Abstract:

Relative sea level change may result in the change of water depth and all the other ecological factors related,so it is a key factor for controlling the succession and replacement of brachiopods communities. The speed and extension of sea level rising and descending greatly control the species richness and diversity of brachiopods community.In the area of the north margin of Turpan-Hami basin,totally three third-order relative sea level changes can be recognized from the Upper Carboniferous,and all the 5 brachiopods communinties developed during this period are closely related to the sea level risings.There is no brachiopods fossil found during the marine regression,this may result from the quick descending of relative sea level changes and too much clastic sediments warmed into. During the period of sea level rising,the rapid rising of primary sea level is in favor of early brachiopods communities but may restrain the development of later comers.Constant and slow rising of sea level is helpful to the flourish of the species richness and diversity of brachiopods，but may delay the process of the replacement of brachiopods communities.

Key words: Late Carboniferous, relative sea level change, brachiopods, Turpan-Hami basin