广西铁山港表层沉积物碎屑矿物组成、分布及水动力环境分析

Composition and distribution of detrital minerals in surface sediments and their relations with hydrodynamic environment in the Tieshan Bay, Guangxi Province

为了资源、环境和港口建设的需要,对取自铁山港海域68个表层沉积物样品进行了系统的矿物鉴定和统计,结果表明:沉积物中矿物种类丰富,其中轻矿物以石英为主;重矿物以电气石、锆石、钛铁矿的高含量为特征,褐铁矿也有一定量的分布。轻、重矿物成熟度指数高,表明沉积物遭受过强烈化学风化作用,重矿物组合为电气石+钛铁矿+锆石。湾内多个站位出现锆石砂矿品位异常,锆石资源前景良好。多种矿物分布在湾的中南部,呈现明显的等值线高低不同的韵律性环状分布,湾中矿物主要来源于广西近岸陆地,其分布受地形和水动力的共同影响,入海泥沙在湾内主要受控于潮流影响,涨潮流与落潮流的流路和流速的不同是湾中矿物分布变化的主要原因。

Detrital mineral characteristics of 68 surface sedimentary analyzed in detail for natural resources assessment, environmental samples collected from the Tieshan Bay were protection and port construction. The results show that light minerals were dominated by quartz and heavy minerals of these sediments were characterized by relatively high contents of tourmaline, zircon and ilmenite, and limonite also accounts for a certain amount. The high mineral grade of maturity suggests that the sediment was suffered strong chemical weathering. The heavy mineral combination is tourmaline-ilmenite-zircon. Zircon content is higher at some locations in the bay, indicating good resource perspective of zircon. In the bay, the clastic minerals come principally from the offshore land and some minerals distribution in the south-central of the Tieshan Bay shows obvious features of the rhythmicity, which have been influenced by underwater topography and hydrodynamic conditions. Further, the sediment movement has mainly been controlled by tidal current. The difference of tidal flood current and ebb current flow path and flowvelocity is the primary cause of the spatial distribution changes of these sedimental minerals in the bay.