Last glacial aeolian sequence at the Shidao Island of Xisha Islands and its cyclic features

The aeolian carbonate deposits cropped out at the Shidao Island of Xisha Islands are the product of the East Asian monsoon in last glacial stage. The dry and wet alternation of the East Asian monsoon has been recorded by the binary cycles of the deposits in the forms of dunes and paleosols. Using the drilling core of Xishi-2, combined with the detailed investigation of the geological sections at the Island, the aeolian sequence is re-divided into three layers of sand dune and two layers of palaeosol. Based on the dating data and the climatic changes in the East Asian monsoon, we believe that the vertical changes of the aeolian sequence or the alternation of dunes and paleosols correspond well with the second-order climatic sub-stages of L1 found at the Chinese Loess Plateau, indicating a cycle on precessional scale.