摘要
海南岛属热带季风岛屿型气候 ,为南海大陆架岛屿 ,中央为山地 ,临海为多种类型海岸 ,以处于动态平衡的海蚀—海积型海岸为主。海南岛主要是基岩岬湾海岸 ,潮汐属日潮型 ,东部与南部为不规则日潮混合潮。海岸受构造运动与气候变化的双重影响 ,更新世初期 ,海岸属基岩港湾型 ,晚更新世构造运动频繁 ,使不少海湾底部抬升为阶地。构造抬升运动持续到全新世 ,使一些珊瑚礁抬升为高出海面数米的阶地。海岸类型按其成因与形态可分为两大类 :基岩港湾海岸与砂砾质平原海岸。基岩港湾海岸分布于山地与丘陵临海处 ,砂砾质平原海岸 (或为三角洲平原海岸 )其表现形式多为沙坝与泻湖海岸 ,沙坝上叠置发育着海滩、沙堤或沙丘 ,随着海岸加积展宽或地壳上升 ,老的沙坝可抬高成为海积阶地。潮流作用对港湾众多的海南岛的发育演变以及开发利用亦有重要作用。潮汐汊道港湾规模较大 ,水域面积达数十平方公里。
Hainan Island is located on the northwest of the South China Sea,belonging to tropical monsoon island climate,changing in half year period.The island is warm all the year round and accepts much sunshine.Hainan is a South China Sea shelf island,with mountains in the middle and multiple coast types along the edge.Its basement is pre Devonian sandy shale and metamorphic rocks,which became hard and rigid during Caledonian movement,and then late Devonian, Carboniferous-Permian sandy shale,limestone,clastic rock and carbonate rock in sea land alternations.The rivers are fed by precipitations,have their sources in the central mountains and radiate into sea.There are 1 510 single current streams that provide rich hydraulic resources but in uneven distributions.The island mainly has 5 natural resources,namely,agricultural and tropical economic plants,mineral resources,oil and natural gas,touring resources,aquatic products and estuarine resources.Hainan mainly owns bedrock embayment coast,with a 1 528 4 km long coastline,64 estuaries and more than 300 islets.The tide is characterized by solar tide.The east and south parts of the island see irregular mixed tides,with solar tides for 15～18 days and semidiurnal ones for 11 days on the average;the west and north coasts see regular diurnal tides,with tidal range of 1～ 3 m. The island coast has been influenced by both tectonic movements and climatic changes.For examples,in the early time of Pleistocene,the coast belonged to bedrock embayment type,and during frequent tectonic movements in late Pleistocene,some bay floor was uplifted and became terraces;the tectonic uplifting movements lasted until Holocene when some coral reefs were uplifted to several meters higher than the sea level.Coast can be grouped under bedrock embayment and sandy gravel plain coast types according to origin and forms.Tidal actions have also played an important role in the evolution and utilization of the island.Tidal branch estuaries are on a large scale and covering a water area of up to several tens of square kilometers.
出处
《海洋地质动态》
2002年第3期1-9,共9页
Marine Geology Letters
