Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1045046 | Quaternary Research | 2015 | 17 Pages |
Abstract
The drainage area of the Iberian Ranges (NE Spain) houses one of the most extensive Quaternary fluvial tufaceous records in Europe. In this study, tufa deposits in the Añamaza, Mesa, Piedra and Ebrón river valleys were mapped, stratigraphically described and chronologically referenced from U/Th disequilibrium series, amino acid racemization and radiocarbon methods. Tufa deposits accumulated in cascades, barrage-cascades and related damming areas developed in stepped fluvial systems. The maximum frequency of tufa deposition was identified at 120Â ka (Marine Oxygen Isotope Stage [MIS] 5e), 102Â ka (MIS 5c), 85Â ka (~Â MIS 5a) and 7Â ka (MIS 1), probably under warmer and wetter conditions than today. Additional phases of tufa deposition appear at ~Â 353Â ka (~Â end of MIS 11), 258-180Â ka (MIS 7) and 171-154Â ka (MIS 6). Although most tufa deposition episodes are clearly correlated with interstadial periods, the occurrence of tufa deposits during the penultimate glaciation (MIS 6) is remarkable, indicating that the onset of this stage was climatically favourable in the Iberian Peninsula. Biostatic conditions and the dynamics of karstic systems regulating tufa deposition seem to be sensitive to the precipitation regime, controlled by shifts in the position of North Atlantic atmospheric belts, and summer insolation, regulated by orbital forcing.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geology
Authors
Carlos Sancho, Concha Arenas, Marta Vázquez-Urbez, Gonzalo Pardo, MarÃa Victoria Lozano, José Luis Peña-Monné, John Hellstrom, José Eugenio Ortiz, MarÃa Cinta Osácar, Luis Auqué, Trinidad Torres,