Sediment provenance and paleoenvironmental evolution in southeastern shelf of Hainan Island since Holocene

Abstract

AMS14C dating, particle size and clay mineral analysis were carried out on the QZ4 core from the southeastern shelf of Hainan Island in this study. The material source and sedimentary environment evolution of the southeastern shelf of Hainan Island were discussed. Analysis of clay minerals shows that the terrigenous clasts of the southeastern shelf of Hainan Island are mainly from Hainan Island. The particle size endmember simulation identifies two endmembers. The EM1 endmember corresponds to the mixed deposition of near-source and far-source fine materials transported by Marine current systems, while EM2 mainly corresponds to coarse-grained materials imported from the near-source rivers of Hainan Island. The two endmembers represent two different transport mechanisms. The sedimentary environment in the study area can be roughly divided into three stages: 11.2-9.2 ka BP, 9.2-6.6 ka BP and 6.6 ka BP to date correspond to foreshore, near-shore and shallow Marine shelf sedimentary environments respectively. During 11.2-6.6 ka BP period, the sedimentary environment was mainly controlled by sea level changes, but extreme cold events such as "9.4 ka BP cold event" and "8.2 ka BP cold event" still had an important impact on the southeastern shelf of Hainan Island. Up to 6.6 ka BP, the sedimentary record is mainly controlled by climate change, and the increase of fluvial contribution and chemical weathering may be due to the intensification or number of typhoons. It is urgent to carry out follow-up research on high-resolution typhoons and storms in sediments in the eastern shelf area and adjacent areas of Hainan Island.