Distinguishing climate and tectonic signals in the stratigraphy of the Kura Basin, the southeastern foreland of the Greater Caucasus

Abstract

Assessing the relative contributions of tectonics and climate in orogenic systems and the stratigraphy preserved within their fringing basins has guided research for decades. Determining the role of these contributions is non-trivial and is difficult due to variations in both magnitude and period over which fluctuations in tectonics and climate occur, typically >105 – 7 years and <105 years, respectively. The Greater Caucasus is a young orogen that offers a unique opportunity to assess these critical roles through analysis of exposures of the foreland stratigraphy. Here, we synthesize available measured stratigraphic sections from within the Kura Fold-Thrust Belt and adjoining regions, creating multiple paleogeographic reconstructions for key regional chronostratigraphic stages, and then assessing the Kura Basin’s response time throughout these stages. We use basin response time as a proxy for whether tectonics or climate fluctuations could be preserved within the Kura Fold-Thrust Belt stratigraphy and, thus, what changes in depositional environments during those periods are more likely to reflect. In general, estimates of basin response times indicate that tectonic signals could be preserved throughout the Kura Basin during the deposition of the Productive Series. Climatic signals would likely be preserved during the deposition of the Akchagyl stage, although tectonics signals cannot be ruled out. During the Apsheronian stage, both tectonic and climate signals can be preserved. These results highlight that a foreland basin system can fluctuate between being able to record mixtures of tectonic and climatic signals during both different geologic stages and within the same stage across a foreland.