A coupled approach based on grain size and geochemical elements is used to trace the provenance of surface sediments and to confirm the distribution patterns of grain size and elements on the continental shelf off wes...A coupled approach based on grain size and geochemical elements is used to trace the provenance of surface sediments and to confirm the distribution patterns of grain size and elements on the continental shelf off western Guangdong Province and northeastern Hainan Island. The mean grain size ranges from 0.05 φ to 7.28 φ with a mean value of 5.60 φ. The average concentra- tions of major elements descend in the order of SiO2 > Al2O3 > CaO > Fe2O3 > K2O > MgO > Na2O > TiO2 > P2O5 > MnO, while those of trace elements exhibit a descending order of Sr > Rb > Zn > V > Cr > Pb > Ni > Cu > As > Cd. On the basis of the distribution patterns of elements and results of statistical analysis, the study area is classified into three zones. Zone I locates on the continental shelf off western Guangdong Province, and the sediments are mainly from Pearl River, Taiwan Residents rivers, and small rivers nearby. Zone II locates in the eastern exit of Qiongzhou Strait and the coastal area off Leizhou Peninsula, and the sediments are mainly from the ero- sion products of Qiongzhou Strait and Hainan Island. Zone III locates off the eastern Hainan Island and the continental shelf deeper than 50 m isobaths, and the sediments are mainly from Hainan Island and coral reef. The influence from open water should also be considered. Results indicate that the grain size is the main controlling factor for major and trace element contents and that anthropo- genic impact and biological activity also play an important role in the distribution of these elements.展开更多
八所组是琼东北晚第四纪一个重要地层单位,同时也是河流Ⅱ级阶地(T2)的主要沉积地层,其形成年代对该区域晚第四纪以来的古环境演化及地壳运动的研究有着重要意义。为了限定其形成时代,文章采取ESR的方法,对广泛分布于琼东北珠溪河及古...八所组是琼东北晚第四纪一个重要地层单位,同时也是河流Ⅱ级阶地(T2)的主要沉积地层,其形成年代对该区域晚第四纪以来的古环境演化及地壳运动的研究有着重要意义。为了限定其形成时代,文章采取ESR的方法,对广泛分布于琼东北珠溪河及古三江河一带的八所组地层进行了系统的测年。结果表明:该套地层形成于晚更新世中晚期(64.36 ka～18.40 ka BP);沉积时代对应末次冰期MIS4～MIS2阶段;河流的下切与T2阶地的形成,一定程度上反映了该时期琼东北海平面的频繁波动及地壳的间歇性抬升;此外,分布于现代海岸风沙强烈作用地带的老红砂与八所组属同期异相的风成堆积,应与八所组地层加以区分。展开更多
基金supported by the National Natural Science Foundation of China (Nos. 41476047, 41106045, 41506064 and 41427803)the National Programme on Global Change and Air-Sea Interaction (Nos. GASIGEOGE-03 and GASI-04-01-02)
文摘A coupled approach based on grain size and geochemical elements is used to trace the provenance of surface sediments and to confirm the distribution patterns of grain size and elements on the continental shelf off western Guangdong Province and northeastern Hainan Island. The mean grain size ranges from 0.05 φ to 7.28 φ with a mean value of 5.60 φ. The average concentra- tions of major elements descend in the order of SiO2 > Al2O3 > CaO > Fe2O3 > K2O > MgO > Na2O > TiO2 > P2O5 > MnO, while those of trace elements exhibit a descending order of Sr > Rb > Zn > V > Cr > Pb > Ni > Cu > As > Cd. On the basis of the distribution patterns of elements and results of statistical analysis, the study area is classified into three zones. Zone I locates on the continental shelf off western Guangdong Province, and the sediments are mainly from Pearl River, Taiwan Residents rivers, and small rivers nearby. Zone II locates in the eastern exit of Qiongzhou Strait and the coastal area off Leizhou Peninsula, and the sediments are mainly from the ero- sion products of Qiongzhou Strait and Hainan Island. Zone III locates off the eastern Hainan Island and the continental shelf deeper than 50 m isobaths, and the sediments are mainly from Hainan Island and coral reef. The influence from open water should also be considered. Results indicate that the grain size is the main controlling factor for major and trace element contents and that anthropo- genic impact and biological activity also play an important role in the distribution of these elements.
文摘八所组是琼东北晚第四纪一个重要地层单位,同时也是河流Ⅱ级阶地(T2)的主要沉积地层,其形成年代对该区域晚第四纪以来的古环境演化及地壳运动的研究有着重要意义。为了限定其形成时代,文章采取ESR的方法,对广泛分布于琼东北珠溪河及古三江河一带的八所组地层进行了系统的测年。结果表明:该套地层形成于晚更新世中晚期(64.36 ka～18.40 ka BP);沉积时代对应末次冰期MIS4～MIS2阶段;河流的下切与T2阶地的形成,一定程度上反映了该时期琼东北海平面的频繁波动及地壳的间歇性抬升;此外,分布于现代海岸风沙强烈作用地带的老红砂与八所组属同期异相的风成堆积,应与八所组地层加以区分。
