THE ORIGIN OF LIAONING XIUYAN NEPHRITE PLACER RESOURCES AND THEIR PROTECTION
辽宁岫岩软玉砂矿的成因及资源保护

Liaoning Xiuyan Nephrite Placer Deposit(XNPD)is a secondary deposit of primary nephrite ore.the quality of the jades are fine and smooth,and their lustre are comfortable.The gems and jades resources,as a decorative culture,are more and more in people's graces.The discovery and thorough research of XNPD has not only important significance in gemology and archaeology but also other aspects.This paper considers that XNPD belongs to alluvial\|pluvial type.The major types include 1)Alluvial Placer Deposits,which are mainly distributed in the river bed,T1 terrace and flood land of Baishahe;2)Alluvial\|pluvial Placer Deposits,which are mainly distributed in the fans of Wafangdian.In addition,there are also Talus Placer,Diluvium Placer and Coombe Placer.They are all distributed on the upper reaches area of Baishahe,which is in the Xiyu Gou drainage area near the site of primary mineral deposits.They are the products of tectonic activities and climate environment since Quaternary period.The special crust layers of HeMo Jade are the results of elements migration and exchange under supergenesis.They had been formed when the gravels buried near the phreatic water surface and in an open system.This paper also makes suggestions on the exploitation,utilization and protection of the jade resources.