Plutonic Magmatism of the Greater Caucasus Svaneti Segment: Zircon U-Pb Geochronology, Petrochemistry and Geodynamic Setting

Gamkrelidze, Iralki და Okrostsvaridze, Avtandil და Lee, Yuan-Hs და Tormey, Daniel და Giorgi Boichenko, Giorgi და Skhirtladze, Irakli და Gogoladze, Salome (2023) Plutonic Magmatism of the Greater Caucasus Svaneti Segment: Zircon U-Pb Geochronology, Petrochemistry and Geodynamic Setting. BULLETIN OF THE GEORGIAN NATIONAL ACADEMY OF SCIENCES, vol. 17, no. 1, 2023.

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რეზიუმე

The Greater Caucasian fold-and-thrust belt is part of the Alpine-Himalayan collisional orogenic belt. It experienced complex polycyclic development during the Late Precambrian and throughout the Phanerozoic. This article discusses new U-Pb LA-ICP-MS U-Pb geochronology and petrochemistry data on zircons from the plutons of the Svaneti segment (Georgia) of this orogen. U-Pb geochro�nological data indicate three main stages of plutonic magmatic activity: 1- Ordovician, 2- Upper Carboniferous, and 3- Middle Jurassic (Aalenian-Bajocian). At the first stage, Ordovician biotite orthogneisses (~488-475 Ma) were formed during the Caledonian orogeny in supra-subduction conditions. At the second stage, the Upper Carboniferous granodiorite–granite plutons (~320–310 Ma) were formed during the Late Variscan Orogeny also in supra-subduction conditions, while Middle Jurassic plutons were formed in post-accretional ones. At the end of the Late Triassic, during the Early Cimmerian (Indosinian) orogeny, the oceanic basin of the southern slope of the Greater Caucasus was closed. Later, at the beginning of the Jurassic, the process of stretching of the Earth's crust began, during which in the Middle Jurassic (in the Aalenian-Bajocian) stage predominantly the monzosyenitic of pluton formation took place (the third stage). The age of these plutons gradually decreases from the north to the south (~177, ~168, ~164 Ma). This indicates the spread of the process of crustal stretching from north to south. The formation of the plutons of the Main Range zone of the Greater Caucasus (island arc) took place in supra-subduction conditions of the active margin of the back-arc small oceanic basin of its southern slope, while the monzodiorites, monzosyenite and monzinite plutons, located in the Paleozoic-Triassic Dizi series and Lower Jurassic black shales, were formed on the passive margin of this basin, in conditions of continental slope and foot, which have a thin sub-oceanic Earth’s crust. © 2023 Bull. Georg. Natl. Acad. Sci.

ობიექტის ტიპი:	სტატია
თემატიკა:	Q Science > QE Geology
განმათავსებელი მომხმარებელი:	ავთანდილ ოქროსცვარიძე
განთავსების თარიღი:	17 მაისი 2023 09:20
ბოლო ცვლილება:	17 მაისი 2023 09:20
URI:	http://eprints.iliauni.edu.ge/id/eprint/11822

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