Petro-geochemical features of the Bajocian island-arc volcanism in the Lesser Caucasus (Azerbaijan)


Keywords: Bajocian volcanism, island arc, REE distribution, Eu/Eu* ratio, multi-element plots, Lesser Caucasus

Abstract

This article discusses the petro-geochemical features of the Bajocian volcanism in the Azerbaijan Lesser Caucasus. Jurassic volcanism, manifested with varying intensity in the Lok-Karabakh zone, took place in various geodynamic settings, depending on the alternation of extension and compression processes in the island arc. Under these conditions, in the Lesser Caucasus during Middle Jurassic Epoch, two volcanic associations were formed: the Bajocian basalt-rhyolite and the basalt-andesite-dacite-rhyolite of the Bathonian age. It was found that the volcanic rocks of the Lower Bajocian complex belong to the tholeiitic series, and the Upper Bajocian rocks belong to the calc-alkaline series. In the rocks of the association, light REE slightly prevail over heavy ones and form almost flat spectra, the normalized plots are characterized by the chondritic nature of the distribution of rare earth elements, and the lines are parallel to the spectrum of the distribution of rare earth elements in MORB. In such rocks particularly the europium ratio (Eu / Eu * = 0.81–1.21) approaches 1 and low La / Yb ratios are observed. In some samples of more basic rocks, the content of heavy REE increases. Such a distribution of REE in the studied volcanic rocks is common for basic rocks of the tholeiitic series in typical island arcs. In the analyzed single rhyolite sample, a negative Eu anomaly is observed (Eu / Eu * = 0.56). The volcanic rocks on the primitive mantle normalized multi-element plots are characterized by depletion in Ta, Nb and enrichment in LILE (Rb, Ba, Pb, U, Th), which is characteristic of island arc-related volcanic rocks of supra-subduction zones (SSZ). The rocks are also depleted in titanium, potassium, and phosphorus. It was concluded that, in terms of geochemical features, the Middle Jurassic igneous rocks were formed at the ensimatic island arc, which was the initial stage of the development of the island arc tectonic setting, replaced in the Upper Jurassic by ensialic subduction.

Author Biographies

Nazim A. Imamverdiev
Baku State University, Azerbaijan Republic, Baku
Araz I. Orudzhov
Azerbaijan International Mining Company, Azerbaijan Republic, Baku
Anar A. Valiyev
Azerbaijan International Mining Company, Azerbaijan Republic, Baku
Samir S. Mursalov
Azerbaijan International Mining Company, Azerbaijan Republic, Baku

