Fluvial networks of the Iberian Peninsula: a chronological framework

Abstract

Knowledge of the evolution of Spanish fluvial networks has improved during recent years as more river systems have been studied and
more geochronological data has become available. However, the chronological framework is a major issue as the range of applications is
limited by methodological constraints and spatial coverage is sparse. Integration of ‘absolute’ dating methods with biostratigraphy and
palaeomagnetism permits the recent evolution of these river systems to be reviewed. The timing of incision from the Late Neogene to the
present varies between the major Iberian fluvial systems, depending on the substrata and tectonic settings. Early Pleistocene and older
fluvial sequences in the core areas of the Iberian Peninsula provide a more extensive record of fluvial evolution and are better preserved
than the terrace flights in the coastal lowlands. Middle Pleistocene sequences are well developed in most of the major river systems in
Iberia, particularly those of the Tajo, Guadalquivir and Aguas River, and frequently represent the principal climatic cycles of that
period, although tectonic and sea-level effects can also be seen. For Late Pleistocene to Holocene times, the scheme becomes more
complex. Our review suggests that each river system has responded differently to local and regional climate control, glacial and
periglacial processes in headwaters in high mountain areas, glacio-eustatic sea-level changes and local and regional tectonic patterns.