涠洲岛是我国最大的第四纪火山岛,位于南海珊瑚礁分布的北界,是我国珊瑚礁重要分布区之一.本研究采集涠洲岛各珊瑚礁区海滩岩中沉积的珊瑚碎屑等生物样品,挑选未经过成岩改造的原生珊瑚文石部分,进行放射性碳同位素(14C)测年和海洋储库效应校正后,建立涠洲岛全新世珊瑚礁发育的年代框架;通过对比我国各全新世珊瑚礁发育情况,推演出涠洲岛全新世珊瑚礁的形成过程.结果显示,涠洲岛珊瑚礁的起始发育时间与我国其他全新世珊瑚礁基本一致,均属于全新世大暖期.涠洲岛全新世珊瑚礁发育及演变过程可以分为4个阶段:在早全新世时期(12 000-8 000 a B.P.),涠洲岛全岛的火山碎屑岩台地形成,这为珊瑚附着生长提供了附着基质;在中全新世早期(8 000-4 000 a B.P.),涠洲岛北面沿岸的珊瑚岸礁及沙坝-潟湖沉积体的雏形最先形成;在中全新世晚期(4 000-2 000 a B.P.),涠洲岛东面和西北方向的沿岸形成沙坝-潟湖沉积体;在晚全新世时期(2 000-900 a B.P.),涠洲岛东面至东北和西南方向沿岸的珊瑚礁开始广泛发育.可以推断,涠洲岛珊瑚礁形成于早全新世时期,从岛北岸开始发育,然后到岛的东面以及东北和西南方向,最终演变成涠洲岛现代珊瑚礁分布格局.
Abstract
Weizhou Island is the largest Quaternary volcanic island in China.It is located in the northern boundary of coral reef distribution in the South China Sea and is one of the important coral reef distribution areas in China.In this study,biological samples such as coral debris deposited in beach rocks of coral reef are-as in the Weizhou Island were collected,and the aragonite parts of primary corals without diagenesis were se-lected.After radiocarbon isotope(14C)dating and correction of the marine reservoir effect,the chronological framework of Holocene coral reef development in the Weizhou Island was established.The results show that the initial development time of coral reefs in the Weizhou Island is basically the same as that of other Hol-ocene coral reefs in China,which belongs to the Holocene warm period.The development and evolution of the Holocene coral reef in the Weizhou Island can be categorized into four distinct stages:during the early Hol-ocene(12 000-8 000 a B.P.),the volcanic clastic platform was formed throughout the island,which created an attachment matrix for coral attachment and growth.In the early Middle Holocene(8 000-4 000 a B.P.),the prototype of coral shore reefs and sandbar lagoon deposits along the northern coast of the Weizhou Island was first formed.In the late Middle Holocene(4 000-2 000 a B.P.),bar-lagoon deposits were formed along the east and northwest coasts of the Weizhou Island.During the late Holocene(2 000-900 a B.P.),coral reefs began to develop widely from the east to the northeast and southwest of the Weizhou Island.It can be inferred that the coral reefs of the Weizhou Island were formed in the early Holocene period,and began to de-velop from the north shore of the island,then to the east,northeast and southwest of the island,and eventu-ally evolved into the distribution pattern of modern coral reefs in the Weizhou Island.
关键词
涠洲岛/全新世/珊瑚礁/14C/形成和演变
Key words
Weizhou Island/Holocene/coral reef/14C/formation and evolution
维普
万方数据