In this Phd thesis, various climatic and environmental tracers will be retrieved from the deepest 200m of the EPICA Dome C ice core which covers the period from 600 000 to 800 000 years before today. Specifically, we will study the elementary and isotopic composition of O2 in the air trapped in the ice as a dating approach, as well as the water isotopic composition in order to reconstruct the high frequency temperature variations. In collaboration with the Institute of Geosciences and Environment (Grenoble, France), we will study how the diffusion and thinning processes affect the greenhouse gases (CH4 and CO2) concentration. This PhD project include an analytical part of ice core analysis, as well as interpretation of the results using simple models of the diffusion processes on the ice core signal. The results obtained on the EPICA Dome C ice core will then be generalised to the Beyond EPICA ice core currently being drilled. This project targets a student interested by paleoclimate studies with strong basis in Physics and/or Geosciences. Strong teamwork skills will be required with collaborations outside of LSCE in France or abroad. A proficient English level is needed (French optional). This project is funded by the ANR project ToBE, with strong links with the european project Beyond EPICA.