| 摘要: |
| 全新世以来,世界海面大幅度上升,渤海海区发生了明显的海侵,玉木冰期低海面时期的近海广大陆域皆沉溺于海平面以下。辽东湾由于地质构造复杂及沉积作用速度分布不均匀等因素,海底保存了一部分玉木冰期低海面时期陆地或滨海区的地貌形态及相应的老沉积物的遗迹。它们虽然经过了后期水动力条件及沉积作用的改造,但是,仍不同程度地反映出原始地貌的迹象和某种残留沉积的特征。
关于辽东湾残留地貌和残留沉积的问题,过去曾有报道;本文在以往调査的基础上,结合近期有关资料,对此作进一步的探讨。 |
| 关键词: 海底残留地貌 残留沉积 辽东湾 |
| DOI： |
| 分类号: |
| 基金项目:中国科学院海洋研究所调查研究报告第822号 |
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| PALEO-GEOMORPHOLOGICAL UNITS AND RELICTS LEFT OVER FROM THE LATE PLEISTOCENE IN THE LIAODONG BAY |
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Li Fan, Lin Meihua
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Institute of Oceanology, Academia Sinica
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| Abstract: |
| One of the most remarkable paleo-geomorphological units in the Liaodong Bay is Liaodong Shoal, which was shore sedimentation during the low sea level in late Pleistocene or early Holocene and have since been violently reformed.
Liaozhong Depression, which might have been a paleo-lake or paleo-lagoon, is located to the north of Liaodong Shoal. In the Liaodong Bay, there are many buried paleo-channels,among which Dalinghe-liaohe paleo-channel is the longest. Those paleo-channels once injected into Liaozhong paleo-lake(or paleo-lagoon ) from different directions In addition, therevare paleo-barriers, paleo-dunes, which were formed during low sea level, and some relicts can still be found on them. They might have been paleo shore sediments.
The development of above mentioned paleo-geomorphological units and relicts depends upon many factors, such as hydrodynamical regime, ununiformity of the distribution of the deposits velocity in different regions, and the change of the sea level etc. Although the solid discharges to the Bohai Sea by the Huanghe River are estimated at 1, 200 million tons annually, approximately 70% of the deposits are in shallow area near the river mouth. In addition, submarine erosion is advantageous to the development of those paleo-geomorphological units and relicts.
Based on the paleo-geomorphological data two paleo-shorelines might have existed in the Liaodong Bay, one at the water depth of about 30 m and might have been formed 9000-10000 years ago, and one at the depth of about 20-25 m and formed about 7000-8000 years ago.
According to the characteristics of its paleo-shoreline and three shell banks of the west coast of the Bohai Bay, the region might have gone 5 times through relatively halting or pulsative changes since late pleistocene or early Hlolocene. |
| Key words: PALEO-GEOMORPHOLOGICAL UNITS RELICTS LEFT OVER LIAODONG BAY |
