文登近岸海域重矿物组合分布及对沉积动力环境的指示

Distribution of heavy mineral assemblages in Wendeng nearshore waters and their implications for sedimentary dynamic environment

对文登近岸海域97个表层沉积物样品进行了重矿物分离与鉴定,应用相关性分析、Q型聚类分析等数理统计分析手段,研究了重矿物的组合及分布特征,并进行了重矿物分区,辅以沉积物粒度特征对研究区沉积物来源及沉积动力环境进行了分析,进一步探讨了五垒岛湾消退的原因。结果表明,研究区碎屑重矿物以角闪石、绿帘石为主,重矿物组合主要有黑云母-白云母-风化云母-绿泥石组合、钛铁矿-磁铁矿-褐铁矿-锆石-石榴石组合、普通辉石-紫苏辉石-透辉石-电气石组合以及普通角闪石-绿帘石组合共4种。研究区可划分为5个矿物组合区,各矿物区物源及沉积动力环境差异较大。充足的物源供应和适宜的沉积环境导致了五垒岛湾的淤积,五垒岛湾将会进一步萎缩。

97 samples of the heavy minerals of the surface sediments in the Wendeng nearshore waters were separated and identified.The combination and distribution of heavy minerals were studied by means of correlation analysis,Q-type cluster analysis and other mathematical statistics methods.Heavy mineral provinces are established based on the results.Combined with the grain size characteristics of the sediments,we studied sedimentary source and dynamic environment of the area and the shrinkage of Wuleidao Bay.Results show that there are 4 assemblages of heavy minerals,i.e.the biotite-muscoviteweathered mica-chlorite assemblage,ilmenite-magnetite-limonite-zircon-garnet assemblage,augite-hypersthene-diopside—tourmaline assemblage and hornblende—epidote assemblage.And there are five heavy mineral provinces in the study area.The provenance and sedimentary dynamic environment of each mineral province are quite different.Adequate sediment supply and dynamic environment lead to the siltation of Wuleidao Bay,and it will continue to shrink in the future.