Jurassic to Cenozoic Magmatic and Geodynamic Evolution of the Eastern Pontides and Caucasus Belts, and Their Relationship With the Eastern Black Sea Basin Opening

The magmatic arcs of the Eastern Pontides and Lesser Caucasus lie in continuation from one another. A comparison of the subduction-related magmatic rocks outcropping throughout this segment of the Northern Tethyan belt exhibits chronological disparities, questioning the common subduction history of the Eastern Pontides and the Lesser Caucasus regions. New data and observations including geochronological and geochemical data, relative to subduction- to collision-related magmatic rocks, argue a novel paleogeographic reconstruction illustrating Mesozoic and Cenozoic evolution of this region. Jurassic to Early Cretaceous arc magmatism runs mainly from the Sochi-Ritsa/Bechasyn regions (Greater Caucasus) toward the southeast to the Alaverdi region and further into the Lesser Caucasus. Late Cretaceous and Cenozoic arc magmatism is evidenced throughout the Eastern Pontides extending through the Bolnisi region to the Lesser Caucasus arc. East to west, Jurassic to Early Cretaceous and Late Cretaceous to Cenozoic portions of arc split to the north and south of the Eastern Black Sea, respectively. Throughout Cretaceous subduction, this segment of the magmatic arc of the Southern Eurasian margin was torn in two due to the oblique opening of the Eastern Black Sea as a back-arc to intra-arc basin, from west to east. This reconstitution implies that the Jurassic-Early Cretaceous subduction-related magmatic rocks of the Greater Caucasus are remnant portions of the Eastern Pontides and Lesser Caucasus arcs. This infers the emplacement of subduction- to collision-related magmatic rocks throughout the Mesozoic and Cenozoic along the entire Southern Eurasian margin is solely due to a single long-lasting north dipping subduction.