The Bayanhot Basin is a Meso-Cenozoic faulted basin

which is superimposed on dis-tinct crystalline basement.With Chaxan fault as the boundary

the north of it is the stable Alxa Massif

and the south is the active Qilian folded belt.The structures within the basin are characterized by normal faults associated with rolling anticlines.A few thrusts and compressive folds are distributed mainly over thesouth part.The direction of the structures is NWW trending in the south part

NE in north-west and near SN in the east.In the Middle Proterozoic-Early Palaeozoic

the northwest Part of the basin wasrosen

the south part was the passive continental margin of Qilian trough

and east parta aulacogen.In the Late Palaeozoic

its south part was a foredeep and the east part wasa impactogen.The region was widely uplifted and magmations and faults occurred during the Permian-Triassic

marked the beginning of fragmentation of Alxa Massif.A lot of minor faulted basins separately occurred in the Jurassic.It became an unitary sedimentarybasin in the Early Cretaceous.At the end of Early Cretaceous

the basin uplifted again andthe activity diminished gradually.The Carboniferous source bed has so far been evidenced in the basin

discoveringmany oil-bearing formations in it.Therefore

the east and the south depressed zones withthick Carboniferous sediments are the most favourable region in oil and gas potential.