The giant gas area in western South China Sea includes the Yinggehai Basin and Qiongdongnan Basin as well as the Zhusan Depression in the west of Zhujiangkou Basin,being a rapidly subsiding Cenozoic sedimentary basin.

• 南海西部大气区包括莺歌海盆地、琼东南盆地和珠江口盆地西部的珠三坳陷，是一个快速沉降的新生界沉积盆地。