New late Paleozoic paleopoles from the Donbas Foldbelt (Ukraine): Implications for the Pangea A vs. B controversy

作者：Meijers Maud J M^*; Hamers Maartje F; van Hin**ergen Douwe J J; van der Meer Douwe G; Kitchka Alexander; Langereis Cor G; Stephenson Randell A

来源：Earth and Planetary Science Letters, 2010, 297(1-2): 18-33.

DOI：10.1016/j.epsl.2010.05.028

• paleomagnetism
• plate reconstructions
• Pangea
• Eurasia
• inclination shallowing
• Paleozoic

The Carboniferous to early Permian apparent polar wander (APW) path for Eurasia is not well constrained, because of the paucity of reliable paleomagnetic poles. This is at least partly responsible for the Pangea A vs. B controversy in the early Permian: is the overlap between the northern and southern continents during the early Permian caused by a lack of reliable paleomagnetic data (Pangea A) or must a large displacement along a mega-shear zone be invoked (Pangea B)? Here, we present results from six paleomagnetic sampling sites ranging in age from the early Carboniferous to the early Permian from sedimentary rocks in the Donbas Foldbelt (Ukraine) to improve the Carboniferous early Permian APW path for Eurasia and to contribute to solving the Pangea A vs. B controversy. Six time intervals were sampled in the Donbas Foldbelt (eastern Ukraine), which was filled with sediments and volcanic units during the late Devonian to Permian syn- and post-rift subsidence phases. We present results from sediments that were corrected for inclination shallowing with the elongation/inclination (E/I) method. We conclude that there is a general northward movement of the Donbas Foldbelt: the resulting paleolatitudes are slightly but generally significantly higher than expected from existing APW paths. The late Carboniferous to early Permian data provide three new reliable paleopoles for Eurasia. The early Permian pole does not necessarily require a Pangea B reconstruction. It results in higher paleolatitudes for Laurussia in the early Permian and removes the overlap between Gondwana and Pangea. We also reconstructed the position of Laurussia based on Carboniferous Laurentian poles recently corrected for inclination shallowing, which clearly favours a Pangea B configuration. It seems that the Pangea A vs. B debate is as lively as before. The three early Carboniferous paleopoles give reliable paleolatitudes, but declinations significantly deviate from the expected directions. We argue that the southernmost part of the Donbas Foldbelt underwent a counterclockwise rotation, related to Mesozoic compressional events that are recognised in paleostress analyses.

• 出版日期2010-8-15