Związek ofiolitu Ślęży z waryscyjską strukturą metamorfiku sowiogórskiego
Abstract
CONNECTION OF THE ŚLĘŻA OPHIOLITE WITH THE VARISCAN STRUCTURE OF THE SOWIE MEIAMORPHIC ROCKS
Summary
The structural analysis made in the area of about 100 sq km of the Sowie Mountains metamorphic segments (the Middle Sudety Mountains - the lower Silesia) shows that the main fold macrostructures developed in the second deformation phase (D2). The basic influence on geometry, size and orientation of microfolds (F2) had thrust sheets of basic rocks - mainly amphibolites. The most basic and ultrabasic rocks developed from segments of the former ocean crust (the Ślęża ophiolite).
As a results of long standing tectonic processes (beginning in the Cadomian tectogenesis and lasted to lower Carboniferous) on the margins of the Bohemian Massif (in the Saxo-Turonian zone), mutual displacements of various segments of continental (Cadomides) and ocean crusts (e.g. the Ślęża ophiolites) took place.
From the ocean crust undergoing subduction beneath the Bohemian Massif a large segment (the Ślęża ophiolite) was tectonically detached. This ophiolite thrust sheet impressed in existing structural discontuities of the Cadomides.
Concomitance of subduction and obduction processes resulted in decreasing the rate of overthrust of this segment of the Bohemian Massif on the ocean crust. The rate of overthrust of the whole Bohemian Massif was not decreased.
Originated in that way the disagreement in displacement rates caused detachment and overthrust the Sowie Mountains sheets (northward) on the overthrusting (southward) the Ślęża ophiolite. As the result of this process the thickness and weight increased in this marginal part of the Bohemian Massif. It caused submerging the whole zone (much more in the eastern part) and development among others migmatites and locally granitoids during the third deformation phase (D3). The Sowie Mountains structure is characterized by the tectonic macromelange pattern.
Thrust sheets, thrust slices, boundins, lens of ophiolite segments, numerous in the lower part of the Sowie Mountains slab characterize this type of pattern.
These macrostructural features originated in the Variscan tectogenesis (the Acadian phase?).
Summary
The structural analysis made in the area of about 100 sq km of the Sowie Mountains metamorphic segments (the Middle Sudety Mountains - the lower Silesia) shows that the main fold macrostructures developed in the second deformation phase (D2). The basic influence on geometry, size and orientation of microfolds (F2) had thrust sheets of basic rocks - mainly amphibolites. The most basic and ultrabasic rocks developed from segments of the former ocean crust (the Ślęża ophiolite).
As a results of long standing tectonic processes (beginning in the Cadomian tectogenesis and lasted to lower Carboniferous) on the margins of the Bohemian Massif (in the Saxo-Turonian zone), mutual displacements of various segments of continental (Cadomides) and ocean crusts (e.g. the Ślęża ophiolites) took place.
From the ocean crust undergoing subduction beneath the Bohemian Massif a large segment (the Ślęża ophiolite) was tectonically detached. This ophiolite thrust sheet impressed in existing structural discontuities of the Cadomides.
Concomitance of subduction and obduction processes resulted in decreasing the rate of overthrust of this segment of the Bohemian Massif on the ocean crust. The rate of overthrust of the whole Bohemian Massif was not decreased.
Originated in that way the disagreement in displacement rates caused detachment and overthrust the Sowie Mountains sheets (northward) on the overthrusting (southward) the Ślęża ophiolite. As the result of this process the thickness and weight increased in this marginal part of the Bohemian Massif. It caused submerging the whole zone (much more in the eastern part) and development among others migmatites and locally granitoids during the third deformation phase (D3). The Sowie Mountains structure is characterized by the tectonic macromelange pattern.
Thrust sheets, thrust slices, boundins, lens of ophiolite segments, numerous in the lower part of the Sowie Mountains slab characterize this type of pattern.
These macrostructural features originated in the Variscan tectogenesis (the Acadian phase?).