The Neoproterozoic Gaoyuzhuang dolomite from Beipiao area, western Liaoning Province was systematically studied based on outcrop and microscope observations. The whole section is composed of several cyclic shallowing upward units (subsequences), which include subtidal massive dolomite and intertidal thin-bedded dolomite. Three types of microfacies, microspar dolomite, dolomicrite and intraclast dolomite, were identified. Partial recrystallization and silica filling/replacement are associated with each microfacies. The chert bands and
nodules, which are commonly distributed along the stratigraphic layers, was probably formed during the syndepositional stage. Silica filling/replacement may have great contributions to dolomite dissolution and recrystallization and therefore improve the porosity of the dolomite, potentially leading to the formation of the excellent dolomite reservoir. Therefore, silica filling/replacement during the syn-depositional stage is significant for the development and evolution of dolomite reservoirs.