Gondwanaland - massive shift at the beginning of the Cambrian!

14 Aug 2010

At www.sciencedaily.com/releases/2010/08/100810163456.htm a study published in Geology 2010: 38 (8), and a press release from Yale University, says the Gondwanaland supercontinent underwent a 60 degree rotation across the surface of the earth during the early Cambrian period. Yale geologists say that Gondwana, the southern  half of Pangaea, at the Cambrian Explosion (the sudden emergence of complex animal life forms), moved in a burst of activity from what they discovered by investigating the palaeo-magnetic record from the Amadeus Basin in central Australia. The direction of the magnetic field and a movement apparently much faster than plate movement allowed in the consensus model, has led to the possibility being considered that the poles shifted. The concept of plate movement is of course bound up with uniformitarian assumptions - the rate of movement, for example. The likelihood that the plates may have moved more quickly is considered by the authors less likely than the poles shifting - or this train of thought is a ploy to make it more likely that the poles moved, an idea they may favour. A change in the geographical poles is a subject that geologists have been arguing about amongst themselves - unbeknown to the rest of us. In fact, some geologists think polar wandering is a better model than what is usually assigned to plate tectonics - but the news release does not go into detail. What is now Brazil seems to have moved from a position near the South Pole to the tropics (but did it remain in the tropics?) when Brazil was part of Gondwanaland.