Development of the Cambrian subsalt structures in central Bachu area has mainly been controlled by fault movements.The present structural traps have been modified by multiphase tectonic movements.Kabei

Gudongshan and Karasay structures have reached their optimal trap shapes in Late Hercynian and Early Mesozoic

respectively.The structural traps have then been modified and destroyed by later structural movements

as a result

Kabei structure has been transformed from anticline into faulted anticline

while Karasay structure from anticline into faulted anticline and faulted nose.The closures of both structures have been reduced to some extent.In contrast

Gudongshan structure has lost the condition of forming relatively large local traps

because later faults have broken the original structural traps into strips

and the Himalayan tectonic movement has unevenly uplifted the structural belt and become low in the south and high in the north.Kangtakumu structural trap has been formed in a relatively short time

i.e.it has been formed in Middle Himalayan and strengthened in Later Himalayan stage

and the closure has also been enlarged.