Active deformation and Plio-Pleistocene fluvial reorganization of the western Kura fold–thrust belt, Georgia: implications for the evolution of the Greater Caucasus Mountains
- 13 August 2020
- journal article
- research article
- Published by Cambridge University Press (CUP) in Geological Magazine
- Vol. 158 (4), 583-597
- https://doi.org/10.1017/s0016756820000709
Abstract
Since Plio-Pleistocene time, southward migration of shortening in the eastern part of the Greater Caucasus into the Kura foreland basin has progressively formed the Kura fold–thrust belt and Alazani piggyback basin, which separates the Kura fold–thrust belt from the Greater Caucasus. Previous work argued for an eastward propagation of the Kura fold–thrust belt, but this hypothesis was based on coarse geological maps and speculative ages for units within the Kura fold–thrust belt. Here we investigate the initiation of deformation within the Gombori range in the western Kura fold–thrust belt and evaluate this eastward propagation hypothesis. Sediments exposed in the Gombori range have a Greater Caucasus source, despite the modern drainage network in the NE Gombori range, which is dominated by NE-flowing rivers. Palaeocurrent analyses of the oldest and youngest syntectonic units indicate a switch happened between ~2.7 Ma and 1 Ma from dominantly SW-directed flow to palaeocurrents more similar to the modern drainage network. A single successful 26Al–10Be burial date indicates the youngest syntectonic sediments are 1.0 ± 1.0 Ma, which, while not a precise age, is consistent with original mapping suggesting these sediments are of Akchagylian–Apsheronian (2.7–0.88 Ma) age. These results, along with recent updated dating of thrust initiation in the eastern Kura fold–thrust belt, suggest that deformation within the Kura fold–thrust belt initiated synchronously or nearly synchronously along-strike. We additionally use topographic analyses to show that the Gombori range continues to be a zone of active deformation.Keywords
This publication has 68 references indexed in Scilit:
- Rapid Pliocene exhumation of the central Greater Caucasus constrained by low‐temperature thermochronometryTectonics, 2011
- Cenozoic-Recent tectonics and uplift in the Greater Caucasus: a perspective from AzerbaijanGeological Society, London, Special Publications, 2010
- Evolution of the Late Cenozoic basins of Georgia (SW Caucasus): a reviewGeological Society, London, Special Publications, 2010
- Topography, relief, and TRMM‐derived rainfall variations along the HimalayaGeophysical Research Letters, 2006
- A review of burial dating methods using 26Al and 10BePublished by Geological Society of America ,2006
- Thrust-fault growth and segment linkage in the active Ostler fault zone, New ZealandJournal of Structural Geology, 2005
- Distribution of active rock uplift along the eastern margin of the Tibetan Plateau: Inferences from bedrock channel longitudinal profilesJournal of Geophysical Research, 2003
- Growth and lateral propagation of fault‐related folds in the Siwaliks of western Nepal: Rates, mechanisms, and geomorphic signatureJournal of Geophysical Research, 2002
- River incision or diversion in response to bedrock upliftGeology, 2000
- Long river profiles, tectonism, and eustasy: A guide to interpreting fluvial terracesJournal of Geophysical Research, 1994