东海外陆架EA01孔末次冰期最盛期的三角洲沉积  

DELTAIC SEDIMENTARY SEQUENCES DEVELOPED DURING LAST GLACIAL MAXIMUM IN THE EA01 CORE ON THE OUTER SHELF OF THE EAST CHINA SEA

作　　者：李绍全[1] 李双林[1] 陈正新[1] 唐保根 陈裕迅 

机构地区：[1]青岛海洋地质研究所,青岛266071 [2]上海海洋石油局第一海洋地质调查大队,上海201208

出　　处：《海洋地质与第四纪地质》2002年第3期19-26,共8页Marine Geology & Quaternary Geology

基　　金：国家自然科学基金重点资助项目 (4 973 62 10 )

摘　　要：对东海 EA 0 1孔 (30°2 2 .96 15′ N、 12 5°4 5 .6 0 5 5′ E)岩心的沉积层序、粒度成分、沉积物年代、底栖有孔虫组合及其沉积环境的研究 ,揭示了东海外陆架末次冰期最盛期的三角洲沉积。钻孔 0 .36～ 2 9.6 5 m为一不完整的进积三角洲沉积层序 ,自下而上依次为前三角洲、河口沙坝和分流间湾的交替沉积 ;末次冰期三角洲的发育 ,表明了冰期低海面时期外陆架上的继承性沉降盆地仍被海水覆盖 ;盆地的区域沉降与海平面的共同作用形成了容纳沉积物的有效空间 ,捕获了河流带来的沉积物而形成三角洲 ,这是河流对海平面变化和构造下沉的响应 。The going into sea of rivers in China's Mainland during the Last Glacial Maximum is always a problem of public interest in marine geologic and Quaternary geologic circle,and mang geologists have inferred that they must have emptied into the Okinawa Trough.Up to now,however,the investigation results show that neither have sedimentary bodies resulting from the rivers into sea been found,nor have there been evident marks for water freshening phenomena in the last glacial sediments.The studies on the sedimentary sequences, grain size compositions, ages of sediments, assemblage of benthonic foraminifers and sedimentary environments revealed deltaic sedimentary sequences in the EA01 core (location: 30°22 9615′N, 125°45 6055′E) drilled in the outer shelf of the East China Sea. The deltaic sequences, from 0 36 m to 29 65 m, composed of prodelta (29 65~19 88 m), mouth bar (19 88~11 33 m), interdistributary bay (11 33~8 43 m) and mouth bar (8 43~0 36 m) again. The deltaic plain sequence is absent as a result of post glacial transgression and because the river mouth bar sedimentary sequence was covered with a thin layer of reworked 'relict sand '.The development of the delta during the Last Glacial Maximum suggests that the East China Sea basin in the outer shelf was in subsidence and below the sea level. The basin received the sediments transported by rivers from China's Mainland and formed the deltaic complex. The delta is rivers' response to sea level change and tectonic subsidence. It can be inferred that the large rivers from China's Mainland had poured into the basin during the period of Last Glacial Maximum.

关 键 词：东海 三角洲沉积 末次冰期 沉积层序 粒度成分 沉积环境 底栖有孔虫 

分 类 号：P736.21[天文地球—海洋地质]