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 t...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.展开更多
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)
文摘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.
