Sequence stratigraphic analysis of the Sinian strata in the Aksu region, Xinjiang

The depositional systems in the Sinian Linkuanggou section in the Aksu region, Xinjiang may fall into the littoral, siliciclastic tidal-flat and carbonate tidal-flat depositional systems. These depositional systems have recorded the evolution from the siliciclastic rock systems to the carbonate rock systems of the Sinian strata in the Aksu region. Four types of sequence boundaries are recognized for the field outcrops, including the transgressive onlap unconformity, transgressive erosional scour surface, lithologic-lithofacies transitional surface and exposure erosional surface. Two second-order sequences and five third-order sequences are also discriminated for the Sinian strata. The supersequence I represented by the Sugaitebulake Formation comprises the sequences SQ1, SQ2 and SQ3, and the supersequence II represented by the Qigebulake Formation comprises the sequences SQ4 and SQ5. The multiphase tectonic movements are interpreted as the major controlling factor for the formation, development and evolution of the sequence stratigraphy.