| The sediment provenances were discussed in this paper on the basis of grain-size,clay mineral, rare earth element, major element, heavy mineral and AMS14 C dating analysis that were carried out for core X2, which was retrieved from the continental shelf of the Hainan Island in the South C hina Sea(SCS). Results show that core X2 can be divided into two stages, stage I and stage II. Compared with stage I(240~120 cm, 7.6~4.0 ka BP), sediment mean grain size in stage Ⅱ(120~0 cm, 4.0~0 ka BP) becomes coarser, the stage I is mainly composed of clay silt while the stage Ⅱ consists mainly of silty sand, the content of major elements decrease(Al2O3, TFe2O3, K2 O, MgO, Na2 O, TiO2, CaO, P2O5, MnO), the content of illite and chlorite decrease while the kaolinite increased, and the rare earth element characteristic parameters change fluctuation. the heavy mineral mainly consist of Pyrite, ilmenite and limonite in stageⅠ, while mainly consist of Magnetite, ilmenite and zircon in stage Ⅱ. Research on provenances indicate that the sediments of core X2 were mainly derived from Hainan Island and Taiwan, and small amount from the Pearl River. The sediments in stage I were dominantly from Hainan Island and Taiwan. In stage Ⅱ the sediments were mainly from Hainan Island, which may be influenced by the Pearl River materials.The results suggest that the contribution of world-class rivers(such as the Pearl River) to continental shelf of the northern South China Sea may be overestimated, while the influence of small rivers(such as Taiwan, Hainan Island, etc) may be underestimated in the previous researches. Therefore, more attention should be paid to the contribution of small rivers in the future studies of the continental shelf. The coarsening of the sediment and the great change of all the index means that the provenance or the lithology of core X2 changed,which may result from climatic variation and enhancement from human activities since 4000 a BP. |
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