Palaeomagnetism and the age of the Cracow volcanic rocks (S Poland)

Permian rhyodacites, melaphyres and tuffs from the Cracow area (South Poland) were sampled for the palaeomagnetic and isotope studies. Single-grain U-Pb dating of most zircon grains separated from the rhyodacites gave mean age of magma emplacement of 294.2 ± 2.1 Ma. Some zircons, however, displayed...

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Bibliographic Details
Published in:Geophysical Journal International
Main Authors: Nawrocki, J., Fanning, Christopher, Lewandowska, A., Polechonska, O., Werner, T.
Format: Article in Journal/Newspaper
Language:unknown
Published: Blackwell Publishing Ltd
Subjects:
Keywords: apparent polar wander path
dacite
emplacement
Hercynian orogeny
magma
magnetization
paleomagnetism
Pangaea
Permian
strike-slip fault
tuff
uranium-lead dating
volcanic rock
zircon
Central Europe
Cracow
Eurasia
Europe
Malopolskie
Poland Continental tectonics: Strike-slip and transform
Palaeomagnetism applied to tectonics
Fennoscandian
Online Access:http://hdl.handle.net/1885/37758
https://doi.org/10.1111/j.1365-246X.2008.03804.x
https://openresearch-repository.anu.edu.au/bitstream/1885/37758/5/FanningCM_RSES_2008_Nawrocki_Palaeomagnetism_and_the_age.pdf.jpg
https://openresearch-repository.anu.edu.au/bitstream/1885/37758/7/01_Nawrocki_Palaeomagnetism_and_the_age_of_2008.pdf.jpg
Description
Summary:Permian rhyodacites, melaphyres and tuffs from the Cracow area (South Poland) were sampled for the palaeomagnetic and isotope studies. Single-grain U-Pb dating of most zircon grains separated from the rhyodacites gave mean age of magma emplacement of 294.2 ± 2.1 Ma. Some zircons, however, displayed younger ages (268.7 ± 3.4 Ma), probably related to the metasomatic alterations of these rocks. Two Permian components of magnetizations related to these processes were isolated and together with previously defined Late Carboniferous-Permian palaeomagnetic poles from South Poland were used for construction of the regional apparent polar wander path (APWP). The Early Permian segment of this APWP shows a certain departure from the coeval part of the Fennoscandian APWP due to anticlockwise rotations of studied rocks most probably caused by mid-Permian sinistral tectonic movements along reactivated prominent Variscan faults of Central Europe. This sense of tectonic mobility does not support the hypothesis about transformation from Pangea 'B' to Pangea 'A' along an intra-Pangea dextral megashear during the Permian. Older than previously assumed ages of the post-Variscan igneous rocks of Central Europe reduce overlap of Gondwana's and Laurussia's parts of the Early Permian Pangea 'A'.

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