deficient to gas-prone source rock quality. However, a significant proportion of the samples have good to excellent organic richness and source potential, and an oil- and gas-prone quality derived from amorphous-rich kerogens. These samples would generate significant amounts of oil and associated gas where buried to peak maturity. They come from the lowermost (Rupelian) part of the Maykop Series and the late Bartonian–early Priabonian Kuma Suite or its stratigraphic equivalents. The Rupelian source-rock interval(s) in west Georgia is at least 60 m thick and potentially as much as 200 m thick. It has a source potential index (SPI) of 0.7–2.5 t HC m −2 . The thickness of the Kuma Suite-equivalent source rock interval south of the western Greater Caucasus is unconstrained. Maykop Series source rocks occur in the Black Sea Basin. Prospective Kuma Suite-equivalent samples on both the northern and southern margins of the Black Sea imply that similar sediments may also be present in the basin. Supplementary material: Additional information on the geographical location and age determination of the samples discussed in this paper are available at https://doi.org/10.6084/m9.figshare.c.3841399

Abstract The Rioni Basin is an underexplored petroliferous basin located at the Georgian margin of the Black Sea flanked by two folded belts (the Greater Caucasus and the Achara–Trialet Belt). Whereas the stratigraphy of the northern onshore Rioni Basin has elements which are common with that of the offshore Shatsky Ridge, the southern onshore Rioni Basin segment is both stratigraphically and structurally akin to the offshore Gurian folded belt in the eastern Black Sea. In the northern basin segment, the existing oil fields (East and West Chaladidi) and an undeveloped oil discovery (Okumi) are related to either post-salt or pre-salt antiformal traps in detachment folds or in poorly understood stratigraphic pinchouts beneath a regional Upper Jurassic evaporite sequence. In the southern Rioni Basin, the oil in existing fields has either anticlinal four-way closures (Supsa) or a subthrust trap (Shromisubani) related to the leading edge of the north-vergent Achara–Trialet folded belt. Despite the long history of petroleum exploration in the Rioni Basin, these proven plays are not fully understood and systematically explored using modern technology. The existence of an Upper Jurassic regional evaporite seal highlights the possibility of pre-salt plays in the northern part of the basin.

Abstract In the 1930s, Alfred Bentz, August Moos and Karl Krejci-Graf were among the most noteworthy petroleum geologists in Germany. Being scientific modernists, they systematized the search for oil, introducing modern exploration methods. All three, at some stage, worked for the German state on providing the petroleum needed by the German military during World War II. The three colleagues seem to have had an amicable relationship. They were, however, very different. Bentz was not a member of the National Socialist party but obviously lent his expertise to the regime; as did Krejci-Graf, who, although also was not a party member, was a member of the SS, whereas Moos, due to his Jewish background, was murdered in January 1945 in the concentration camp of Buchenwald. This paper endeavours to sketch the lives of the three colleagues, highlighting their relationship and the interconnectedness of contemporary moral issues with professional and scientific demands.

Abstract 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.

Abstract Tectonic, geologic, geochemical, geochronologic, and ore deposit data from the U.S. Geological Survey-led assessment of 26 porphyry belts identified in the central Tethys region of Turkey, the Caucasus, Iran, western Pakistan, and southern Afghanistan relate porphyry mineralization to the tectonomagmatic evolution of the region and associated subduction and postsubduction processes. However, uplift, erosion, subsidence, and burial of porphyry systems, as well as post-mineral deformation, also played an essential role in shaping the observed metallogenic patterns. We present a methodology that systematically evaluates the relationship between the level of erosion, the extent of cover, and the number of known porphyry occurrences in porphyry belts. Porphyry belts that exhibit coeval volcanic-to-plutonic rock aerial ratios between 33 and 66 and limited cover contain numerous identified porphyry occurrences. These belts are relatively well explored because porphyry systems are not eroded or buried. Porphyry belts with volcanic-to-plutonic ratios that are greater than 66, but are modestly covered, contain fewer identified porphyry occurrences. Current exploration in these belts is increasingly identifying porphyry systems under associated epithermal deposits. Porphyry belts that show volcanic-to-plutonic ratios that are greater than 66, but are extensively covered, contain few identified porphyry occurrences. These belts have not been extensively explored but have potential for discoveries under cover. Deformed porphyry belts exhibit variable volcanic-to-plutonic ratios that are typically below 33, but can be as high as 60. Commonly, these deformed belts are extensively covered. Exploration efforts for porphyry deposits in these variably exhumed belts have been limited. Exploration has resulted in the identification of 62.7 million tonnes (Mt) of copper, 2.0 Mt of molybdenum, and 4.200 t of gold in the 45 porphyry deposits contained in the 26 porphyry belts of the region: (1) 54.7 Mt of copper (87% of total), 1.74 Mt of molybdenum (87%), and 3,370 t of gold (80%) occur in the 25 deposits of the four porphyry belts that exhibit coeval volcanic-to-plutonic ratios between 33 and 66 and limited cover; (2) 5.44 Mt of copper (9%), 0.148 Mt of molybdenum (7%), and 581 t of gold (14%) are contained in the 11 deposits of the 11 porphyry belts that display volcanic-to-plutonic ratios greater than 66 and modest cover; (3) 2.08 Mt of copper (3%), 0.110 Mt of molybdenum (6%), and 244 t of gold (6%) occur in the seven deposits of the three porphyry belts that have volcanic-to-plutonic ratios that are greater than 66 and extensive cover; and (4) 0.388 Mt of copper (1%), 0.006 Mt of molybdenum (<<1%), and 6 t of gold (<<1%) are contained in the two deposits of the eight deformed and covered porphyry belts with variable but typically low volcanic-to-plutonic ratios. The central Tethys region is receiving considerable exploration attention. It hosts the Kadjaran (4.6 Mt Cu), Sungun (5.1 Mt Cu), Sar Cheshmeh (8.9 Mt Cu), and Reko Diq (23.0 Mt Cu) world-class porphyry deposits. Continued exploration for porphyry deposits in the region will likely lead to new discoveries in known porphyry belts, particularly under cover and below high- and intermediate-sulfidation epithermal systems.