Geologically, the rock mass of the Mogao Grottoes is semi-binder calcirudite of the quaternary sediment of very loose structure.

莫高窟体在上属第四纪沙泥、钙半胶砾，构十分松散。

Mainly developed are fan - delta, deep lake turbidite and calcirudite deposit, and also alluvial fan deposit in early period.

各时期形成的砂和粒储集体,为油气储集提供了有利的场所。