^(40)Ar/^(39)Ar ages of seamount trachytes from the South China Sea and implications for the evolution of the northwestern sub-basin  

作　　者：Xiaohu Li Jiabiao Li Xing Yu Chunsheng Wang Fred Jourdan 

机构地区：[1]Key Laboratory of Submarine Geoscience, State Oceanic Administration [2]Second Institution of Oceanography, State Oceanic Administration [3]Key Laboratory of Marine Ecosystem and Biogeochemistry, State Oceanic Administration [4]Western Australian Argon Isotope Facility, Department of Applied Geology and Jd L Centre, Curtin University

出　　处：《Geoscience Frontiers》2015年第4期571-577,共7页地学前缘（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grant Nos.91028006 and 41276055);the National Basic Research and Development Program(Grant Nos.2007CB411700,2013CB429700);China Ocean Mineral R&D Association(COMRA)project(DY125-12-R-02,04,06)

摘　　要：A chronological study of seamount rocks in the South China Sea basin provides a great opportunity to understand the expansion and evolution history of the sea basin. In this paper, we analyzed the ^40Ar/^39Ar age of trachytic samples collected from the Shuangfeng seamounts in the northwestern sub-basin of the South China Sea. The two samples yielded plateau ages of 23.80 ± 0.18 and 23.29 ± 0.22 Ma, respectively, which indicate magmatic activity in late Oligocene which helpful constraints the expansion time of the northwest sub-basin. Previous studies suggested that the northwestern sub-basin and southwestern sub-basin have experienced a relatively consistent expansion in the NW-SE direction followed by a late expansion of the eastern sub-basin. We concluded that the expansion of the northwestern sub-basin began prior to ca. 24 Ma, which also implicated magmatic events of a late or stop expansion of the northwestern sub-basin combined with our results of^40Ar/^39Ar age data and previous geophysical data.A chronological study of seamount rocks in the South China Sea basin provides a great opportunity to understand the expansion and evolution history of the sea basin. In this paper, we analyzed the ^40Ar/^39Ar age of trachytic samples collected from the Shuangfeng seamounts in the northwestern sub-basin of the South China Sea. The two samples yielded plateau ages of 23.80 ± 0.18 and 23.29 ± 0.22 Ma, respectively, which indicate magmatic activity in late Oligocene which helpful constraints the expansion time of the northwest sub-basin. Previous studies suggested that the northwestern sub-basin and southwestern sub-basin have experienced a relatively consistent expansion in the NW-SE direction followed by a late expansion of the eastern sub-basin. We concluded that the expansion of the northwestern sub-basin began prior to ca. 24 Ma, which also implicated magmatic events of a late or stop expansion of the northwestern sub-basin combined with our results of^40Ar/^39Ar age data and previous geophysical data.

关 键 词：^40Ar/^39Ar datingSeamount trachyteNorthwest sub-basinExpansion historySouth China Sea 

分 类 号：P736.1[天文地球—海洋地质] Q959.12[天文地球—海洋科学]