Abstract: The Duyun Movement is the most prominent in the south of Guizhou Province and has been studied and accep-ted widely.However,the study on its geological performance and effect within the Sichuan Basin were seldom documented.Unconformity description based on outcrop,drilling and seismic data shows that there is an obvious angle unconformity between the Upper Ordovician Baota Formation and its overlying strata but no obvious angle unconformity is recognized between the Permian and the Silurian in the central and west of the Sichuan Basin,which means the Duyun Movement was the key tectonic movement effecting the formation of Chuanzhong paleo-uplift,the Kwangsian Orogeny occurred at the end of the Silurian did not cause any folding in central even the whole Sichuan Basin.The Duyun movement caused the exposure and erosion of the Ordovician Baota Formation in northwest of the Sichuan Basin,which constitute,together with the overlying Lower Silurian source rock,a new hydrocarbon accumulation model of upper source rock and lower reservoir.The movement also caused the formation of fractures in the core and flank area of Chuanzhong paleo-uplift and strengthened the formation of karst in the Sinian-Ordovician.It is proved that the Sinia-Ordovician karst reservoirs are well developed in areas covered by the Silurian around the Chuanzhong paleo-uplift,which are favorable exploration areas.

Key words: unconformity, karst, Ordovician, Duyun Movement, Sichuan Basin