摘要
涠洲岛由第四纪玄武岩浆喷发时在水下堆积而形成。该岛经受长期的地质作用和演变过程,形成了各种各样的地貌类型。据调查、分析,该岛地貌可分为火山地貌、流水地貌、海蚀地貌、海积地貌、珊瑚岸礁地貌、海积—冲积地貌、重力地貌、人工地貌等八大类型。其中,海蚀地貌、海积地貌、珊瑚礁地貌,火山遗迹地貌等较为明显。岛的南部沿岸海蚀地貌发育,海蚀崖高达30～50m,海蚀平台宽20～70m,有35个大小不等海蚀洞。岛的北部沿岸海成沙堤十分发育,呈条带状、牛轭状分布,长100～2000m,宽40～700m。按其形成的年代,形态,结构及空间分布特征分为老、中、新沙堤。老沙堤形成于距今6900～4000a前,中沙堤形成于距今3100～2200a前,新沙堤形成于距今2000～1200a前。岛屿北部、东部沿岸珊瑚岸礁相当发育,礁坪宽400～1025m,珊瑚生长带宽200～660m;西南部发育较差,礁坪宽20～475m,珊瑚生长带宽50～215m。南部沿岸没有珊瑚礁存在,其珊瑚礁形成于6900a前。涠洲岛总的地貌特征是南部沿岸以海蚀地貌为主,北部沿岸以海积地貌和珊瑚礁地貌为主,岛上不同程度地保存有火山活动的遗迹。总的地势则为南高北低,自南向北缓缓倾斜。
The Weizhou Island was formed by the underwater accumulation during the eruption of Quatenary basalt magma, and different geomorphologic types on the island were formed in a longterm geologic evolution process. It is shown from the survey results that the geomorphologic types on the island include volcanic form, runningwater form, abrasion form, marine accumulative form, coral reef form, marine accumulativealluvial form, gravity form and artificial form. Among them, abrasion form, coral reef form, marine accumulative form and volcamic form are prominent. The abrasion forms, such as sea cliff as high as 30~50m, abrasion platform as wide as 20~70m and sea cave (a total of 35 caves), are developed along the south coast of the island. The marine sand levees 100 to 2000m long and 40 to 700m wide are developed along the north coast of the island and take on banded or oxbow distributions. According to their formation age, shape, texture and spatial distribution, the sand levees can be divided into old one, middleaged one and new one, and the old, middleaged and new levees were formed in 6,900 to 4000 aBP, 3100 to 2200 aBP and 2000 to 1200 aBP, respectively. The coral reefs are well developed along the north and east coasts of the island, the reef flats are 400 to 1025m wide, and the coral growing zones are 200 to 660m wide; the coral reefs are poorly developed along the southwest coast, the reef flats are 20 to 475m wide, and the coral growing zones are 50 to 215m wide; no coral reef is developed along the south coast, and the coral reefs there were formed 6900a ago.In general, the geomorphology of the Weizhou Island is characterized by abrasion form along the south coast and marine accumulative form and coral reef form along the north coast, and the volcanic form is present to some extent on the island. The overall relief of the island is high in the south and low in the north, and slopes down gently from south to north.
出处
《海洋科学进展》
CAS
CSCD
北大核心
2003年第1期41-50,共10页
Advances in Marine Science
关键词
涠洲岛
地貌类型
分布规律
形成特征
Weizhou Island
geomorphologic type
distribution regulation
formation feature
