Characteristics of volcanic ash in surficial sediments around Zhongsha islands(Macclesfield Bank):response to extensional tectonic setting in the northern margin of the South China Sea
Volcanic ash in surficial sediments around Zhongsha Islands,the South China Sea,mainly include three kinds of volcanogenic detritus,for example,brown volcanic glass,colorless volcanic glass and volcanic scoriaTAS diagram for these three kinds of volcanogenic detritus mentioned above,combined with variation diagram for Al2O3 FeO*、MgO、CaO Na2O、K2O vs SiO2,shows that there may be exist birnodal volcanic activity in the northern margin of the South China Sea,brown volcanic glass and colorless volcanic glass represent basic end member and acidic end member respectively,and crystallization differentiation is the main process for magma evolution.The bimodal volcanic activity implies that the origin of volcanic activity lies in continental extensional setting,supports that Xisha trench is a phenomena for ongoing or activating extensional geodynamics setting,and affirms that there exists Hainan plume which is put forward based on geophysical data.
brown volcanic glass colorless volcanic glass bimodal volcanic activity extensional setting the northern margin of the South China Sea
Yan Quan-Shu Shi Xue-Fa Liu ji-hua
Key laboratary of Marine Sedimentology and Environment Geology,State Oceanic Administration,Qingdao 266061,China
国内会议
青岛
英文
97-107
2007-08-01（万方平台首次上网日期，不代表论文的发表时间）