Placer tin deposit in xupu occurs in alluvial sediment of quatemary system and cassiterite chiefly concentrates at the bottom of gravel layers.

溆浦砂锡矿床赋存在第四系冲积层中锡石主要富集在底部砂砾石层。

Placer tin deposit in Xupu occurs in alluvial sediment of Quatemary SyStem and CaSSiterite chiefly concentrates at the bottom of Gravel layers.

溆浦砂锡矿床赋存在第四系冲积层中，锡石主要富集在底部砂砾石层。

Sand wave movement is an important form of sediment movement for alluvial rivers and has a great effect on stream resistance.

沙波运动是冲积河流泥沙运动的一种重要形式。沙波的消长对河道水流的阻力损失有很大的影响。