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
On October 12th,2019,a MS5.2 earthquake occurred in Beiliu City,Guangxi Zhuang Autonomous Region,China,with a focal depth of 10 km. The epicenter is located in the junction of Guangxi and Guangdong where the moderate-...On October 12th,2019,a MS5.2 earthquake occurred in Beiliu City,Guangxi Zhuang Autonomous Region,China,with a focal depth of 10 km. The epicenter is located in the junction of Guangxi and Guangdong where the moderate-strong earthquakes are relatively active. The highest intensity of this earthquake is estimated up to Ⅵ besides the isoseismic line showed an ellipse shape with a long axis trend in the NW direction.The aftershocks are not evenly distributed. The parameters of the focal mechanism solutions are: strike 346°,dip 85°,rake 19° for the nodal planeⅠ,and strike 254°,dip 71°,rake 175° for the nodal planeⅡ. The type of the coseismic fault is strikeslip. After analyzing these results above and the active faults near the epicenter,we get that the nodal planeⅠ is interpreted as the coseismic rupture plane and the BamaBobai Fault is a seismogenic structure of MS5.2 Beiliu earthquake.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.
基金sponsored by the National Natural Science Foundation Guangdong Union Foundation(U1901602)。
文摘On October 12th,2019,a MS5.2 earthquake occurred in Beiliu City,Guangxi Zhuang Autonomous Region,China,with a focal depth of 10 km. The epicenter is located in the junction of Guangxi and Guangdong where the moderate-strong earthquakes are relatively active. The highest intensity of this earthquake is estimated up to Ⅵ besides the isoseismic line showed an ellipse shape with a long axis trend in the NW direction.The aftershocks are not evenly distributed. The parameters of the focal mechanism solutions are: strike 346°,dip 85°,rake 19° for the nodal planeⅠ,and strike 254°,dip 71°,rake 175° for the nodal planeⅡ. The type of the coseismic fault is strikeslip. After analyzing these results above and the active faults near the epicenter,we get that the nodal planeⅠ is interpreted as the coseismic rupture plane and the BamaBobai Fault is a seismogenic structure of MS5.2 Beiliu earthquake.
