| ZHANG Song,WANG Wei,HUANG Rihui,XU Liubing. 2015. The sedimentary source, planform stability and shore normal morphological change of the Xichong beach on the southern coast of the Dapeng Peninsula of Shenzhen, Guangdong Province, China. Acta Oceanologica Sinica, 34(3):76－89 |
| The sedimentary source, planform stability and shore normal morphological change of the Xichong beach on the southern coast of the Dapeng Peninsula of Shenzhen, Guangdong Province, China |
| 深圳大鹏半岛南岸西冲海滩的沉积物来源、平面形态稳定性及横向变化 |
| Received:February 22, 2014 Revised:August 05, 2014 |
| DOI：10.1007/s13131-015-0635-6 |
| Key words:headland bay beach sedimentary source beach stability beach seasonal change Dapeng Peninsula |
| 中文关键词: 岬湾海滩 沉积物来源 海滩稳定状态 海滩季节变化 大鹏半岛 |
| 基金项目: |
| Author Name | Affiliation | E-mail | | ZHANG Song | Shenzhen Dapeng Peninsula National Geopark Administration Office, Shenzhen 518121, China | | | WANG Wei | Geographic School, South China Normal University, Guangzhou 510631, China | wangw@scnu.edu.cn | | HUANG Rihui | Geographic School, South China Normal University, Guangzhou 510631, China | | | XU Liubing | Geographic School, South China Normal University, Guangzhou 510631, China | |
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| Abstract: |
| The coast of the Dapeng Peninsula has been honored as one of “the eight most beautiful coasts in China”. The most precious tourism resource for the peninsula is headland bay beaches, among which the beach at Xichong on the southern coast of the peninsula is the longest and the most important one. The information of the stability, sedimentary source and shape change of the beach is very important for maintaining the beach in terms of sustainable development of the peninsula. Heavy minerals in the sand of the beach and the inland stream at Xichong are compared with those of a nearby beach on the same coast to determine the beach sand source; with help of a computer software, MEPBAY, the equilibrium planforms of the beaches on the peninsula are compared with those of an island without rivers to evaluate the stream's effects on the beach stability; cross shore profiles along the Xichong beach are also surveyed in different seasons of a year to assess the annual shore normal beach changes affected by the stream input, and the relation between the equilibrium planform state and cross shore changes of the beach. It is shown that (1) stream is the main sedimentary source of the beach and the weathering materials of the rocky headlands on both sides of the bay transported by waves are the second source for the beach but it is limited, sand from an inner shelf is not the sedimentary source for the beach at present and was not even during the Holocene transgression; (2) the Xichong beach cannot reach static equilibrium around the entire bay shoreline, the segment of the shoreline where a stream outlet is located is in dynamic equilibrium, and the unstable section occurs in the wave shadow region in the lee of an offshore island; (3) no matter whether the section of the beach shoreline at Xichong is in an equilibrium state or not, it is eroded in the typhoon season and recovered after the season, the maximum change in erosion and accretion occurs in the unstable segment; (4) the Xichong beach can only have small sand body since it is supplied with sand mainly form inland streams, resulting in a possible danger in which sand loss induced by human activities or huge storms cannot be replenished naturally. |
| 中文摘要: |
| 深圳大鹏半岛海岸被誉为中国最美的八大海岸之一,岬湾海滩是大鹏半岛最珍贵的旅游资源,其中位于半岛南岸的西冲海滩是其最长,也是最重要的岬湾海滩。西冲海滩的沉积物来源、平面形态稳定性及横向变化特征是维护半岛海岸环境可持续发展的重要信息。本文利用西冲及附近海滩的海滩砂和输入河流沉积物中的重矿物对比,分析西冲海滩的沉积物来源;利用计算机软件MEPBAY对比半岛有河流输入海滩和无河流海岛海滩的平面形态,分析河流输入对海滩平面均衡状态的影响;通过不同季节多个海滩横向剖面对比,分析海滩横向变化与平面均衡状态的关系以及河流输入对海滩横向变化的影响。上述分析表明:1)河流沉积物输入是海滩的主要沉积物来源,海滩两侧岬角被波浪冲刷带来的物质也是其沉积物来源之一,但数量有限。海湾以外大陆架沉积物既不是海滩的现代沉积物来源,也不是全新世海侵时海滩的沉积物来源;2)西冲海滩不能在整个海滩岸线上都达到静态平衡,在有河口的岸段处于动态平衡,在有岛屿遮蔽的岸段处于不稳定状态;3)无论海滩岸线是否处在平衡状态之中,岸线都要在台风季节被侵蚀,其后恢复,其中不稳定岸段变化最大;4)由于仅由河流提供沉积物,西冲海滩体积有限,人工挖沙或大风暴造成的泥沙流失很可能无法自然恢复。 |
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