Geological evolution of South Transdanubia (Hungary) in Paleozoic time

Szederkényi Tibor: Geological evolution of South Transdanubia (Hungary) in Paleozoic time. In: Acta mineralogica-petrographica, (23) 1. pp. 3-14. (1977)

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Accepting the opinion about Precambrian age of crystalline basement of South Transdanubia declared by B. JANTSKY [1974], the oldest Paleozoic formations of South Transdanubia can be placed into Ordovician-Silurian period [K. BALOGH, 1974]. Three Ordovician-Silurian rock types are recorded: 1. Strongly folded dark grey siliceous shales with basic tuffs and agglomerates covered by Lower Triassic red sandstones. This rock sequence is interrupted by Carboniferous (?) syenite-porphyric subvolcanic body with uncertain aureole. The unexplored underlying rocks are assumed to pertain to the Precambrian granite mass. 2. The second formation represents a single depositional cycle ranging from coarse grained deposits to limestone with products of ultrabasic and basic volcanism. It forms the oldest Paleozoic part of the so called "Mecsekalja Tectonic Belt" passed along they southern margin of the Mecsek Mountains. These rocks had been superincumbent in Pre-Carboniferous upon the Precambrian "Mórágy Granite Formation" and "Górcsóny Metamorphic Formation". At the beginning of the Variscan Orogeny they had wedged into the underlying Precambrian rocks by a considerable transcurrent faulting, and they suffered a tectonic metamorphism with a slight selective melting. After Pre-Upper Carboniferous denudation of these rocks have taken place the present geological setting. 3. The third formation is formed by ultramafic lava-filled conduits surrounded with Precambrian metamorphites and granites covered by Upper Pannonian and Permian deposits. Rock-material of these vents consists mostly of clinopyroxenites, serpentinites and associated derivatives. The area affected by powerful movements from the end of the Silurian up to Upper Carboniferous. During this period had been the first manifestation of the Variscan Orogeny caused the wedging of the. above mentioned second formation into the "Mecsekalja Tectonic Belt" by transcurrent faulting. It can be placed into Earliest Carboniferous (Bretonian Phase). During Sudetic Phase a weak granitization had taken place produced microgranite intrusions, aplit veins, K metasomatism as-well as presumed syenite-porphyrite near Szalatnak. At the beginning of Upper Carboniferous the western part of the area formed a basin filled by continental Upper Carboniferous and Permian deposits. The Upper Carboniferous sequence measures more than 1000 m thickness near Téseny—Bogádmindszent covered by Upper Pannonian sediments. It contains some coal beds and coaly siltstone streaks with well determinable flora resembling to the Ruhrland one. The Upper Carboniferous coal bearing sequence changes gradually into Permian variegated sandstones, siltstones and conglomerates of about 2500 m thickness. The Permian sedimentation was interrupted by an uplift (presumably with local importance) accompanied by a quartzporphyric lava flow attributed to Saalic Phase in Western Mecsek, and by another one in Villány Mts. ranging over the Upper Permian alternating with sandstones. According to recent views the Upper Carboniferous — Permian sedimentation did not extend more than to so called "Villány—Szalatnak Deep Fracture Zone" in the Eastern direction and line of Drava river in Southern side. The basin of Upper Carboniferous and Permian are made of continental sediments (mainly fluviatile and fewer lacustrine) having a NW—SE general trend. At the end of Permian sedimentation a general sinking had taken place which produced a characteristic purplish-red basis conglomerate and sandstone mass due to Pfalz Phase. It is considered as a starting part of the mesozoic sedimentation all over Hungary. It is important to notice that if the theory of Precambrian age of Görcsöny Metamorphic —, and Mórágy Granite Formations rules out, it will result certain transformation of history of South Transdanubian Old Paleozoic series.

Item Type: Article
Journal or Publication Title: Acta mineralogica-petrographica
Date: 1977
Volume: 23
Number: 1
ISSN: 0365-8066
Page Range: pp. 3-14
Language: English
Publisher: University of Szeged, Department of Mineralogy, Geochemistry and Petrology
Place of Publication: Szeged
Related URLs:
Uncontrolled Keywords: Kőzettan, Ásványtan, Földtan
Additional Information: Bibliogr.: p. 13-14. ; ill. ; összefoglalás angol nyelven
Subjects: 01. Natural sciences
01. Natural sciences > 01.05. Earth and related environmental sciences
Date Deposited: 2016. Oct. 17. 09:25
Last Modified: 2022. Jul. 25. 10:27

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