As a result of the early Hercynian Movement

the latest Middle Devonian tectonic unconformity is one of the most important unconformities in Tarim basin.It is widely distributed in the basin

occurring in the forms of superimposed unconformity

high angle unconformity

parallel unconformity

and conformity from the uplifted area to the depression.The underlying strata in Tabei and Tazhong areas were eroded severely and were accompanied by deposition and onlapping of the Donghe sandstone along the unconformity in Late Devonian

forming several erosional unconformity triangle zones and onlapping unconformity triangle zones.The distribution and structural styles of the unconformity are the results of tectonic movement and controls the distribution of the favorable stratigraphic traps.The erosional unconformity triangle zones are the potential areas for the Silurian lithologic traps

while the onlapping unconformity triangle zones are regarded as the favorable areas for the Devo-nian Donghe sandstone lithologic traps.