Cambrian Sequence Stratigraphic Framework in Tarim Basin

Synthesizing the sequences characteristics of outcrop,drilling log and seismic data,the 3rd order sequence stratigraphic framework of Cambrian in Tarim basin has been established,and the Cambrian can be divided into six 3rd order sequences tracing and correlating in whole Tarim basin. Contrasting and analyzing between carbon isotope cycles of whole rock reflecting global sea level change or eustatic change and sedimentary cycles reflecting depositional water depth,the 3rd order sequences of Cambrian in Tarim basin may be divided into 2 types as eustatic sequence (sequence CSQ2,CSQ4,CSQ5,CSQ6),of which formation chiefly controlled by eustatic change,and tectonic sequence (sequence CSQ1,CSQ3),of which formation chiefly controlled by regional tectonic subsidence. The Cambrian platform margin in Lunnan area,northern Tarim basin,was generally behaved as evolution from ramp in Early Cambrian to rimmed platform in Middle—Late Cambrian,and progradational stacking style from west to east,it's speculated mainly related to faint eustatic fall in Cambrian and general stable and little tectonic subsidence in Tarim basin.