珠江口伶仃洋表层沉积物的重矿物特征及其对陆架水入侵的反映

Character of the Heavy Mineral in the Sudace Sediment of Lingding Yang in the Pearl River Mouth and Their Rdection to the Invasion of Shelf’s Water

珠江口伶仃洋表层沉积物中业经鉴定的重矿物共有近３０种（类）．根据重矿物种类和含量的分布特点，可将海区划分为４个重矿物组合类型及相应的４个矿物区，浅海残留砂矿物区主要受陆架水入侵控制；河口湾矿物区主要受陆架水入侵的顶托影响；混合矿物区处于陆架水入侵控制一顶托影响的过渡地段。伶仃洋由于受下泄径流和陆架水入侵的夹击作用，致使其底质沉积物的粒度及重矿物的含量，由陆向海分别呈现“粗－细－粗”和“高－低－高”的变化趋势。

There are thirty Kinds of heavy mineral identified in the surface sediment ofLingding yang. Accrding to charaeter of content and distribution of heavy minerals,andcharacteristic minerals appeared, the Lingding yang is divided into four heavy mineralconbinations and four mineral subsections.Mineral section of the shallow sea-relict sandis invaded by the shelf’s water. Mineral section of the estuary bay is withstanded byshelf’s water. Mixed mineral section is Located at the excessive section between inrasionand withstand of the shelf’s water. Because of the Lingding yang is coerced by leakingriver water and by the shelf’s water invasion,grain size and content of heavy minerals inthe surface sediment are resuIted to present a changing trend from“coarser to finer tocoarser”and“higher to lower to higher”ascope from land to sea.