Drill core analysis showed 41 sedimentary cycles in the sedimentary association of the Neogene to Quaternary Florina Basin. With a total thickness up to 560 m. The lower part is the Base formation with an up to 297m thick, whereas middle part, Vei formation is u t 127m thick and the upper part which corrresponds to Lophon formation is up t 124m thick. The beginning of sedimentation in the basin, with alternated sand, clay and conglomeratic beds, with presence of xylite, at the lowermost part of Base formation, indicates a weak tectonic activity and low sedimentation rate. Tectonic activity increased and alluial fans were formed in the rest part of Base formation. The 21 cycles within alluvial fans could be related mostly with 21 episodes of tectonic activity and sedimentation and less with climatic changes or auto cyclic eents. Depositional environment changed in the Vevi formation from terrestrial to lacustrine, where lacustrine and fluvio-lacustrine deposits were accumulated. Fnall, the basin filled up with terrestrial deposits in the Lophon formation. So, the ratio of subsidence rate/sedimentation rate starts with, <1 in Base /formation, becomes =1 in the case of Vevi's formation and finally becomes again <1 in Lophon formation. Fluvial and alluvial fan environments can be used as CO2 storage sites, whereas the internal change of stratigraphy in the same environment of sedimentation does nt allow the escape of CO2.

Keywords: sedimentary ccles, alluvial fans fluvio - lacustrine environment