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对南冲绳海槽进行反射地震调查 ,结果表明 :(1 )海槽盖层主要由反射层组 (时代相当于第四纪 )和反射层组 (时代相当于上新世 )组成 ,推测槽底局部存在中新统。槽底沉积物主要源自中国大陆。轴部目前仍处在裂陷作用阶段 ;(2 )断裂极为发育 ,可分 NE— SW向(西南端转为近 E— W向 )和 NW— SE向两组 ,分别属张性及张扭性断裂 ,后者切割前者 ;(3)岩浆活动十分强烈 ,东南缘岩浆活动尤甚 ,推测其岩性以中、基性岩为主
Reflecting the seismic survey of the South Okinawa Trough, the results show that: (1) The trough caprock mainly consists of a reflection layer (equivalent to the Quaternary period) and a reflection layer (the age corresponds to the Pliocene) Miocene exists locally. Sink sediments mainly from mainland China. The shaft is still in the stage of rifting; (2) The fracture is extremely developed, which can be divided into two groups: NE-SW direction (near EW direction) and NW-SE direction The latter cutting the former; (3) the magmatic activity is very strong and the magmatic activity in the southeast margin is even more serious, suggesting that the lithology is mainly medium and basic rocks