References

1. Abdullaev, R.N., Ismet, A.R., Bagirbekova, O.D., Abdullayev, I.A., 1979. Vozrastnoye raschleneniye magmaticheskikh obrazovaniy severo-vostochnoy chasti Malogo Kavkaza po dannym K-Ar metoda. Baku, Elm, 146 [Dismemberment of the northeastern Lesser Caucasus magmatic formations based on K-Ar method]. (In Russian).
2. Abdullaev, R.N., Mustafayev, G.V., Mustafayev, M.A., 1988. Mezozoyskiye magmaticheskiye formatsii Malogo Kavkaza i svyazannoye s nimi endogennoye orudeneniye. Baku, Elm, 157 [Mesozoic igneous formations of the Lesser Caucasus and associated endogenous mineralization.]. (In Russian).
3. Baba-zade, V. M. Musaev, Sh. D. Akhmedov, A.Z., Abdullaeva, Sh.F., 2015. Veshchestvennyy sostav mineral’nogo syr’ya Chovdarskogo zolotorudnogo mestorozhdeniya. [The material composition of the mineral commodities of the Chovdar gold deposit]. Vestnik Bakinskogo Universiteta, seriya yestestvennykh nauk, 1, 87–120 (In Russian). .
4. Balashov Yu.A., 1976. Geokhimiya redkozemel’nykh elementov. M.: Nauka, 265 [Geochemistry of Rare Earth Elements]. (In Russian).
5. Frolova, T.I., Burikova, I.A., 1997. Magmaticheskiye formaty sovremennykh geotektonicheskikh obstanovok. Izd-vo Moskovskogo universiteta, 319 [Magmatic Formations of Recent Geotectonic Settings]. (In Russian).
6. Geologiya Azerbaydzhana. T. III, Magmatizm, 2003. Baku: «Nafta-Press», 524 [Geology of Azerbaijan. Vol. III, Magmatism] (In Russian).
7. Gill, J.B., 1981. Orogenic andesites and plate tectonics. N.Y.-L. Berlin: Springer-Verlag, 396.
8. Hollocher, K., Robinson, P., Walsh, E. & Roberts, D., 2012. Geochemistry of amphibolite facies volcanics of the Støren Nappe in extensions southwest and west from the Trondheim region, western Gneiss Region, Norway: A key to correlations and paleotectonic settings. American Journal of Science 312, 357–416
9. Imamverdiyev, N.A., 2003. Geochemistry of rare-earth elements of the Late Cenozoic volcanic series of the Lesser Caucasus. Geochemistry International, «Springer» Pleiades Publishing, Ltd, vol.4, 4, 379–394.
10. Le Bas, M.J., Le Maitre, R.W., Streckeisen, A. and Zanettin, B., 1986. A chemical classification of volcanic rocks based on the total alkali-silica (TAS) diagram. J. Petrol., 27, 745–750.
11. Mustafaev, M.A., 2007. Petrologiya i geodinamicheskiye usloviya formirovaniya mezozoyskikh magmaticheskikh kompleksov kavkazskoy okrainy tetisa (Azerbaydzhan). Vestnik Bakinskogo Universiteta, seriya yestestvennykh nauk, 4, 139–152 [Petrology and geodynamic conditions for the formation of the Mesozoic magmatic complexes of the Tethys Caucasian margin (Azerbaijan)]. (In Russian).
12. Ostroumova A. S., Tsenter I. Ya., 1986. Analogi marianit- boninitovoy serii v yurskikh vulkanitakh Karabakhskogo khrebta (Maliy Kavkaz). Izvestiya AN SSSR, t. 290, 2, 441–445 [Analogs of the marianite-boninite series in the Jurassic volcanics of the Karabakh ridge (Lesser Caucasus)]. (In Russian).
13. Paffengol’ts, K.N., 1932. «Kedabek». [Gedabek]. Gosudarstvo. nauchno-tekhn. geol.-razv. izd. Leningrad- Moskva, 64 (In Russian).
14. Pearce Dzh.A., Lippard S. Dzh., Roberts S., 1987. Osobennosti sostava i tektonicheskoye znacheniye ofiolitov nad zonoy subduktsii. M.: Mir, 134–165 [Characteristics and tectonic significance of supra- subduction zone ophiolites]. Geologiya okrainnykh basseynov. (In Russian).
15. Pearce, J.A., 1982. Trace element characteristics of lavas from destructive plate boundaries. Thorpe R. S. (ed.) Andesites. Wiley, Chichester, 525–548.
16. Peccerillo, A., Taylor, S.R., 1976. Geochemistry of Eocene calc-alkaline volcanic rocks from the Kastamonu area, northern Turkey. Contrib. Miner. Petrol., vol. 58, 1, 63–81.
17. Sadykhov, E.A., 2019. Mezozoyskiye plutonicheskiye kompleksy Lok-Garabagskoy zony Malogo Kavkaza: geokhimicheskaya kharakteristika, vozrast i magmaticheskiye istochniki: Avt. diss... kand. geol. – min. nauk. Vserossiyskiy nauchno-issledova-tel’skiy geologicheskiy institut im. A. P. Karpinskogo. Sankt- Peterburg, 25 [Mesozoic plutonic complexes of the Lok-Karabagh zone of the Lesser Caucasus: geochemical characteristics, age and magmatic sources: Doctor of Philosophy thesis]. (In Russian).
18. Sun, S.S., McDonough, W.F., 1989. Chemical and isotopic systematics of oceanic basalts: implications for mantle composition and processes. Eds. A. D. Sannders, M. I. Norry. Magmatism in the ocean basin. Geol. Soc. Spec. Publ., 42, 313–345.
19. Valiyev, Anar, Bayramov, Aydin, Ibrahimov, Javid et al., 2018. Geological Setting and Ore Perspective of the New Discovered Gadir Low Sulfidation Epithermal Deposit, Gedabek NW Flank, Lesser Caucasus, Azerbaijan. Universal Journal of Geoscience, 6(3), 78–101.
20. Winchester, & Floyd, 1977. Geochemical magma type discrimination; application to altered and metamorphosed basic igneous rocks. Earth Planet. Sci. Lett. v. 28, 325– 343.
Published
2022-08-03
How to Cite
Imamverdiev, N., Orudzhov, A., Valiyev, A., & Mursalov, S. (2022). Petro-geochemical features of the Bajocian island-arc volcanism in the Lesser Caucasus (Azerbaijan). Journal of Geology, Geography and Geoecology, 31(2), 280-292. https://doi.org/https://doi.org/10.15421/112226