福建海坛岛风沙物质来源研究

Study on the Sand Sources in Haitan Island,Fujian

海坛岛是福建沿海岛屿风沙侵害严重的典型地区,选择海坛岛古风沙(老红砂)、现代风沙、周边的海滩砂与闽江河口沙进行对比研究,对各类泥沙做了粒度分析、矿物组成和形态特征分析以及稀土元素示踪分析,对比各类泥沙的理化特征,判别泥沙的源汇关系。研究表明:海坛岛老红砂、现代风沙与闽江河口沙关系密切,与海滩砂、大陆架砂关系疏远。海坛岛风沙主要来自闽江河口沙;海滩砂可能来自远源的闽浙沿岸流泥沙或大陆架砂。在末次间冰期暖湿气候与现代暖湿气候的影响下,闽江携带大量泥沙进入海坛海峡和海坛岛沿岸,在季风搬运下形成老红砂和现代风沙同处沿岸沉积。

Haitan Island is a typical area which has serious wind-sand disaster in Fujian coastal islands. The ancient sand（ old red sand）,modern sand,beach sand of Haitan Island and estuarine sand of Minjiang River were selected for comparative study. In order to understand the source and sinks of sands,the grain-size analysis,constitutive and morphological characteristics analysis and rare earth elements（ REE） tracer analysis were used for distinguishing the physical and chemical characteristics of various sands. The results show that there is a close relationship among the old red sand,modern sand and the estuarine sand of Minjiang River. And the correlation is poor among the old red sand,beach sand and continental shelf sand. The provenance of Haitan Island sand was from the sand of Minjiang River,The beach sand is probably derived from the remote Fujian,Zhejiang coastal current sand or continental shelf sand. A large amount of sands were discharged from Minjiang estuary and entered Haitan strait and Haitan Island Coast under the conditions of warm and wet climate in the Quaternary period and modern period. And then these sands were deposited along the coast to form the oldred sand and modern sand under the monsoon transportation.