The types of deposits basically are differential metasomatism in the later magma, pneumatolytic hydrothermal process, pegmatite process, residual deposits and placer deposits.
矿床类型以岩浆晚期分异交代型、气成热液型、伟晶岩型、风化壳型和砂矿型为主。
Placer deposits
英语例句库
Four alluvial deposits distributing along Yuanjiang river and the diamondiferous rocks that supply diamonds to these placer deposits have striking properties of varied sources and multi-phases.
沅水流域分布4个金刚石砂矿床，供给金刚石砂矿的含金刚石岩体具多期多源特点。
中文百科
漂砂沉积 Placer deposit
（重定向自Placer deposits）
漂砂沉积（placer）是地质或矿业学上的专有名词。
在河水搬运沉积物（或其他搬运作用）的过程中，比重较大之岩屑或矿物常常会堆积在某些水流比较弱的地方，例如河道的两旁或河床的坑孔，久而久之这些沉积物的量就会越来越多。这就是漂砂沉积，如果沉积物是具有经济价值的，那么就有成为矿床的可能性。
最为人所熟知的漂砂沉积物是金。由于金比重大，常富集于河床的坑洞，也不需要利用昂贵的仪器采集(只需要一个筛网就够了)，因此当发现后，时常吸引许多人一同开采，这也是"淘金"一词的由来。 其他常见的漂砂沉积物，而且具有开采价值的还有白金、锡、钻石、重砂(独居石成分为主，常含有微量稀土元素如钍、铀)、锆石等等。
英语百科
Placer deposit 漂砂沉积
（重定向自Placer deposits）
In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation during sedimentary processes. The name is from the Spanish word placer, meaning "alluvial sand". Placer mining is an important source of gold, and was the main technique used in the early years of many gold rushes, including the California Gold Rush. Types of placer deposits include alluvium, eluvium, beach placers, and paleoplacers.
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