Late Triassic age of moshevani suite of the Loki massif (Georgia, the Caucasus)
The Loki massif is located near the southern border of Georgia and is represented by large anticline structure of E-W oriented extension. The most ancient formations of the massif are crystalline schists outcropping along western, northern and southern peripheries of the massif. Crystalline schists are penetrated by granites and divided in two age complexes, Paleozoic and Middle Jurassic. Almost around all perimeter crystalline basement and granites are transgressively overlaid by series of strata of conglomerates and quartz sandstones, desribed as Moshevani suite and its age has so far been given as Hettangian. A section located at the western periphery of the Loki massif, to the N-E of v. Gora, in the gorge of the r. Gorastskali, right tributary of r. Moshevani, was studied in these sediments. Slides were prepared from the selected samples using decantation method (separation of fraction 3―30 µm). The samples were placed into a 45 mm water column, where the heavy fraction was allowed to settle for 3 minutes, while the fine-fraction was saved for slide preparation after 45 minutes. All slides were studied with a Carl Zeiss microscope «Amplival» at 1200x magnification. Despite the lacking of nannofossils in these deposits, a complex association of calcareous nannofossils including Crucirhabdus minutes Jafar 1983; C. primulus Rood, Hay & Barnard 1973; Prinsiosphaera triassica Jafar 1983; Tetralithus cassianus Jafar 1983; T. pseudotrifidus Jafar 1983; Hayococcus floralis Jafar 1983; known from Norian-Rhaetian stage. Due to this complex the presence of Upper Triassic deposits has been found for the first time within the limits of Loki-Karabakhian structural facial zone. Therefore, taking into consideration the above mentioned data a new corrected lithostratigraphic column and a map of the area were composed.
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Adamia, Sh. A., Djavakhishvili, Sh. I., & Zesashvili, V. I. (1960). Geological map 1: 50000. Sheets: K-38-101-B, K-38-102-A. Consolidated Geological Report of the Mashavera Exploration and Survey Party and the Geological Expedition of South-Eastern Georgia according to the works of 1956―1959. Tbilisi: Funds of the Georgian Geological Survey (in Russian).
Baranova, Z. E., Kirichkova, A. I., & Sauer, V. V. (1975). Stratigraphy and flora of Jurassic sediments in the Eastern Caspian Depression. Leningrad: Nedra (in Russian).
Barkanov, I. V. (1935). Essay on Geology and Ore fields of the Northern Part of the Stepanavan District of the Armenian SSR and the Bashkichet District of the Georgian SSR. Tbilisi: Funds of the Georgian Geological Survey (in Russian).
Barskov, I. S., Yanin, B. T., & Kuznetsova, T. V. (2004). Paleontological Descriptions and Nomenclature. Moscow: Moscow University Press (in Russian).
Vashakidze, G. T. (1999). Petrology and isotopic geochronology of the Loki massif: Extended abstract of candidate's thesis. Tbilisi (in Georgian).
Gabuniya, K. E. (1927). Chatakhi iron-ore district. Tbilisi: Funds of the Georgian Geological Survey (in Russian).
Gabuniya, K. E., & Gamkrelidze, P. D. (1942). Geology of the southern part of Borchalo region. Proceedings of the Geological Institute of the Academy of Sciences of the Georgian SSR. Geological series, VI(1), 5―72 (in Russian).
Gamkrelidze, I. P. (2000). Once more on the tectonic zoning zoning of the territory of Georgia. Proceedings of the Geological Institute of the Academy of Sciences of Georgia. New series, (115), 204―208 (in Russian).
Gamkrelidze, I. P., Dudauri, O. Z., Nadareishvili, G. Sh., Skhirtladze, N. I., Tutberidze, B. D., & Shengelia, D. M. (2002). Geodynamic typification of the Precambrian-Phanerozoic magmatism of Georgia. Proceedings of the Geological Institute of the Academy of Sciences of Georgia. New series, (117), 105―126 (in Russian).
Gamkrelidze, P. D. (1949). Geological structure of the Adjara-Trialeti folded system. Tbilisi: Publishing House of the Geology and Mineralogy Institute of the Academy of Sciences of the Georgian SSR. Monographs, №2 (in Russian).
Gamkrelidze, P. D., & Edilashvili, V. Ya. (1940). Geological description of the K-38-XXI sheet (Tbilisi). Tbilisi: Funds of the Georgian Geological Survey (in Russian).
Grushevoy, V. G. (1935). Geological essay of the North-Western part of the Alaverdi District of the Armenian SSR and part of the Borchalo District of the Georgian SSR. Tbilisi: Funds of the Georgian Geological Survey (in Russian).
Delle, G. V. (1967). Middle Jurassic flora of the Tkvarcheli coal basin. Proceedings of the Botanical Institute of the Academy of Sciences of the USSR. Ser. Paleobotany, (6), 52―132 (in Russian).
