CHARACTERISTICS AND INFLUENCE FACTORS OF VALUABLE HEAVY MINERALS IN SURFACE SEDIMENTS OF THE EASTERN BOHAI SEA AND THE NORTHEN YELLOW SEA
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摘要: 通过对渤海东部和黄海北部海域234个表层沉积物样品进行重矿物鉴定,计算了独居石、石榴石、钛铁矿和锆石4种有用重砂矿物的品位并分析了异常分布特征,结果显示,异常品位主要富集在渤海海峡北部、辽东半岛东南侧和北黄海南部海域。粒度分析表明,在砂质含量越高、分选性越好的沉积物中重砂矿物越利于富集;矿物组分主要来自鸭绿江、辽东半岛东南侧海岸和长山列岛冲刷物质、老铁山水道侵蚀物质及全新世前残留沉积物质;水动力条件影响明显:沿岸流有效搬运了近源河流的输入物质,北黄海强潮流促进了重矿物砂矿的形成富集,而黄海暖流则有效限制了黄河源细粒物质的扩散,对已富集区域起到了重要保护作用。Abstract: In this paper, we synthetically analyzed the heavy sands picked out from the 234 surface sediment samples taken from the Eastern Bohai Sea and the Northen Yellow Sea. It seems that the heavy minerals of monazite, garnet, ilmenite and zircon are economically valuable and thus their grades are measured and calculated. High grade areas are located in the northern Bohai Strait, the southeast Liaodong Peninsula and the southern North Yellow Sea. Grain size analysis indicates that the sediments are high in sand content with better sorting. It is inferred that the Yalu River, southeast coast of the Liaodong Peninsula, Changshan Archipelago, Laotieshan Channel and the relict deposits before the Holocene are provenances of the heavy minerals. The enrichment of valuable heavy sands depends upon hydrodynamic conditions, such as, a) coastal current, which effectively transported the sediments from proximal rivers; b) strong tidal current from the north Yellow Sea, which worked for the enrichment of heavy placer minerals; c) the Yellow Sea warm current, which effectively constrained the diffusion of fine grained material from the Yellow River and protected the enrichment region of valuable heavy minerals.
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Key words:
- surface sediments /
- valuable heavy minerals /
- anomaly grade /
- eastern Bohai Sea /
- northern Yellow Sea
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