A palaeomagnetic survey of South American rock formations - Studies on rock formations from Northeast Brazil

• Published in: Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences
• Format: Article in Journal/Newspaper
• Language: English
• Published: The Royal Society 1970
• Subjects: American Rock; South Pole; South pole
• Online Access: http://dx.doi.org/10.1098/rsta.1970.0052; https://royalsocietypublishing.org/doi/pdf/10.1098/rsta.1970.0052

Devonian, Carboniferous and Xriassic formations from Piaui and Maranhao States in the northeast of Brazil have been studied and palaeomagnetic pole positions deduced. During the Devonian and Carboniferous the south pole appears to have moved away from S. America in a southeasterly direction from the vicinity of Rio de Janeiro: in the Triassic it was situated near the present position of the south pole relative to S. America. These results are in good agreement with those from other formations of the same age from other parts of the continent. Thermal cleaning has been carried out. The Devonian formations were almost completely remagnetized by the Mesozoic or Tertiary geomagnetic fields and the primary magnetization is very weak. Polar wander of 40 to 50° appears to have occurred during the time interval under investigation, i.e. M. Devonian to Triassic.