Post-Collisional Shift from Polygenetic to Monogenetic Volcanism Revealed by New 40Ar/39Ar Ages in the Southern Lesser Caucasus (Armenia)
Journal of Volcanology and Geothermal Research 412 (2021) 107192 Contents lists available at ScienceDirect Journal of Volcanology and Geothermal Research journal homepage: www.elsevier.com/locate/jvolgeores Post-collisional shift from polygenetic to monogenetic volcanism revealed by new 40Ar/39Ar ages in the southern Lesser Caucasus (Armenia) Patrick Sugden a, Khachatur Meliksetian b, Ivan P. Savov a,⁎, Dan Barfod c, Marjorie Wilson a, Charles Connor d, Gevorg Navasardyan b, Edmond Grigoryan b, David Manucharyan b,d a Institute of Geophysics and Tectonics, School of Earth and Environment, University of Leeds, Leeds LS2 9JT, UK b Institute of Geological Sciences, National Academy of Sciences of Armenia, 24a Marshal Baghramian Avenue, Yerevan 0019, Armenia c NEIF Argon laboratory, Scottish Universities Environmental Research Centre, Rankine Avenue, Scottish Enterprise Technology Park, East Kilbride, G75 0QF, Scotland, UK d School of Geoscience, University of South Florida, 4202 E. Fowler Avenue, NES 107, Tampa, FL 33620-555, USA article info abstract Article history: The post-collisional Syunik and Vardenis volcanic highlands, located in the southern Lesser Caucasus mountains Received 13 September 2020 (part of the Arabia-Eurasia collision zone) are host to over 200 monogenetic volcanoes, as well as 2 large Quater- Received in revised form 18 January 2021 nary polygenetic volcanoes in the Syunik highland. The latter are overlain by lavas from the monogenetic volca- Accepted 25 January 2021 noes, suggesting there was a transition in the style of volcanic activity from large-volume central vent eruptions Available online 31 January 2021 to dispersed small-volume eruptions. 12 new high quality 40Ar/39Ar ages are presented here, with 11 ages calcu- lated by step-heating experiments on groundmass separates, and the final age obtained from total fusions of a Keywords: 40Ar/39Ar dating population of sanidines.
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