粤东后江湾海进海岸沉积特征和地貌发育

依据地质钻探和海滩观测资料，分析了后江湾海岸在海进作用下，海岸形成海进地层层序。滨面遭受侵蚀并正在后退和变陡。晚更新统陆相杂色粘土层和砾砂层直接暴露于海底。在海域供沙不足的情况下，整个海湾的海滩被侵蚀后退，而海滩各岸段侵蚀程度存在差异。

SEDIMENTARY CHARACTERISTICS AND TOPOGRAPHICAL GROWTH OF THE TRANSGRESSIVE COAST OF HOUJIANG BAY, EAST GUANGDONG

Sedimentary characteristics of the transgressive coast of Huojiang Bay are discussed using drill and survey data. The major characteristics are: (1) The present beach overlaped the Pleistocene tombolo forming the vertical transgressive sequences because of landward transport of beach sand; (2) Lagoon sedimentation was initiated approximately 4910 yrs B. P. (based on radiocarbon dating) developed on an eroded Pleistocene surface.Vertical sedimentary sequences are from bottom to top, Pleistocene oxidation stratum,tidal shallow and coastal lagoon with the ongoing Holocene relative rise in sea level;(3) Shoreface horizontal retreat rates increase from shoreline to 5m isobath to 10m isobath and range from 1. 3-2m/yr, 1. 3-8m/yr and 4-9. 3m/yr respectively. So the shoreface becomes steeper; (4) The eroding area which distributes along shore approximately exists on the sea bottom. Pleistocene clay and gravel sand lay bare on the sea bottom at some places in this area, at other places shallow marine sedimends are only a thickness of 0.3-0. 4m; (5) Beach erosion is common in Huojiang Bay. Sand source of the beach comes mainly from off shore, but not from the headlands on the present transgression.