中全新世以来南海琼东南近岸泥质区物质来源  

Sediment provenance of offshore mud area of the eastern Hainan Island in South China Sea since the Mid-Holocene

作　　者：闫慧梅 田旭 徐方建[1] 胡邦琦[3] 杨耀民 冯建伟[1] 李安春[4] 郭晨[5] 刘兆庆 

机构地区：[1]中国石油大学(华东)地球科学与技术学院,山东青岛266580 [2]国家深海基地管理中心,山东青岛266237 [3]国土资源部海洋油气资源和环境地质重点实验室,山东青岛266071 [4]中国科学院海洋研究所海洋地质与环境重点实验室,山东青岛266071 [5]西安科技大学地质与环境学院,陕西西安710000

出　　处：《海洋学报》2016年第7期97-106,共10页

基　　金：国家自然科学基金(41430965;41106040;41576058);国家科技重大专项(2016ZX05047-003;2011ZX05009-002);中央高校基本科研业务费专项资金(12CX02003A);青岛市基础研究计划项目(13-1-4-197-jch)

摘　　要：对位于南海琼东南近岸泥质区的X2站柱状沉积物进行了粒度、Sr-Nd同位素、常量元素(Al_2O_3、TFe_2O_3、K_2O、MgO、Na_2O、TiO_2、CaO、P_2O_5、MnO)和AMS14 C年代分析,探讨了中全新世以来该沉积区的物质来源。结果表明,X2站沉积物可划分为上(A2段,120~0cm,4.0~0ka BP)、下(A1段,240~120cm,7.6~4.0ka BP)两个沉积地层单元,A2段较A1段沉积物平均粒径变粗,已测的9种常量元素含量减少。^(87)Sr/^(86)Sr与εNd除异常点外,总体变化幅度不大。X2站沉积物主要来源于海南岛和台湾,珠江贡献较小,其中A1段沉积物主要是海南岛和台湾岛来源物质的混合,A2段沉积物主要来源于海南岛,其次珠江物质可能也有影响。据X2站研究结果初步表明,世界级大河(如珠江)对南海北部陆架区(特别是琼东南近岸泥质区)的贡献以前可能被高估,而山溪型河流(如台湾岛、海南岛等河流)的贡献却可能被低估,日后研究中应该重视小型河流对陆架区的物质贡献。The sediment provenances were discussed in this paper based on grain-size, Sr--Nd isotopes, major ele- ment （Al2O3, TFeeO3, K2O, MgO, Na20, TiO2, CaO, P2O5, and MnO） and AMS14C dating for core X2, which was retrieved from the offshore mud area of the eastern Hainan Island in the South China Sea （SCS）. Re- suits showed that core X2 can be divided into two sedimentary strata units （unit A1 and unit A2）. Compared with unit A1 （240--120 cm, 7. 6--4.0 ka BP）, sediment mean grain size in unit A2 （120--0 cm, 4.0--0 ka BP） be- came coarser and the content of major elements decreased. In addition to the abnormal value, the trends of SrSr/ 86 Sr and cxa in core X2 were relatively stable. The sediments of core X2 were mainly derived from Hainan and Tai- wan islands, and partly Pearl River. The sediments in unit A1 were primarily a mixture of Hainan and Taiwan islands. In unit A2, the sediments were mainly from Hainan Island, and partly Pearl River. The results suggested that the contribution of world-class river （i. e. , the Pearl River） to the continental shelf of the northern SCS may be overestimated, while the influence of small rivers （i. e. , Taiwan and Hainan islands） may be underestimated in the previous studies. Therefore, more attention should be paid to the contribution of small rivers to the continental shelf area in the future studies.

关 键 词：南海 陆架 全新世 粒度 常量元素 SR-ND同位素 物质来源 

分 类 号：P736.212[天文地球—海洋地质]