Patination of Knife River Flint Artifacts

Abstract

Various types of weathering rinds, or patinas, formed on chipped stone artifacts have long been noted by archaeologists and are in the following article the subject of a selective literature review. Most investigators agree that the presence of patination on chipped stone artifacts is at best only a gross indicator of artifact age. Studies of patinated artifact assemblages may, however, provide information pertaining to natural processes acting within the sediments in which the artifacts occur. Patination in Knife River flint artifacts is shown to be the result of silica dissolution, or desilicification. No additive chemical or mineralogical changes associated with the process have been noted. The shape and depth of this kind of rind varies greatly for any given Knife River flint artifact and is governed by internal structural controls. Several factors that influence silica solubility in the weathering profile are discussed. To date, the many environmental variables that influence the rate of Knife River flint patination have limited the potential uses of patination information in the interpretation of the archaeological record.