LATE CRETACEOUS ALKALINE COMPLEXES, SOUTHEASTERN BRAZIL - PALEOMAGNETISM AND GEOCHRONOLOGY

Late Cretaceous alkaline rocks from Pocos de Caldas, Itatiaia, Passa Q uatro and Sao Sebastiao Island were studied with the main purpose of i mproving the South American apparent polar wander path (APWP). Rb-Sr a ge determinations for Passa Quatro and alkaline stocks from Sao Sebast iao Island are around 70 and 81 Ma respectively. The magnetic carriers in the rocks studied were maghemite and highly oxidized titanomagneti tes. The paleomagnetic poles obtained in this work are 320.1 degrees E , 83.2 degrees S (N = 47, A(95) = 2.7 degrees, K-SC = 2609.8) for Poco s de Caldas, 360.0 degrees E, 79.5 degrees S (N = 18, A(95) = 5.7 degr ees, K-SC = 607.4) for Passa Quatro and Itatiaia, and 331.9 degrees E, 79.4 degrees S (N = 18, A(95) = 4.9 degrees, K-SC = 862.4) for Sao Se bastiao Island (the ISLAND set).