Resultados paleomagnéticos de los depósitos pliopleistocenos de la cuenca de Palma (Mallorca, España)

Abstract

The results from the paleomagnetic analysis of the plio-pleistocene deposits located in the eastern (Bahia Azul Section) and western (Banc d'Eivissa) borders of the Palma Basin are presented in this paper. The Bahia Azul section is composite by a marine terrace at +70-74 m a.s.1., overlapped by nine littoral dune systems separated by erosional surfaces. The Banc d'Eivissa section is constituted of a lower marine terrace at +24-25 m a.s.l., buried by two dune systems, although there are more numerous in the vicinity. The lithological spectrum at both sections holds a main calcarenitic nature, but the available outcrops display a different degree of weathering making difficult the establishment of a continuous magnetoestratigraphic sequence. The paleontological content (Rosello y Cuerda, 1973) and paleomagnetic results of the Banc d'Eivissa deposits are no sufficient to establish a precise chronological sequence, and only is possible to locate them within the reverse polarity Matuyama epoch. On the contrary, the lower half of the Bahia Azul sequence (marine terrace plus the 3 first dune systems) presents a consistent reverse polarity. The paleontological content of these materials indicates an early Pleistocene age (Emilian cycle: Cuerda y Sacares, 1992) which agree with the obtained paleomagnetic results. Therefore, the whole sequence is interpreted to be located between the normal polarity chrons of Jaramillo and Olduvay (Clr. 1n and C2n of Cande and Kent, 1995) within the Matuyama epoch, but can not be totally rejected the possibility that them could be placed after the Olduvai Chron.