Djavakhishvili, Sh. I. (1958). Petrography and the geological structure of the eastern part of the Loki massif. Proceedings of the Geological Institute of the Academy of Sciences of the Georgian SSR. Series of mineralogy and petrography, IV, 201―359 (in Russian).
Djanelidze, A. I. (1946). On the Question of the Loki Liassic. Bulletin of the Academy of Sciences of the Georgian SSR, VII(6), 361―363 (in Russian).
Zaridze, G. M. (1961). Petrography of magmatic and metamorphic rocks of Georgia. Moscow: Gosgeoltekhizdat (in Russian).
Zaridze, G. M., & Tatrishvili, N. F. (1945). By the age of the granitoids of the gorge of the r. Dumblud. Bulletin of the Academy of Sciences of the Georgian SSR, 6(10), 803―805 (in Russian).
Zesashvili, V. I. (1955). Geology of a part of the r. Poladauri basin. Proceedings of the Geological Institute of the Academy of Sciences of the Georgian SSR. Geological series, IX(1), 47―189 (in Russian).
Zesashvili, V. I. (1967). To the stratigraphy of the Lower Jurassic sediments of South-Eastern Georgia. Proceedings of the Geological Institute of the Academy of Sciences of the Georgian SSR. New series, (15), 5―25 (in Russian).
Zesashvili, V. I., & Chikhradze, G. A. (1965). Jurassic system. In Geological structure and metallogeny of South-Eastern Georgia (pp. 34―54). Tbilisi: Mecniereba (in Russian).
Kitovani, Sh. K. (1955). On the oil-bearing capacity of the Mesozoic deposits of the Loki and Krami massif areas (geological report of the Krami geological party on works in 1954). Tbilisi: Funds of the Georgian Geological Survey (in Russian).
Koiava, K. P. (2000). Biostratigraphy of the Liassic-Aalenian sediments of the Loki massif based on ammonites and calcareous nannoplankton. Master's dissertation. Funds GTU (in Georgian).
Komar, V. A., & Vysotsky, V. P. (1946). Report on the subject «Geological and structural studies in the Bashkichet and Borchalo districts of the Georgian SSR». Tbilisi: Funds of the Georgian Geological Survey (in Russian).
Nutsubidze, K. Sh. (1966). The Lower Jurassic Fauna of the Caucasus. Proceedings of the Geological Institute of the Academy of Sciences of the Georgian SSR. New series (is. 8). Tbilisi: Metsniereba (in Russian).
Panov, D. I. (1978). Regional-stratigraphic division of the Lower Jurassic and Aalenian deposits of the Lesser Caucasus. In Problems of stratigraphy and historical geology (pp. 153―164). Moscow: Moscow State University Publishing House (in Russian).
Svanidze, Ts. I. (1971a). On the age of the flora-bearing deposits of the lower Jurassic of the Dzirul and Loki crystalline massifs. Works of Tbilisi State University. Ser. A. Physical, Mathematical and Natural Sciences, (2), 165―169.
Svanidze, Ts. I. (1971b). Jurassic flora of Georgia: Doctor’s thesis. Tbilisi (in Russian).
Svanidze, Ts. I. (1996). The Early Jurassic flora of Georgia and its position in the same age floras of Eurasia. Tbilisi: Publication of Tbilisi State University (in Russian).
Topchishvili, M. V. (1989). Biostratigraphic differentiation of the Lower Jurassic-Aalenian deposits of Loki salient by ammonites. Bulletin of the Academy of Sciences of the Georgian SSR, 136(2), 369―372 (in Russian).
Topchishvili, M. V. (1996). Stratigraphy of the Lower Jurassic and Aalenian deposits of Georgia. Proceeding of the Geological Institute of the Georgian Academy of Sciences. New series, (is. 108). Tbilisi: Nike (in Russian).
Topchishvili, M. V., Lominadze, T. A., Tsereteli, I. D., Todria, V. A., & Nadareishvili, G. Sh. (2006). Stratigraphy of the Jurassic Deposits of Georgia. Proceedings of the A. Janelidze Geological Institute. New Series (is. 122) (in Russian).
Turutanova-Ketova, A. I. (1939). Records on stratigraphy and Age of the Mangystau Coal Deposit in the Kazakh SSR. Scientific notes of the Leningrad State University, 34(7), 285―317 (in Russian).
Adamia, S., Zakariadze, G., Chkhotua, T., Sad¬rad¬ze, N., Tsereteli, N., Chabukiani, A., & Gvent¬sadze, A. (2011). Geology of the Caucasus: a review. Turkish Journal of Earth Sciences, 20, 489—544. doi:10.3906/yer-1005-11.
Bown, P. R. (1992). Late Triassic-Early Calcareous nannofossils of the Queen Charlotte Islands, British Columbia. Journal of Micropalaeontology, 11, 177—188. https://doi.org/10.1144/jm.11.2.177.
