The development of the fluvial network in the Ebro Basin started more than 1 million years ago

A research team recently published the first numerical dating study of the oldest fluvial terraces of the Alcanadre River (Spain)

A research team led by Mathieu Duval, from the Centro Nacional de Investigación sobre la Evolución Humana (CENIEH, Spain) and The Australian National University (ANU, Australia), and Carlos Sancho from the Department of Earth Sciences of the University of Zaragoza (Spain) recently published a work in Quaternary Geochronology focused on the numerical dating of the oldest fluvial terrace deposits associated to the River Alcanadre (Ebro Basin, Spain).

These are basically the first numerical ages obtained for such old fluvial archives in the area. Age results provide an Early Pleistocene chronology indicating that deposits are at least 800,000 years old. Furthermore, they suggest that the development and incision of the actual fluvial network of the Ebro basin started at least 1.3 Million years ago.

Fluvial terrace sequences are known to be valuable Quaternary continental archives that can record regional paleoclimatic, palaeoenvironmental or paleogeographic fluctuations during the Quaternary (last 2.6 million years).

Electron Spin Resonance (ESR) Dating

In the present work, the authors dated the earliest remnants of Quaternary fluvial activity in the Ebro basin after its opening to the Mediterranean Sea during the end of the Tertiary.

Electron Spin Resonance (ESR) dating method was applied to optically bleached quartz grains following an approach based on the simultaneous measurement of different signals in a given sample.

According to Mathieu Duval, “these results do not only provide key chronological information about the evolution of the Ebro Basin during the Quaternary, but also demonstrate the interest of using this approach to date Early Pleistocene fluvial deposits”.

The work opens some interesting perspectives in the future for dating the earliest fluvial remnants of other Quaternary basins in Europe that are currently lacking numerical ages.