Resumen de Cronología del sistema de terrazas cuaternarias en la cuenca del rio Cinca (Pirineos y Depresión del Ebro)
Carlos Sancho Marcén, Edward Rhodes, José Luis Peña Monné, Eric V. McDonald, Claudia J. Lewis, Emilio L. Pueyo Morer, John Gosse
A stepped sequence of cut-in-bedrock or strath terraces has been developed in the Cinca River valley during Quaternary times, as a consequence of both Pyrenean post-orogenic flexural uplift and regional climatic changes. A sequence including ten terrace levels (from Qt1 to Qt10) with extensive outcrops in the lower sector of the drainage basin (Monzón-Fraga reach), as well as in the upper sector (around Aínsa), has been differenciated. Reverse polarities deduced from paleomagnetic analysis suggest older ages than the Matuyama-Brunhes limit for the Qt1 and Qt2 terraces. Terrestrial cosmogenic data and normal magnetic polarity suggest that the Qt3 may be 600 ka old. Terraces Qt5, Qt6, Qt7, Qt8 y Qt9 yield weighted mean ages of 176±14, 97±16, 64±4, 41±8 to 49±4 and 16.6±0.1 to 11.1±0.8 ka, respectively, by using optically stimulated luminescence (OSL) and radiocarbon techniques. Medium-Upper Pleistocene morphosedimentary records in the Cinca River valley could be related to cold climatic stages and constitute a chronological sequence of reference in adjacent basins of the NE Spain.
