title: Paleomagnetic constraints on the age of the Botucatu formation in Rio Grande do Sul, southern Brazil.
abstract: Paleomagnetic and rockmagnetic data are reported for the aeolian Botucatu Formation, in the southern Brazilian State of Rio Grande do Sul. Oriented samples were taken from a section located between the cities of Jaguari and Santiago. After thermal and alternating field demagnetization, both normal and reversed characteristic remanent magnetizations were found. These results yielded 13 reversed and 5 normal polarity sites, composing a magnetostratigraphic column displaying a sequence of reversed-normal-reversed polarity events. The paleomagnetic pole calculated for 18 sites is located at 114.7 degree E, 78.5 degree S (dp=8.1 masculine; dm=1.2 masculine), after restoring the strata to the paleohorizontal. This paleomagnetic pole indicates a Late Jurassic-Early Cretaceous age to the Botucatu Formation in the investigated area, and places the sampling sites at paleolatitudes as low as 21 masculineS.
authors.affiliation: Departamento de Geofísica, Instituto de Astronomia, Geofísica e Ciências Atmosféricas, Universidade de São Paulo, São Paulo, SP, Brasil.
authors.forename: Endale
authors.initials: E
authors.lastname: Tamrat
authors.forename: Marcia
authors.initials: M
authors.lastname: Ernesto