Utilize este identificador para referenciar este registo: http://hdl.handle.net/10400.21/1263
Título: Palaeomagnetism, rock magnetism and AMS of the Cabo Magmatic Province, NE Brazil, and the opening of South Atlantic
Autor: Font, E.
Ernesto, M.
Silva, P. F.
Correia, P. B.
Nascimento, M. A. L.
Palavras-chave: Magnetic fabrics and anisotropy
Palaeomagnetism applied to tectonics
Rock and mineral magnetism
Atlantic Ocean
South America
Isothermal Remanent Magnetization
K-AR Ages
Tectonic Implications
Acquisition Curves
Polarity Interval
Cretaceous Rocks
Africa
Egypt
Susceptibility
Basalts
Data: Nov-2009
Editora: Wiley-Blackwell Publishing, INC
Citação: Font E, Ernesto M, Silva, P F, Correia P B, Nascimento M A L.Palaeomagnetism, rock magnetism and AMS of the Cabo Magmatic Province, NE Brazil, and the opening of South Atlantic. Geophysical Journal International. 2009; 179 (2): 905-922.
Relatório da Série N.º: 2;
Resumo: P>Reconstruction of the South Atlantic opening has long been a matter of debate and several models have been proposed. One problem in tracing properly the Atlantic history arises from the existence of a long interval without geomagnetic reversals, the Cretaceous Normal Superchron, for which ages are difficult to assign. Palaeomagnetism may help in addressing this issue if high-quality palaeomagnetic poles are available for the two drifting continental blocks, and if precise absolute ages are available. In this work we have investigated the Cabo Magmatic Province, northeastern Brazil, recently dated at 102 +/- 1 Ma (zircon fission tracks, Ar39/Ar40). All volcanic and plutonic rocks showed stable thermal and AF demagnetization patterns, and exhibit primary magnetic signatures. AMS data also support a primary origin for the magnetic fabric and is interpreted to be contemporaneous of the rock formation. The obtained pole is located at 335.9 degrees E/87.9 degrees S (N = 24; A(95) = 2.5; K = 138) and satisfies modern quality criteria, resulting in a reference pole for South America at similar to 100 Ma. This new pole also gives an insight to test and discuss the kinematic models currently proposed for the South Atlantic opening during mid-Cretaceous.
Peer review: yes
URI: http://hdl.handle.net/10400.21/1263
ISSN: 0956-540X
Aparece nas colecções:ISEL - Eng. Civil - Artigos



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