南海西北部陆架表层沉积物稀有金属矿物及相关元素的分布特征与影响因素

Distribution Characteristics and Influencing Factors of Rare Metal Mineral and Related Element in the Surface Sediments from the Continental Shelf of Northwestern South China Sea

对南海西北部近海陆架273个站位表层沉积物稀有金属矿物进行了研究,并结合沉积物粒度和沉积物类型,及与之相关的稀有金属元素分析,探讨了研究区稀有金属矿物的分布特征及主要影响因素。结果表明,本区沉积物中稀有金属矿物的分布主要受沉积物物源、沉积物类型和水动力条件等因素的控制,稀有金属矿物与相关元素的分布存在较大差异,不能仅凭沉积物中相关元素的质量分数分布来确定金属砂矿的有利富集或成矿区。根据沉积物中稀有金属矿物质量分数的分布特征及沉积环境分析,初步划分出5个稀有金属矿物富集区,分别对应于水东湾及附近海域、珠江口南外海、上下川岛与海陵岛之间外海、湛江湾及附近海域和海南岛东南近岸海域,且每个海域富集的稀有金属矿物种类有所不同,有望成为本区不同种类稀有金属砂矿的有利成矿区,其中钛铁矿、锆石和白钛石是本区最有成矿潜力的稀有金属矿种。

The rare metal minerals as well as grain size and sediment types, and rare metal elements were analyzed for 273 surface sediment samples collected from the continental shelf of the northwestern South China Sea to discuss the distribution characteristics and mainly influencing factors of rare metal minerals. Results reveal that the distribution of heavy minerals in research area is mainly determined by provenance, sediment types and hydrodynamic conditions. It is unreasonable to evaluate the distribution of rare metal minerals in dependence on the rare mental elements in sediments due to the notable difference between their distributions. We could roughly divided the rare mental mineral into five regions, i.e. Shuidong bay, the southern part of Pearl River estuary, between Shang/Xiachuang island and Hailing island, Zhangjiang bay and coastal southeast of Hainan island, on the base of the distribution characteristics of heavy minerals and sedimentary environment analysis. These five metal mineral-rich regions tend to enrich corresponding rare metal minerals that are expected to be potential reservoir, especially the most prosperous rare metal minerals, i.e. ilmenite, leucoxene and zircon.