A complete terrestrial Oligocene magnetobiostratigraphy from the Ebro Basin Spain

The integrated litho-, bio- and magnetostratigraphic cross-correlation of 11 continuous and correlatable sections in the southeastern Ebro Basin (NE Spain) produced a complete Oligocene magnetic polarity stratigraphy ranging from latest Eocene to earliest Miocene. The magnetic polarity zonation of the different alluvial and shallow lacustrine sections has been correlated to the GPTS using fossil mammals and the distinct sequence and pattern of polarity reversals. The composite magnetic polarity sequence defines a continuous sequence from Chron C15n to Chron 6Cn.2n, from 34.8 to 23.7 Ma (late Eocene¯early Miocene). In addition, a few short normal and reverse polarity events that correlate to cryptochrons in the GPTS are found (i.e. in C11n.1r and C8n.1r). The resulting regional magneto¯biostratigraphic framework based on fossil mammals is proposed to refine the dating of the European Oligocene biochronological mammal Paleogene units and correlate them with the standard Oligocene marine stages and the North American land mammal ages. The magnetochronology now established enables more precise dating of the late Eocene and Oligocene paleofloristic and paleofaunistic changes in southwestern Europe, which were coeval to ongoing global paleoclimatic and paleoceanographic changes on Earth caused by high latitude cooling and ice sheet development in eastern Antarctica.