全新世中国大河三角洲沉积演化模式转化及其对人类活动的响应

Changes of evolution models of China's large river deltas since Holocene and their responses to anthropogenic activities

  • 摘要: 中国三大河口三角洲包括黄河三角洲、长江三角洲和珠江三角洲,在国民经济发展和全球海陆相互作用研究中均扮演着非常重要的角色。因此,全面揭示河口三角洲演化进程,总结河口三角洲演化模式,对指导河口三角洲可持续开发利用具有重要意义。本文结合前人研究进展及近年来海洋区域地质调查资料,系统总结了全新世以来我国三大河口三角洲“三个阶段,三个尺度,各具特色”的演化模式,揭示了全新世初期、两千年前和工业革命后三个阶段千年-百年-年代际时间尺度下河口三角洲演变模式转化的主控因素,认为河口三角洲的演化模式正在由自然演变向人为控制转型,人类活动正剧烈地影响着河口三角洲的自然演化进程。三大河口三角洲沉积演化模式各具特色,黄河三角洲具有超级叶瓣与叶瓣发育演替特色,长江三角洲具有北岸沙岛并岸、南岸不断推展特色,珠江三角洲则表现为河网发育充填、逐级分汊延伸特色。随着河口三角洲演化受人类活动影响的加剧,正确认识河口三角洲演化规律及其主控因素,不仅有助于提升三角洲地区陆海相互作用研究水平,而且将为三角洲可持续开发利用提供科学依据。

     

    Abstract: As a key component of the global environmental system, deltas are located in the specific areas suffering strong land-sea interaction. Generally, the deltaic regions are rich in natural resources, densely populated, highly urbanized and active in human activities, but they are fragile in terms of ecological conditions. The China’s large deltas, i.e the Yellow River Delta, the Yangtze River Delta and the Pearl River Deltas, have played important roles in the economic development of the country and contributed much to global environmental changes. Therefore, it is significant to reveal the deltas’ evolution processes and depositional models to ensure the sustainable development of the deltas and utilization of their resources. In this paper, we summarized synthetically the evolutionary models of these deltas based on the data from regional marine geological surveys and their precious results. Since Holocene, the evolution of China’s large river deltas has suffered three stages of evolution in three time-scales with their exclusive features. By these models, the factors influencing the delta evolution are discussed on millennium, centennial, interannual time scales respectively. The evolutionary models have changed from the natural factor dominated to human factor dominated owing to the stronger anthropogenic activities. It is an urgent need to strengthen the study of estuary delta evolution under the influence of human activities, so as to provide more scientific support for the sustainable development and full use of deltaic resources in these regions.

     

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