Modern coastal sedimentation in Beihai,Guangxi
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摘要: 本文讨论了广西北海现代海岸各种环境的自然地理分带、地质营力、沉积物以及生物生态等特征,指出环境能量直接决定了环境类型、沉积物类型以及生物组合类型。海岸环境据其能量划分为高能海滩、低能海湾、中能岩质潮坪和砂质潮坪、低能泥质红树林潮坪以及高能潮上沙丘等6种沉积类型;混合沉积作用主要发育于高能海滩和中能潮坪沉积环境内。涠洲岛现代地壳的上升活动控制着该区海蚀地貌的形成。Abstract: The present paper gives a detailed description of geographic zoning,geological agents,sedimentary and ecological characteristics along the modern coasts in Beihai,Guangxi.The types of environments,sediments and organic associations tend to depend on environmental energy.The coastal environments may be subdivided,on the basis of hydrodynamic energy,into six types:(1) high-energy beach;(2) low-energy gulf;(3) medium-energy rocky tidal flat;(4) medium-energy sandy tidal flat;(5) low-energy muddy mangrove tidal flat,and(6) high-energy spratidal dune.The mixed sedimentation of terrigenous quartz and carbonate grains is much developed in high-energy beach and medium-energy rocky and sandy tidal flat environments.At present,intense erosion is developing along the southern coast of the Weizhou Island south of Beihai whereas extensive deposition may be observed along the northern coast.Since the Weizhou Island is rising at a mean velocity of 3.7 cm/yr,the deposition of modern beaches and tidal flats around the Weizhou Island is developed in the environments of relative lowering of sea level.
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Keywords:
- sedimentation /
- modern coast /
- tidal flat /
- Beihai /
- Guangxi
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