在沙丘移动过程中，背风坡底部经常掩埋致死低矮沙生植物，而迎风坡坡脚则因风蚀而出露植物残体。通过¹⁴C测年法测定植物死亡时间，并根据沿沙丘移动方向从迎风坡坡脚至背风坡边缘的水平距离，即可计算沙丘在这段时间内的平均移动速率。据此，利用灌木植物木质茎残体作为测年材料，得到了民勤绿洲上风向外围区域内3个新月形沙丘的移动速率。通过与高分遥感影像解译结果对比，发现¹⁴C测年法能够成功确定新月形沙丘在数十年内的最大平均移动速率。

In the migration of active dunes， small psammophytes often die while being buried by the lee of the dune， and subsequently plant residues appear at the toe of the windward because of wind erosion. The mean migration speed of the dune during this time can be computed according to the death time measured by carbon-14 dating and the horizontal distance from the windward toe to the lee edge along the migration direction. Based upon this principle and selecting the residues of shrub stems as dating materials， the migration speeds of three barchans at the upwind marginal area of the Minqin oasis are obtained. Compared with the more accurate results given by the interpretation of remote sensing images， it is found that carbon-14 dating can successfully determine the maximum time-averaged migration speed of barchans during several decades.