Paleomagnetism and remagnetization of Upper Devonian synorogenic clastic sediments from the Pogorzała Formation (Świebodzice Depression, West Sudetes, Poland

Abstract

The Upper Devonian highly polymict conglomerates (site 26) and sandstones with clasts (site 27) of the Pogorzała Formation in the synorogenic Świebodzice Depression, West Sudetes, are hydrothermally altered and show signs of penetration by mineralized fluids. Nearly all the magnetic minerals present (mainly Fe-oxides and pyrrhotite accompanied by Fe-hydroxides) are of secondary origin. Rocks from each site carry multicomponent natural remanence composed of Mesozoic/post-Mesozoic and Palaeozoic components. In the conglomerates (site 26) two Palaeozoic components, labelled P and C, occur in the matrix and pebbles, whereas in the sandstones with large clasts (site 27) only one Palaeozoic component labeled C1 occurs. This means that the results of the conglomerate test for both sites are negative and the studied rocks were remagnetized during several remagnetization episodes. The overprints present in site 26 closely fit the reference data for the Baltica Plate for the Early Permian component (P) and Viséan component (C). The overprint present in site 27 is slightly shifted from the Westphalian (C1) segment of the reference path. The P component is also close to the path of polar wander for Variscan Europe.