La inversión Matuyama-Brunhes en la secuencia de terrazas del río Jarama entre Velilla de San Antonio y Altos de la Mejorada, al SE de Madrid (España)

Abstract

To the east of Madrid city in the Jarama river valley and between Mejorada del Campo and Velilla de San Antonio, we have studied the paleomagnetic properties of the river terrace sequence in the M-203 highway, located between El Rasillo and Altos de La Mejorada. Over a new geomorphological mapping the alluvial plain at +4-5 m and terraces at +20 m, +30-35 m, +60-65 m, +85-90 m, +105-110 m and +125-130 m have been defined. Five terraces have been sampled with the exception of the terrace at +20 m, allowing to place those terraces at altitudes greater or equal to +60-65 m in the Matuyama Chron, while terraces at +20 m and +35 m belong to Brunhes Chron. ESR datings on terraces in the Arlanzón river valley in Burgos (Moreno et al., 2012), suggest that Matuyama-Brunhes inversion in the Jarama valley could be established between the end of the sedimentation of the +60-65 m terrace and the engagement of subsequent +50-55 m terrace, located upstream from Mejorada del Campo, in Marchamalo (Pérez- González, 1994).