Abstract: Altai Mountain is famous for gold, especially for its placer gold. A series of investigations and studies shows that the forming environments of placer are complex and the types are manifold. The contents of this paper contain two sides, one is the classification of placer deposit and another is the distribution of placer.
1. The classification of placer deposit According to the feature of deposits and its forming environments, they are classified as six, that is eluvial, fluvial, proluvial, glacial-fluvioglacial, eolian and composit placer. Among of them, fluvial and glacial-fluvioglacial placers are most important types.
2. The distribution of placer Under the influence of the minerogenetic conditions, the festures of the lacer are different from one another, so is the distribution in Altai Mountain. At high mountain, Quaternary glaciation was strong and played an important role in forming placer. glacial erosion produced not only a series of places where are beneficial to deposition and accumulation of gold, but also a lot of debris which can supply gold for placer plentifully. Therefor the glacial-fluvioglacial placer is main part of placers. Between 1500-2400 m above sea level, the function of flowing water is active and become main energy off forming placer. It results in the trans-portation and sorting and accumulation of placer golds. For reasons given, the fluvia placer appears to be a trend of concentration at middle mountain. The mineralization of hilly land and plain is weaker than that of others, eluvial and proluvial placers have a peak of distribution.