| 从沉积速率和沉积物粒度看冰后期海侵以来珠江三角洲西江大鳌沙的形成 |
| |
| 引用本文： | 何志刚,莫文渊,刘春莲,吴超羽.从沉积速率和沉积物粒度看冰后期海侵以来珠江三角洲西江大鳌沙的形成[J].古地理学报,2007,9(3):331-336. |
| |
| 作者姓名： | 何志刚 莫文渊 刘春莲 吴超羽 |
| |
| 作者单位： | 1.中山大学海洋科学与技术研究中心 广东广州510275;2.中山大学地球科学系 广东广州510275 |
| |
| 基金项目： | 国家自然科学基金
,
国家自然科学基金
,
广东省自然科学基金 |
| |
| 摘 要： | 大鳌沙处于珠江三角洲西江河口的近口段，洪季西江河口的潮区界西线在其顶端附近。冰后期海侵以来，大鳌沙顶端的PRD05和中部的PRD04两个钻孔的沉积速率和沉积物粒度有着极大的差别。7 630 a BP以前，PRD04孔的沉积速率小于PRD05孔的沉积速率；但7 630 a BP以来，PRD04孔的沉积速率大于PRD05孔的沉积速率。从粒度分析看，埋深12.28 m以下，PRD04孔沉积物比PRD05孔的粗，分选性比PRD05孔的差；埋深12.28 m以上，PRD04孔的沉积物比PRD05孔的细，分选性相对比PRD05孔的好。分析表明，9 000～4 200a BP， 沉积物由南（中部）向北（顶部）输运，涨潮流冲蚀老沉积物，在喷出磨刀门通道后，流速迅速降低，粗颗粒泥沙先沉积，而细颗粒泥沙被涨潮流搬运至更北的区域沉积。近3500年以来，河流动力占优势，沉积物由北（顶部）向南（中部）输运。大鳌沙的形成与涨潮射流密切相关。涨潮射流口的位置在蛇地山和右岸纵向山地之间，宽约2200 m。
|
| 关 键 词： | 珠江三角洲 大鳌沙 冰后期海侵 沉积速率 沉积物粒度 涨潮射流 |
| 文章编号： | 1671-1505（2007）03-0331-06 |
| 修稿时间： | 2006-09-252006-11-06 |
Formation of Xijiang Da'aosha in Pearl River Delta during the postglacial period from a perspective of sedimentation rates and sediment grain size |
| |
| He Zhigang,Mo Wenyuan,Liu Chunlian,Wu Chaoyu.Formation of Xijiang Da''''aosha in Pearl River Delta during the postglacial period from a perspective of sedimentation rates and sediment grain size[J].Journal of Palaeogeography,2007,9(3):331-336. |
| |
| Authors: | He Zhigang Mo Wenyuan Liu Chunlian Wu Chaoyu |
| |
| Institution: | 1.Center for Coastal Ocean Science and Technology Research, Sun Yat sen University, Guangzhou510275, Guangdong;2.Department of Earth Sciences, Sun Yat sen University, Guangzhou510275, Guangdong |
| |
| Abstract: | The Da'aosha is located in the near-mouth section of the Xijiang estuarine of the Pearl River Delta. The boundary of tidal influence during flood season is near the top of the Da'aosha. Two boreholes (PRD04 and PRD05) were drilled in the proximal and central parts of the Da'aosha respectively. The core records show that the sedimentation rates and sediment grain size are quite different between PRD04 and PRD05 since the postglacial period. PRD04 exhibits lower sedimentation rates than PRD05 prior to 7,630 a,BP, but hihger since 7 630 a BP. The sediments in PRD04 are poorly-sorted, and the sediment grain size is coarser when the burial depth is below 12.28 m, but the sediments become finer and well-sorted above 12.28 m compared with PRD05. Analyses indicate that the sediments were transported by flood currents from south to north during 9 000~4 200 a BP. The flood currents eroded the previously deposited sediments. With a marked decrease in current velocity after the flood currents passed through the Modaomen channel, the coarse-grained muds and sands accumulated first, while the fine-grained sediments were transported further towards the north. Since 3 500 a BP, the sediments in the north became coarser than those in the south, suggesting that the sediments were transported from the north to the south due to the change to river dominance. The formation of the Da'aosha was closely related to the flood jet. The flood jet inlet, with a width about 2 200 m, was situated between the Shedi Hill and the hills along the right bank of the Xijiang River. |
| |
| Keywords: | Pearl River Delta Da'aosha postglacial transgression sedimentation rate sediment grain size flood jet |
| 本文献已被 CNKI 维普 万方数据 等数据库收录！ |
| 点击此处可从《古地理学报》浏览原始摘要信息 |
| 点击此处可从《古地理学报》下载免费的PDF全文 |
