Active deformation and Plio-Pleistocene fluvial reorganization of the western Kura fold-thrust belt, Georgia: Implications for the evolution of the Greater Caucasus Mountains

Lasha Sukhishvili, Adam M. Forte, Giorgi Merebashvili, Joel Leonard, Kelin X. Whipple, Zurab Javakhishvili, Arjun Heimsath, Tea Godoladze

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish (US)
JournalGeological Magazine
DOIs
StateAccepted/In press - 2020

Keywords

  • Alazani basin
  • burial age dating
  • Gombori range
  • Greater Caucasus
  • Keywords:
  • Kura fold-thrust belt
  • palaeocurrent analysis
  • tectonic geomorphology

ASJC Scopus subject areas

  • Geology

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