| 珠江口外海域与珠江三角洲晚更新世以来的地层层序对比 |
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| 引用本文： | 韦成龙,张珂,余章馨,邱燕.珠江口外海域与珠江三角洲晚更新世以来的地层层序对比[J].沉积学报,2015,33(4):713-723. |
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| 作者姓名： | 韦成龙 张珂 余章馨 邱燕 |
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| 作者单位： | 1.国土资源部海底矿产资源重点实验室 广州海洋地质调查局 广州 510075; |
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| 基金项目： | 广东省自然科学基金，国家地勘专项项目 |
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| 摘 要： | 本文综合运用珠江三角洲外南海北部陆架的地震测线和三角洲地区的钻孔资料进行联合解译,获得由浅海至陆地的层序地层剖面,辨识出三角洲地区4套地层层序和南海北部陆架6套地层层序及体系域,前者仅记录了2个沉积旋回和相应的2次海面变化,而后者记录了更多沉积旋回及相应的海平面波动.在海、陆层序对接和对比的基础上,文章重点把南海北部陆架6套地层层序与深海氧同位素阶段MIS6~MIS1进行了对比分析,认为珠江三角洲下旋回与南海北部陆架层序D相当,珠江三角洲下旋回对应着南海北部陆架MIS6~MIS5(距今15万年~8万年)时代的层序地层,MIS4~MIS2末次冰期低海面时期的三角洲沉积位于现今南海北部陆架之上,并未向北延伸到现代珠江三角洲地区.珠江三角洲和南海北部陆架的下沉都是南海陆缘扩张的表现.
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| 关 键 词： | 珠江口外海域 单道地震剖面 层序地层 海平面变化 |
| 收稿时间： | 2014-06-23 |
Correlation of Stratigraphic Sequences between the Pearl River Delta and Its Offshore Continental Shelf since the Late Pleistocene |
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| Institution: | 1.MLR Key Laboratory of Marine Mineral Resources, Guangzhou Marine Geological Survey, Guangzhou 510075;2.Department of Geosciences, Sun Yat-Sen University, Guangzhou 510275;3.Guangdong Key Laboratory of Geological Process and Mineral Resources Exploration, Guangzhou 510275 |
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| Abstract: | Applying concepts of sequence stratigraphy to the interpretation of high resolution seismic profiles on the northern continental shelf of the South China Sea, and to borehole records of the modern Pearl River Delta, north of the continental shelf, permit the recognition of the stratigraphy evolution model during the past ca. 200 kyr. Previous research on the Pearl River Delta indicates that the delta has two marine transgression cycles. Although there has been consensus on the age of the 2nd cycle, which resulted from a postglacial sea level rise, the age of the 1st cycle is greatly debated. Based on 14C and TL dating (40~50 ka B.P.), the 1st cycle was regarded as deposits during MIS3. But the sea level of MIS3 was about 50 m lower than present, and the altitudes of the marine deposits of the 1st cycle, i.e. -25~-1+0 m, in the delta do not match with the sea level of MIS3. Correlation of the sedimentary sequence between the Pearl River Delta and its offshore continental shelf provides a reconsideration of this problem. Four sets of delta formation, six sets of sequence stratigraphy and system tracts of each sequence on the continental shelf are identified. Sequence C, which indicates the transgression during MIS3, did not extend northwards to modern delta area, where only fluvial sediments and weathered deposits are found during the MIS4-MIS3 marine transgression and the MIS3-MIS2 regression. While the HST of sequence D, which indicates the high sea level during MIS5e, can be correlated with the 1st cycle in the Pearl River Delta. The last transgression cycle, represented by sequence B, A, and the upper cycle of the modern Pearl River Delta, indicates the rapid sea level rise after the Last Glacial Maximum to the early Holocene, and the highstand progradation during the last 6 000 yrs. The delta-continental shelf environmental transition was controlled by both global sea level change and regional neotectonic subsidence related to divergent continental margin of South China Sea. |
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| Keywords: | Pearl River Delta single-channel seismic profile sequence stratigraphy sea level change |
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