THE NEUQUEN COMPOSITE SECTION: MAGNETOSTRATIGRAPHY AND BIOSTRATIGRAPHY OF THE MARINE LOWER JURASSIC FROM THE NEUQUEN BASIN (ARGENTINA)

IGLESIA LLANOS, MARÍA PAULA; RICCARDI, ALBERTO CARLOS

EARTH AND PLANETARY SCIENCE LETTERS

ELSEVIER SCIENCE BV

Lugar: Amstetdam, Holanda; Año: 2000 vol. 181 p. 443 - 457

0012-821X

Paleomagnetic and biostratigraphic data from from five marine sedimentary sections in the Argentine Neuquén basin have allowed to construct the Lower Jurassic Neuquén Composite Section. This composite section comprises 14 reversed and 11 normal polarity zones, in relation to 17 Andean ammonite Assemblage Zones, spanning the Hettangian-Toarcian (Early Jurassic). It represents the first paleomagnetic data of Lower Jurassic marine successions in the Southern Hemisphere. The Neuquén Composite Section was correlated to the International Mesozoic Polarity Time Scale (MPTS) which, for the Lower Jurassic, comprises 54 polarity zones and 16 Standard ammonite Zones. The correlation between the regional and the international biomagnetostratigraphic scales supports but also refines the correlation between the Andean and Standard ammonite zonations. Correlation between the Neuquén Composite Section and the polarity sequences recorded in each section helped to assign several unfossiliferous stratigraphical levels to the corresponding biozones.