Bown, P. R. (1987). Taxonomy, biostratigraphy, and evolution of Late Triassic-Early Jurassic calcareous nannofossils. Special Papers in Paleontology, 38, 1—118.
Bown, P. R., & Lord, A. R. (1990). The occurrence of calcareous nannofossils in the Triassic/Jurassic boundary interval. Rapport du Working group «Limite Trias-Jurassique», Lyon 1988. Les Cahiers de l’Universiteґ catholique de Lyon, Seґrie Sciences, 3, 127—136.
Bralower, T. J., Bown, P. R., & Siesser, W. G. (1991). Significance of Upper Triassic nannofossils from the Southern Hemisphere (ODP Leg 122, Wombat Plateau, N.W. Australia). Marine Micropaleontology, 17(1-2), 119—154. https://doi.org/10.1016/0377-8398(91)90025-2.
Bralower, T. J., Bown, P. R., & Siesser, W. G. (1992). Upper Triassic Calcareous nannoplankton bio-stratigraphy, Wombat Plateau, northwest Australia. In U. Rad, B. U. Haq, R. B. Kidd, & S. O’Connell (Eds.), Proceedings of the Ocean Drilling Program, Scientific Results (Vol. 122, pp. 437—451).
Brenner, W., Bown, P. R., Bralower, T. J., Crasquin-Soleau, S., Deґpe`che, F., Dumont, T., Zaninetti, L. (1992). Correlation of Carnian to Rhaetian Palynological, Foraminiferal, Calcareous nannofossil, and ostracode biostratigraphy, Wombat Plateau. In U. Rad, B. U. Haq, R. B. Kidd, & S. O’Connell (Eds.), Proceedings of the Ocean Drilling Program, Scientific Results (Vol. 122, pp. 487—495).
De Capoa, P., & Radoičić, R. (1991). Calcareous Nannofossils in Middle Triassic (Anisian) — a preliminary note. Geologija, 34(3), 77—79.
Dobruskina, I. (1994). Triassic floras of Eurasia. Sprin¬ger.
Gardin, S., Krystyn, L., Richoz, S., Bartolini, A., & Galbrun, B. (2012). Where and when the earliest coccolithophores? Lethaia, 45(4), 507—523. https://doi.org/10.1111/j.1502-3931.2012. 00311.x.
Halle, T. G. (1908). Zur Kenntnis der mesozoischen Equisetales Schwedens. Kungliga Svenska Vetenskapsakademiens Handlingar, 43(1), 1—40.
Jafar, S. A. (1983). Significance of Late Triassic calcareous nannoplankton from Austria and southern Germany. Neues Jahrbuch fьr Geologie und Palдeontologie, 166, 218—259.
Janofske, D. (1992). Kalkiges Nannoplankton, insbesondere kalkige Dinoflagellaten-Zysten der alpinen Ober-Trias: Taxonomie, Biostratigraphie und Bedeutung fьr die Phylogenie der Peridiniales. Berliner Geowissenschaftliche Abhandlungen, 4, 1—53.
Koiava, K., Gavtadze, T., Glonti, V. B., & Kvaliashvili, L. (2013). First Record on Lower Jurassic-Aalenian Calcareous Nannofossils of Georgia: The 5th International Scientific Conference of Young Scientists and Students «Fundamental and Applied Geological Science: Achievements, Prospects, Problems and Ways of Their Solutions» (pp. 171―172). Baku.
Koiava, K., Mosar, J., Gavtadze, T., Kvaliashvili, L., & Mauvilly, J. (2015). Late Triassic Calcareous Nannoplankton from Georgia and New Age of Moshevani Suite (Caucasus): The 13th Swiss Geoscience Meeting (pp. 185―186). Basel.
Posch, F., & Stradner, H. (1987). Report on Triassic nannoliths from Austria. Abhandlungen der Geologischen Bundesanstalt, 39, 231—237.
Rai, J., Upadhyay, R., & Sinha, A. K. (2004). First Late Triassic nannofossil record from the Neo-Tethyan sediments of the Indus-Tsangpo Suture Zone, Ladakh Himalaya, India. Current Science, 86, 774―777.
Schweitzer, H. J., Van-Konijnenburg-Van Cittert, J. H. A., & Van Der Burgh, J. (1997). The Raetho-Jurassic flora of Iran and Afghanistan: 10. Bryophyta, Lycophyta, Sphenophyta, Pterophyta-Eusporangiatae and Protoleptosporangiata. Palaeontographica, 243B, 103—192.
Vaez-Javadi, F. (2011). Middle Jurassic flora from the Dansirit Formation of the Shemshak Group, Alborz, north Iran. Alcheringa, 35(1), 77―102. https://doi.org/10.1080/03115518.2010.489424.
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