Chronologie et enregistrements climatiques dans les dépôts travertineux du Maroc

Establish an accurate chronological frame for the climatic proxies remains an important issue. The chronology of calcitic deposits (speleothems and travertines) can be of great help for modeling the various mechanisms which control the climatic variations in Northwestern Africa in isotopic stratigraphic scale based on oxygen isotopes variations. Travertines can be dated using several methods among them the radiocarbon, uranium-series, Electron Spin Resonance and magnestratigraphy. The dating results obtained on hydrothermal or fluvial travertines taken on 24 sites spread on Moroccan territory are presented in this article. Sites in which the oldest human bearing occupations are attributed to the Middle Pleistocene are given priority. Our results show that travertines formed from Lower Pleistocene, around the Middle Plesitocene Transition (MPT), which occurred between 1.2 and 0.7 Ma, and today. The second major information demonstrates that these formations grew during even or odd isotopic stages both in hydrothermal and fluvial travertines, from the beginning of Brunhes epoch thanks to palaeomagnetic data.