METER-SCALE CARBONATE CYCLES IN THE BACHU FORMATION OF THE LOWER CARBONIFEROUS IN THE TARIM BASIN

Two kinds of meter-scale carbonate cycles are developed in the Bioclastic Limectone Member of the Bachu Formation in the Lower Carboniferous of the Tarim Basin,i.e. the intertidal-supratidal cycle and the subtidal-supratidal cycle.According to the characteristics of sedimentology and the analysis of the Fischer Plot, the cycles are formed in the upland system domain of the 3^rd order sequence and controlled by Milankovitch-induced high-frequency sea-level fluctuation. The dolomitic limestone reservoirs developed with needlehole-like solution openings may be related to the short-term exposure of carbonate platforms caused by the high-frequency sea-level fluctuation.