TY - JOUR
T1 - Active deformation and Plio-Pleistocene fluvial reorganization of the western Kura fold-thrust belt, Georgia
T2 - Implications for the evolution of the Greater Caucasus Mountains
AU - Sukhishvili, Lasha
AU - Forte, Adam M.
AU - Merebashvili, Giorgi
AU - Leonard, Joel
AU - Whipple, Kelin X.
AU - Javakhishvili, Zurab
AU - Heimsath, Arjun
AU - Godoladze, Tea
N1 - Funding Information:
This research [#PhDF2016_208 and #IG 29/1/16] has been supported by the Shota Rustaveli National Science Foundation of Georgia (SRNSFG); Louisiana State University; United States National Science Foundation grant EAR-1450970 to Adam M. Forte and Kelin X. Whipple; and the Institute of Earth Sciences and National Seismic Monitoring Centre, Ilia State University. We also thank Andrea Stevens Goddard and an anonymous reviewer for comments which improved this manuscript.
Publisher Copyright:
© The Author(s), 2020
PY - 2021/4
Y1 - 2021/4
N2 - 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.
AB - 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.
KW - Alazani basin
KW - Gombori range
KW - Greater Caucasus
KW - Kura fold-thrust belt
KW - burial age dating
KW - palaeocurrent analysis
KW - tectonic geomorphology
UR - http://www.scopus.com/inward/record.url?scp=85095122798&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85095122798&partnerID=8YFLogxK
U2 - 10.1017/S0016756820000709
DO - 10.1017/S0016756820000709
M3 - Article
AN - SCOPUS:85095122798
SN - 0016-7568
VL - 158
SP - 583
EP - 597
JO - Geological Magazine
JF - Geological Magazine
IS - 4
ER -