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对琼州海峡及周边海域约600个表层样品进行粒度分析后发现,琼州海峡内沉积物以粗粒的含砾砂及砂为主,自海峡内向口外则由砂向粉砂过渡,最外侧分布有更细粒的粘土质粉砂,东口砂质沉积物边缘以弧形分布为主,西口呈指状分布.按峰态类型可将粒度频率曲线分布划分为海峡东单峰态、海峡东双峰态、海峡内单双峰态、海峡西单峰态及海峡西双峰态5个区域.采用GSTA模型对沉积物运移趋势分析后发现,沉积物在海峡内主要由南北两侧向中间运移,海峡东口沉积物具有比较明显的由口内向口外输运的趋势,海峡西部沉积物出海峡口后显示了向北输运的趋势,沉积物粒度特征分布及运移趋势说明海峡内及两侧三角洲内沉积物主要来自于海峡底部及南北两岸的潮流冲刷物.根据琼州海峡现代沉积环境,结合周边4个柱状沉积物粒度及14 C测年分析,发现琼州海峡的最终形成大约开始在距今8 000a前,由于海平面的上升,潮流作用塑造了海峡初期的地貌,直到距今约5 000~4 600a前,琼州海峡一直处于快速发展阶段,潮流三角洲发育也最广,之后由于暖期的结束,海平面下降,随着潮流作用的减弱,琼州海峡趋于稳定状态,逐渐形成今天的海峡及口外水下三角洲地貌.
After analyzing the grain size of about 600 surface samples from the Qiongzhou Strait and the surrounding sea areas, it is found that the sediments in the Qiongzhou Strait mainly consist of coarse-grained gravelly sand and sand, from sand to silt from the inside of the channel to the mouth, and the outermost distribution Finer granular clayey silt, the eastern edge of sandy sediments arc-shaped distribution, the western mouth was finger-like distribution.According to the kurtosis type can be divided into the particle size frequency distribution of the East Channel Strait, East Shuangfeng Stratigraphy, monsoon-doublet state within the strait, Xidian krait strait, and west bifurcation state in the strait.5 Using the GSTA model to analyze the trend of sediment transport, it was found that the sediment mainly migrated to the middle of both sides of the strait within the strait , The sediments in the east of the Strait have obvious tendency of exporting from the mouth to the outside of the mouth. The trend of the northward transport of the sediments in the west of the Strait shows the trend of sediment distribution and migration. Sediments in the delta mainly come from tidal currents at the bottom of the channel and between the north and souths.According to the modern depositional environment in the Qiongzhou Strait and the analysis of the grain size of the four columnar sediments and the 14 C dating, it is found that the final shape of the Qiongzhou Strait About 8,000 years ago, the Qiongzhou Strait has been in rapid development until about 5000 ~ 4 600 years ago because of the sea level rise and the tidal current shaping the initial Strait morphology. The trend delta has the most extensive development, Afterwards, due to the end of warm period, the sea level dropped. As the tide effect became weaker, the Qiongzhou Strait tended to be in a stable state and gradually formed today’s straits and the subaqueous underwater delta landscape.