Palaeomagnetism of Permian Redbeds from the South-western United States

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Samples were collected from Permian redbeds of Guadalupian to Ochoan age at 61 sites in the south-western U.S.A. Upon thermal demagnetization, a stable primary component of magnetization could be isolated in most of the samples. Because of the elimination of most of the secondary component of magnetization, the grouping of the virtual pole positions is better than previous results have suggested. There is no apparent chronological migration of the pole position through Permian time. Measurement has shown that although most of the Permian rocks are reversely magnetized, the rocks from four formations appear to have stable primary components approximately anti-parallel to the directions of magnetization of the reversed rocks. These rocks are of middle Leonardian, late Guadalupian, and middle and late Ochoan ages and it is suggested that they represent three, and possibly four, normal polarity events during the Permian.