The Yulin Grottoes site is located in Guazhou Countyand contains 42 caves,5000 m2of wall paintings,and 200 painted statues.The wall paintings have suffered various types of deterioration,including efflorescence,flaking,detachment,and more,all of which are caused or affected in some way by salt movement insidethe cliff conglomerate onto which they are painted.In order to find out the moisture and salt distribution characteristics in the cliff,a ten-meter well was dug out of the top of the east side of cave number 6,the evidence from which was used to research the formation process and water and salt content in the cliff.The results are as follows:the rock structure is of the Pleistocene Jiuquan conglomerate group;the water content is between 0.55%2.94% and the average water content is 1.79%; analysis of the soluble salt content is 0.16%, the main anions are SO42- and Cl-, and the main cations are Ca2+and Na+. The evidence yielded from this analysis can provide practical data useful for preventing salt-related damages to the murals at Yulin.
