Geochemistry and U-Pb Geochronology of Late Paleozoic Magmatism in a Part of the Western Balkan Zone, NW Bulgaria
Source abstract
Abstract
The Rzhanski granitoid pluton and Ignatitsa diorite porphyry bodies are considered Late Paleozoic in age, belonging to the Western Balkan Zone (WBZ) in Northwestern Bulgaria. Here, we provide U-Pb zircon geochronology of these magmatic bodies, together with their geochemistry complemented by the geochemistry of the overlying volcanic rocks. Geochemical data indicate that the intermediate to acid magmatic rocks are mostly peraluminous, calc-alkaline diorite/andesite to granite, that have an origin in a continental magmatic arc tectonic environment. All plutonic, subvolcanic and volcanic rocks exhibit uniform LILE- and LREE-enriched characteristics of an arc-related igneous suite. Zircons in the Ignatitsa diorite porphyry yield a magmatic crystallization age of 315 Ma, while the zircons in the Rzhanski aplitic metagranite pluton crystallize at 294 Ma. The record of the Variscan intrusive magmatism encompasses a region-wide, well-defined time interval 332–294 Ma in the WBZ, which coincides with those of the Central Balkan Zone and the adjacent Sredna Gora Zone. The age of the Variscan greenschist facies metamorphism using the metagranite and host greenschists relationships is limited between 294 Ma and the unpublished depositional age of 268 Ma for the overlying clastic formation in the studied part of the WBZ.
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Research context
OpenAlex topics: Geological and Geochemical Analysis · Mineralogy and Gemology Studies · Geochemistry and Elemental Analysis
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Affiliations
Department of Geology, Paleontology and Fossil Fuels, Sofia University St. Kliment Ohridski, 15 Tzar Osvoboditel Bd., 1504 Sofia, Bulgaria
Bulgarian Academy of Sciences, 1 November 15 Str., 1040 Sofia, Bulgaria
Department of Geochemistry and Petrology, Geological Institute of the Bulgarian Academy of Sciences, 24 Acad. G. Boncev Str., 1113 Sofia, Bulgaria
Department of Mineralogy, Petrology and Economic Geology, Sofia University St. Kliment Ohridski, 15 Tzar Osvoboditel Bd., 1504 Sofia, Bulgaria
Funding
Bulgarian Science Fund
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