Structure and Regional Tectonics of the Achara-Trialet Fold Belt and the Adjacent Rioni and Kartli Foreland Basins, Republic of Georgia
Chris J. Banks, Andrew G. Robinson, Math P. Williams, 1997. "Structure and Regional Tectonics of the Achara-Trialet Fold Belt and the Adjacent Rioni and Kartli Foreland Basins, Republic of Georgia", Regional and Petroleum Geology of the Black Sea and Surrounding Region, A. G. Robinson
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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.
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Regional and Petroleum Geology of the Black Sea and Surrounding Region
In 1967 and 1969, two oceanographic cruises were made in the Black Sea under the guidance of the Woods Hole Oceanographic Institute: The cruises included scientists from many countries and disciplines. Their aims were to determine the recent geological and geochemical evolution of the Black Sea, to map the shallow structure of the basin, and to study the interaction between the oxidized surface waters and the anoxic waters beneath them. The results were published 23 years ago, as AAPG Memoir 20 (Ross and Degens, 1974). During the 1969 cruise, the vessel Atlantis II collected 40 piston cores, which formed the basis of most of the subsequent geological studies that were restricted to very recent sedimentation. Speculations concerning the origin of the basin and the relationship of the geology offshore to that exposed around the margins of the Black Sea were rooted in pre-plate tectonic concepts of basin formation and were in any case hampered by a lack of relevant data (Brinkmann, 1974).
In 1976, the Glomar Challenger visited the Black Sea on Leg 42B of the Deep Sea Drilling Project and drilled and cored three deep-water sites (379, 380, and 381). Well 381 north of the Bosporus encountered sediments as old as Miocene, including some apparently deposited in shallow water (Ross, 1978).
The next major volume in Western literature to deal with the Black Sea was published a decade later, collecting papers presented two years earlier at a conference in Yalta. In this volume, a number of seismic reflection lines