摘要
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。
Seismic reflection survey for the South Okinawa Trough shows that (1)The overlying formation in the South Okinawa Trough is composed of seismic sequences Ⅰ and Ⅱ, with the ages of Quaternary and Pliocene respectively There may be Miocene series in parts of the trough bottom The sediments in the northwest section of the trough bottom, where the turbidites are well developed, are thicker than those in the southeast section, which shows that the sediments are mainly from the mainland of China The thickness of seismic sequences along the axis of the trough is much larger than that of both sides, which suggests that the trough is still in the process of rifting; (2)There are two groups of faults well developed in the trough, one is NE\|SW (E\|W at the southwestend) which is tensional and tension\|torsional faults The other, usually cutting the former, is tensional strike\|slip faults in NW-SE direction; (3)Magmation is rather strong and it is infered that basic and neutral rock is dominant.
出处
《东海海洋》
2001年第1期19-26,共8页
Donghai Marine Science
基金
国家重点基础研究发展规划项目资助! (G2 0 0 0 0 4 67)
