International Geological Journal - Official Journal of the Carpathian-Balkan Geological Association

PALEOMAGNETIC AND ROCK MAGNETIC PROPERTIES OF THE LOWER PALEOZOIC METAMORPHIC COMPLEX OF THE RUDAWY JANOWICKIE (WEST SUDETES, POLAND)

Pages: 283 - 294

Authors: MARIA JELENSKA, TOMASZ WERNER, STANISLAW MAZUR

Abstract: The Lower Paleozoic Rudawy Janowickie Metamorphic Complex represents the eastern part of the Izera-Karkonosze Massif in the West Sudetes (NE Bohemian Massif). It comprises a nappe pile overthrust towards the NW onto the pre-Variscan continental basement of the Saxothuringian Basin. The complex consists of three units: (1) Leszczyniec Unit composed of metabasites and gneisses, (2) Izera-Kowary Unit consisting of gneisses and mica schists and (3) the South Karkonosze (Niedamirów) Unit consisting of greenstones and phyllites. These rocks underwent multistage deformation mostly accompanied by epidote-amphibolite grade metamorphism of the Late Devonian to Early Carboniferous age. Rock magnetic study revealed magnetic and hematite as carriers of remanence accompanied by maghemite and sometimes by goethite. Several high stability components of characteristic remanent magnetization (ChRM) of predominantly reversed polarity were found. The shallow directions of remanence were interpreted as Carboniferous overprint on the basis of the similarity of their pole position to the Carboniferous segment of the Apparent Polar Wander Path (APWP) for Baltica. The position of paleopoles derived from the steep directions corresponds well with the Silurian segment of the APWP for Baltica assuming the anticlockwise rotation of the Rudawy Janowickie Complex by the angle of ca. 90º. The paleolatitude derived from these directions after averaging corresponds well to the Silurian data for the Bohemian Massif. The possibly Early Paleozoic directions were found in different rock types: metabasites, gneisses and limestones from the Leszczyniec and Izera-Kowary Units. However, the scatter of the Kmax and ChRM along similarly oriented girdles may suggest that the deformation influenced the NRM directions.

Keywords: Paleozoic, matamorphic complex, paleomagnetism, rock magnetism

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