Zircons U-Pb geochronology of the ore-bearing plutons of adjara-trialeti folded zone, lesser Caucasus and analysis of the magmatic processes
Journal
Bulletin of the Georgian National Academy of Sciences
Journal Volume
12
Journal Issue
2
Pages
90-99
Date Issued
2018
Author(s)
Abstract
Zircons of the major ore-bearing plutons (Merisi, Namonastrali, Vakijvari, Zoti, Okros-Ghele and Rkviana) of the Adjara-Trialeti Paleogene folded zone of the Lesser Caucasus were dated by the U-Pb method using the Laser Ablation ICP-MS tool at the isotope laboratory of the Department of Earth Sciences at the National Taiwan University. The results are almost identical and are as follows: Merisi (diorite), sm. #12Ge-03=43.42¡Ó0.61 Ma; Merisi (syenite) sm.#12Ge-04=42.78¡Ó0.65 Ma; Namonastrali (diorite) sm. #12Ge-05=42.42¡Ó0.5 Ma; Namonastrevi (diorite) sm.#12Ge-06=42.03¡Ó0.83 Ma; Vakijvari (syenite) sm.#12Ge-13=43.26¡Ó0.74 Ma; Zoti (syenite) sm. #12Ge-15 =43.86¡Ó0.43 Ma; Zoti (gabbro) sm.#12Ge-16=46.77¡Ó0.81 Ma; Okros-Ghele (syenite) sm. #12Ge=19-44.34¡Ó0.55 Ma; Rkviana (gabbro) sm. #12Ge-21=44.85¡Ó0.59 Ma. Based on the analysis of the results, it is obvious that the ore bearing plutons of the Adjara-Trialeti zone were intruded through the volcanic-sedimentary rocks within a short time interval, between 46-42 Ma. It should be noted that according to paleontological data, the peak of volcanic activity in the Ajara-Trialeti folded zone was similarly dated as the Middle Eocene. If we rely on these data and accept the results of the plutons zircons dating by U-Pb method above, we should assume that the volcanic activities in the region were shortly followed by plutonic injections. Proceeding from the above and the petrological-geochemical analysis of the rocks, we assert, that volcanic and plutonic formations of the Adjara-Trialeti zone are the products of the same magmatic source activity and their formation was not significantly separated in time. ? 2018 Bull. Georg. Natl. Acad. Sci.
Subjects
Adjara-Trialeti folded zone
Plutons
U-Pb geochronology
Zircon
Type
journal article