Paleomagnetism and rock magnetism of the Neoproterozoic Itajai Basin of the Rio de la Plata craton (Brazil): Cambrian to Cretaceous widespread remagnetizations of South America

Autor(es)

Font, E. ^[1] ; Ponte Neto, C. F. ^[2] ; Ernesto, M. ^[2]

Afiliação do(s) autor(es)

^[1] Univ Lisbon, Inst Dom Luiz, P-1749016 Lisbon - Portugal

^[2] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: GONDWANA RESEARCH; v. 20, n. 4, p. 782-797, NOV 2011.
• Citações Web of Science: 8

Resumo

A detailed rock magnetic and paleomagnetic study was performed on samples from the Neoproterozoic Itajai Basin in the state of Santa Catarina, Brazil, in order to better constrain the paleogeographic evolution of the Rio de la Plata craton between 600 and 550 Ma. However, rock magnetic properties typical of remagnetized rocks and negative response in the fold test indicated that these rocks carried a secondary chemical remanent magnetization. After detailed AF and thermal cleaning, almost all samples showed a normal polarity characteristic remanent magnetization component close to the present geomagnetic field. The main magnetic carriers are magnetite and hematite, probably of authigenic origin. The mean paleomagnetic pole of the ltajai Basin is located at Plat= -84 degrees, Plong = 97.5 degrees (A95 = 2 degrees) and overlaps the lower Cretaceous segment of the apparent polar wander path of South America, suggesting a cause and effect with the opening of the South Atlantic Ocean. A compilation of remagnetized paleomagnetic poles from South America is presented that highlights the superposition of several large-scale remagnetization events between the Cambrian and the Cretaceous. It is suggested that some paleomagnetic poles used to calibrate the APWP of Gondwana at Precambrian times need to be revised; the indication of remagnetized areas in southern South America may offer some help in the selection of sites for future paleomagnetic investigations in Precambrian rocks. (C) 2011 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. (AU)

• Processo FAPESP: 06/02965-0 - Estudo paleomagnético das bacias vulcano-sedimentares do Paraná e de Santa Catarina, Brasil: calibração da curva de deriva polar aparente para a América do Sul no fim do Neoproterozóico
• Beneficiário: Tiago dos Anjos Costa
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 96/09619-6 - Estudo paleomagnético de rochas magnéticas cambrianas da Plataforma Sul-Americana
• Beneficiário: Cosme Ferreira da Ponte Neto
• Modalidade de apoio: Bolsas no Brasil - Doutorado