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本文根据北部湾北岸防城湾地区河口的地貌特征和地层、古生物以及~(14)C年龄资料论述了这一地区全新世以来的海侵过程及河口三角洲的演变过程。文中比较详细地叙述了不同沉积相的岩石学特点和相应古生物组合的各个种属,并具体分出两个沉积旋迥以及与之对应的两期三角洲。认为本区在全新世中期6000年前开始接受海侵,然后在两次海面波动过程中形成两期三角洲,随着海侵的发展,河口后退,第一期三角洲形成于1800年前,分布在防城河口—5m以内至牛头岭地区,第二期即现代三角洲分布在将军岭以北至针鱼岭的防城湾顶。
Based on the geomorphic features, stratigraphy, palaeontology and ~ (14) C age data of estuaries in the northern coast of Beibu Gulf, this paper discusses the transgression process and the evolution of estuarine delta since Holocene in this area. In this paper, we narrate the petrologic characteristics of different sedimentary facies and the corresponding species of the corresponding paleontological assemblages in more detail, and divide the two sedimentary cycles and the corresponding two phases of delta. It is believed that the area began to undergo transgression 6,000 years ago in the mid-Holocene and then formed two phases of delta during the two sea-level fluctuations. With the development of transgression, the estuary retreated and the first phase of the delta formed 1800 years ago Fangcheng estuary -5m to Niu Tau Ridge area, the second phase of the modern delta distribution in the general ridge north to pin fish Ridge Fangchengwan Ding.