Classification and correlation of Cambrian in eastern Tarim Basin

Through the observation and analysis of the Cambrian profile of Kuruktag area in the northeastern Ta-rim Basin, combined with the comprehensive study on the Cambrian in the well YL1, and adopting the international Cambrian division scheme, it was proposed in this paper a new standard which divided Cambrian into four series and four formations. Two marking beds, "reversal spoon shaped gamma segment" and "ultra-high gamma segment", were identified. Multi fossils were found in large quantity in the Xishan Braque and Moheershan Formations. A great geological event (ZHUCE) was identified in the Lower Cambrian with global comparing significance. By comparing stratigraphic division, the early Cambrian formations were found missing in the wells TD1 and TD2, which were regarded as the typical wells of trough facies in Cambrian, indicating that the southern edge of the famous "Manjiaer aulacogen" had not reached the line from well TD1 to well TD2 at the end of Sinian. Four second-order and six third-order sequences in Cambrian were concluded in the study area, providing a stratigraphic basement for the studies of sedimentary facies, tectonic movement and hydrocarbon accumulation.