The Case for Pangea B, and the Intra‐Pangean Megashear

摘要: In the mid-1950s we discovered that paleopoles determined from rocks of Late Carboniferous through Triassic age Europe and North America agreed after closure Atlantic. By contrast, Australian same geological systems, although they were brought closer when reassembled into traditional Pangea configuration (Pangea A), still differed by 15°-20°. This anomaly, Intra-Pangea Paleomagnetic (IPP) anomaly has now been found throughout Gondwana. It can be explained placing Gondwana 3-4000 km further east north with respect to Laurasia, without ocean between them. is B. Between Early Permian Epochs, B was transformed A ∼3500 dextral shear (Intra-Pangea Megashear) following line mid-Carboniferous Appalachian-Variscan orogenic belt. The precise timing megashear uncertain. Several difficulties have raised. has, minor adjustment, kept intact, IPP invoking one or more following: presence large, long-term, zonal octupole components in geomagnetic field during Periods, errors reconstructing continents, inclination dating, isolating original magnetizations. past several years, observations, especially western Mediterranean region, have, I believe removed each these possibilities as sole causes anomaly. However, this does not mean that, future, new difficulties, old combination, will raised, but it mean, on basis present evidence, ideas Intra-Pangean Megashear survive are germane discussions end-Paleozoic geology.