Skorupa oceaniczna i ofiolity w Sudetach Środkowych w świetle rozważań tektonicznych

Zbigniew Cymerman


Oceanic crust and ophiolites in the Central Sudetes in the light of tectonic considerations.
A b s t r a c t. Znosko (1981a, b) first stated the important fact that the Sowie Góry “nappe” was lying on the rocks of the Middle Sudetic Ophiolite Complex. In the light of current geophysical and tectonic data, it still remains up-to-date. Both those articles have initiated a new look at the Paleozoic tectonic evolution of the Sudetes and its surroundings. This article presents an analysis of potential boundaries of lithostratigraphic terranes in the Sudetes and the Fore-Sudetic Block, confirmed by the waveforms of gravity horizontal gradients. Gravimetric modelling along the selected profile 3 makes it possible to present the subsurface geological structure. Metamorphic rocks of the Sowie Góry complex can probably reach a depth of almost 5 km on the Fore-Sudetic Block. Below them are mafic and ultramafic rocks, reaching a depth of up to 12 km, which belong to the Middle-Sudetic Ophiolite Complex. The kinematic data from the Sowie Góry metamorphic complex indicate displacement with the top-to-SW and to-S, as in theMiddle-Sudetic Ophiolite
Complex. Controversy over the origin and the geotectonic environment of the Early Ordovician protolith of the Sowie Góry gneisses, which are probably a magma product of arc-type magmatism formed above a subduction zone of the Tornquist Ocean. The Sowie Góry terrane can be considered as a relic of the Early Ordovician Paleozoic magma arc (the so-called peri-Baltic arc). The Sowie Góry terrane was moved towards the SW and S on obducted dismembered fragments of ophiolite sequences after closing the Rheic Ocean during the Eo-Variscan orogenesis.

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