Abstract：The oolites, microbialites rock and oolitic shoal-microbial mound combinations widely developed in Cambrian Carbonates Formation. The analysis on oolitic shoal-microbial mound combinations can be used to judge Carbonate sedimentary environmental conditions and sedimentological systems characteristics, and reconstruct the Palaeogeography of sedimentary basins. Two sets of oolitic shoal-microbial mound combinations were recognized in the Mantou Formation MemberⅡ, Cambrian Series 3, Yiyang area, western Henan on the basis of field observation and indoor analysis, which are the combination of oolitic shoal-back shoal microbial mound and the combination of oolitic shoal-middle shoal ( back shoal) microbial mound. The oolitic shoal mainly includes radial-concentric ooids and radial ooids which formed in shallow oolitic shoal in the alternating weak and strong environment with cementation of micritic or microsparry calcite. The microbialites in microbial mounds include oncolite, stromatolite and thrombolite, which developed alternatively in the stratum in one or two types and combined calcified microbes such as Girvanella and Epiphyton. It could be found in low energy back-shoal ( or middle-shoal) intertidal zone or middle-shoal restricted sea. The changes of sea level and hydrodynamic condition greatly affected the development of oolitic shoal-microbial mound combination and the different microbialites in microbial mound.

Keyword：oolitic shoal;microbial mound;sea level change;Mantou formation Member Ⅱ;Yiyang area;