珠江三角洲地区全新世以来的沉积速率与沉积环境分析
- 中山大学近岸海洋科学与技术研究中心 广州 510275
- 收稿日期:
1900-01-01
- 修回日期:
1900-01-01
- 刊出日期:
2011-04-10
摘要: 为了探讨全新世以来珠江三角洲沉积演变的时空变化特征，将全新世珠江三角洲划分为4个阶段、12个区域，并根据92个钻孔，分别统计计算了不同阶段和区域的沉积速率。研究表明：（1）珠江三角洲在全新世4个阶段中的平均沉积速率有较大变幅，其中在10.0~7.5 ka BP最小，仅为1.27 mm/a，在7.5~5.0 ka BP阶段最大，为2.34 mm/a。这主要受沉积基底地形、海平面上升所引起的沉积空间的差异性所导致；（2）距今2 500年以来虽然由于人类活动频繁使珠江来沙量增多，但由于河湾中河道的形成、束窄，沉积物被输运到外海的比例不断增加，使得该时期平均沉积速率并不是全新世各期中最大；（3）由于三角洲复杂边界对河流和海洋动力的改造和重塑，高海面期三角洲的沉积中心同时分布在中部不同区域。表明三角洲的进积模式不同于其它大型三角洲——三角洲的发育并非单一自河口向外海逐渐发展，而是不同区域的沉积体同时多向发育。
Analysis on the Sedimentation Rates and Depositional Environment of the Pearl River Delta Area Since Holocene
- Center for Costal Ocean Science and Technology Research, Sun Yatsen University, Guangzhou 510275
- Received Date:
1900-01-01
- Rev Recd Date:
1900-01-01
- Publish Date:
2011-04-10
Abstract: To explore the spatial and temporal evolution of sedimentation in the Pearl River Delta Area (PRDA) since Holocene, the PRDA is divided into 12 subregions, and the evolution history is distinguished into 4 stages. Sedimentation rates of 92 cores were calculated for representing different subregions and evolution stages. The obtained sedimentation rates are 1.27 mm/a, 2.34 mm/a, 1.94 mm/a, 2.27 mm/a in 10.0~7.5 ka BP, 7.5~5.0 ka BP, 5.0~2.5 ka BP, 2.5~0 ka BP, respectively. Maximum rate occurred in 7.5~5.0 ka BP and minimum rate occurred in 10.0~7.5 ka BP. The depocenters were found to be located in the middle area, rather than only at the mouth of the paleoestuary bay, which is quite different from the normal pattern established in many estuaries. Maximum and minimum rates during different statges were caused by differences in sealevel rise and accommodation space; Since 2 500 a B P, human activities have increased the sediment amount discharged into the bay, but the dispersal to the offshore was also increased by the formation of river network and limitation of the accommodation space relative to the supply. Therefore the largest sedimentation rate was not situated then, contrary to the preexisting understanding. The existence of multiply depocenters in the paleoestuary bay indicated a new evolution pattern of the delta that several sand bodies progradated multidirectionally and simultaneously. This is much different from several largescale delta systems in the world that propagate seaward unidirectionally.
韦 惺. 珠江三角洲地区全新世以来的沉积速率与沉积环境分析[J]. 沉积学报, 2011, 29(2): 328-335.
| 引用本文: |
韦 惺. 珠江三角洲地区全新世以来的沉积速率与沉积环境分析[J]. 沉积学报, 2011, 29(2): 328-335.
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WEI Xing. Analysis on the Sedimentation Rates and Depositional Environment of the Pearl River Delta Area Since Holocene[J]. Acta Sedimentologica Sinica, 2011, 29(2): 328-335.
| Citation: |
WEI Xing. Analysis on the Sedimentation Rates and Depositional Environment of the Pearl River Delta Area Since Holocene[J]. Acta Sedimentologica Sinica, 2011, 29(2): 328-335.
|
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