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The Caucasus orogen lies at Europe's cross-road with Asia and Arabia, and is one of the world's outstanding Mountain belts. It consists of the northern foreland basins, the Greater Caucasus, the intramontane basins (Kura-Kartli-Rioni; ∼ 200 m elevation) and the Lesser Caucasus. North of the Greater Caucasus the deep sedimentary Terek and Kuban basin (> 6000 m; up to 1,600 m elevation) forms the transition to the Scythian platform. The Greater Caucasus is Europe's highest and youngest mountain range with Mt. Elbrus culminating at 5642m, and rock uplift of more than 8,000 m in the last 2 Myr. The intramontane basin is one of the world's earliest sites of human society with 1.8 Ma old humanoid remains of Dmanisi (Georgia). The Lesser Caucasus with lower topography (∼ 3000 m), is a zone of important volcanic and seismic activity. In the East and West, the Caucasus topography is bound by two very deep basins, the South Caspian Sea and the Black Sea, hosting one of the world's largest oil and gas provinces.
The presentation will address the tectonics of the Greater Caucasus, mainly along an a traverse far east of Dmanisi, the Eden of 1.8-2.0 My old hominids. The overall tectonic setting of the Greater Caucasus corresponds to a doubly verging mountain-belt with two external fold-and-thrust belts. It corresponds to the inverted Mesozoic Greater Caucasus Basin. The evolution of the margin shows a passive margin type geometry and is related to the back-arc rift processes resulting from the northward subduction of the oceanic domains beneath the Lesser Caucasus arc. The evolution of the margin - its successive extensional and inversion events - is related to the geodynamics of the subduction zone. The sedimentation is influenced by carbonate environment linked to the platform to the north and volcanic derived sediments coming from the south. Following a series of rifting events, a number of Jurassic to Cretaceous inversions are characteristic of the Greater Caucasus basin/margin. The basin forms the connection between the oceanic realms of the Black Sea and the South Caspian Sea. The basin entirely develops on continental crust.
Starting in early Paleogene, and accelerating in early Miocene, deformation is a strong ongoing process throughout the whole Caucasus. Located since Paleogene in the paleogeographic realm of the Eastern Paratethys, it remains unclear at which time the Caucasus emerged above sea level. A major debate concerns the existence of subduction slabs beneath the Caucasus. It is generally admitted that the Lesser Caucasus is situated above an old slab. An incipient subduction is believed to occur at the northern edge of the Black Sea and in the central Caspian Sea (Absheron Ridge), the western and eastern extensions of the southern front of the Greater Caucasus. The Moho plunges from about 40 km beneath the Kura basin to more than 60 km beneath the Greater Caucasus and rises to 40 km again under the northern foreland basin.
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