Paleomagnetic investigations of the Carboniferous sediments from the Intra-Sudetic Basin, southern Pland. Part II: Namurian-Westphalian deposits

Paleomagnetic and rock-magnetic study presented here concern the Upper Carboniferous (Namurian-Westphalian) sediments from the Intra-Sudetic Basin in the western Sudetes. The sampled rocks belong to the Wałbrzych (CW), Biały Kamień (CB) and Zacler (CZ) formations. Rock-magnetic investigations reveal presence of a small amount of magnetite and maghemite in pseudosingle-domain (PSD), single-domain (SD) and rarely multi-domain (MD) grains accompanied with goethite and hematite. Several groups of natural remanent magnetization (NRM) components were isolated from the demagnetization results; three of them, labeled T, A and A1, can be interpreted in terms of the geomagnetic field; the T component is a Mesozoic (or recent) overprint; the A component with the mean direction of D = 190°, I = -13° and the Virtual Geomagnetic Pole (VGP) Lat = 45°N and Long = 181°E is the post-tilting Autunian-Saxonian overprint; and A1 component with the mean direction of D = 196°, I = 24° and the VGP of Lat = -25°N and Long = 358°E is the pre-tilting one fitting the Westphalian segment of the APWP of Baltica. The origin of the remaining components, labeled B and C, is still an open question. Results of this study suggest that the investigated area has not undergone any important rotation since the Westphalian time.