南海表层沉积物的磁学性质及其对物源的指示意义

The research on sediment sources and transports in South China sea (SCS) can provide correct information about geology and paleoenvironment recorded in sediments. An important advantage of environmental magnetism is that the methods employed are relatively rapid, nondestructive. Moreover, the methods can be used to characterize variations in the abundance, types, and grain sizes of magnetic minerals incorporated in the sediments, and thus provide useful information for sediment provenance. However, the use of magnetic data for sediment provenance in SCS has been limited. In this work, we investigate the magnetic properties of the surface sediments in the SCS in an attempt to provide environmental magnetic evidence for potential transport mechanisms of sediments. We use the spatial distribution of magnetic parameter and the contributions of individual magnetic mineral populations in IRM curves which represent the types and contributions of individual magnetic mineral to deduce the seiments source and transport precesses in the SCS. Meawhile we study the dynamic factor which control the sediment transport combined with physical oceanic data. Results from this study will provide a new way for sediment provenance, and experiment data for further environmental magnetism research in the SCS.

认识南海现代沉积物物质来源及进入南海后的搬运路径对于正确理解南海沉积物所记录的地质、环境信息具有重要意义。环境磁学研究可以提取沉积物中磁性矿物种类、粒径大小及其相对含量变化的信息，而且磁学测量方法具有快速、准确、非破坏性的优点，但是目前在南海沉积学研究中还没得到广泛的应用。本项目拟通过测量能反映磁性矿物种类、粒径大小及相对含量的特征参数开展南海表层沉积物的物源研究。通过磁学参数和不同矫顽力组分的含量所反映的磁性矿物种类和含量在空间上的展布特征，探讨南海沉积物物质来源及沉积物进入南海后的搬运轨迹，并结合物理海洋过程，探讨控制物源搬运的动力学因素。本研究将为南海物源判识提供新思路,为今后南海环境磁学研究积累基础资料。

认识南海现代沉积物物质来源及进入南海后的搬运路径对于正确理解南海沉积物所记录的地质、环境信息具有重要意义。环境磁学研究可以提取沉积物中磁性矿物种类、粒径大小及其相对含量变化的信息，而且磁学测量方法具有快速、准确、非破坏性的优点，但是目前在南海沉积学研究中还没得到广泛的应用。本项目以整个南海海区的表层沉积物为研究对象，以磁学为手段，在空间尺度上探讨南海沉积物物质来源及搬运轨迹。我们通过磁学参数和不同矫顽力组分特征建立了四个不同物源区的磁学判别指标，认识了南海表层沉积物物质来源。通过磁学参数和矫顽力组分的含量在空间上的展布形式，探讨了不同物源区沉积物进去认识沉积物进入南海后的搬运轨迹，并结合物理海洋过程，给出了控制物源搬运的动力学因素。该研究成果为南海物源判识提供了新思路，为今后南海环境磁学研究积累了基础资料。