Structure of the Earth's crust of the Eastern Rhodopes (Southern Bulgaria) from the regional deep reflection seismic profile Ivaylovgrad–Ardino

Article in Press
Pages: 
pp. 3-30
Bulgarian Geological Society, Acad. G. Boncev Str., Bl. 24, 1113 Sofia, Bulgaria
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Boncev Str., Bl. 24, 1113 Sofia, Bulgaria
Department of Mineralogy and Petrography, University of Mining and Geology “St Ivan Rilski”, 1700 Sofia, Bulgaria
Geological Institute, Bulgarian Academy of Sciences, Acad. G. Boncev Str., Bl. 24, 1113 Sofia, Bulgaria
Abstract: 

This paper presents a geological interpretation of the deep seismic profile Ivaylovgrad–Ardino, which was published in 1996. Four plates are distinguished according to their seismic features that build up the Eastern Rhodope Terrane. They have a total thickness of 22–24 km and layered structures with sub-oceanic character. The lower two plates (1, 2) are westward obducted on the Rila-Western Rhodope Terrane, forming one obduction complex. Plate 3 is probably also a part of the obduction complex. Plate 4 is thrust southward on all plates. A Kobilino Crypto-dome, comprising Plates 1 and 2 and covered discordantly by the third one, is found at the eastern part of the profile at 7–7.5 km depth. The two lower plates do not appear on the surface, but some ultrabasic to basic bodies are supposed to be parts of them, rising as tectonic slices. The Plate 3 is revealed on the surface at the eastern part of the seismic profile (east of Avren Fault), and is built up mainly by the Pre-Rhodopean Supergroup metamorphic rocks, respectively from the seismically indistinguishable Upper and Lower Allochthon. The Plate 4 appears mainly at the western end of the profile (between Mishevsko Village and Ardino Town), and is built up by the metamorphic rocks of the Rhodopean Supergroup from the Startsevo Lithotectonic Unit (or Middle Allochthon). Five fault and shear zone systems of different ages are distinguishable in all plates. Transparent areas in the plates are interpreted as magma chambers of the Paleogene volcanoes, others as Upper Cretaceous and Paleogene (?) plutons. Because these magmatic chambers are located in the sub-oceanic crust, both intermediate and acid Paleogene volcanics have isotopic characteristics similar to those of the metasomatized mantle.

Keywords: 

Eastern Rhodope Terrane, obduction, Mohorovichich Discontinuity, crypto-dome, schizosphere-plastosphere, Paleogene volcanism

VOLUME 49 (1)/April 2020

Bulgarian Geological Society, Acad. G. Boncev Str., Bl. 24, 1113 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Boncev Str., Bl. 24, 1113 Sofia, Bulgaria
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Department of Mineralogy and Petrography, University of Mining and Geology “St Ivan Rilski”, 1700 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Boncev Str., Bl. 24, 1113 Sofia, Bulgaria

Faculty of Geology and Geography, Department of Geology, Palaeontology and Fossil Fuels, Sofia University “St Kliment Ohridski”, 15 Tsar Osvoboditel Blvd, 1513 Sofia, Bulgaria
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Geological Institute, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 24, 1113 Sofia, Bulgaria

Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, Iran
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Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, Iran
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Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, Iran
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Faculty of Science, Department of Geology, Ferdowsi University of Mashhad, Mashhad, Iran