OCCURRENCE AND AGE OF PACKRAT MIDDENS FROM WESTERN NORTH DAKOTA

Packrat middens are found throughout the arid regions of the western United States and are used by scientists for paleoenvironmental analysis and paleoclimatic reconstructions. Although middens have been identified in southern Montana and western South Dakota, there is no scientific record of preserved packrat middens from North Dakota. The objectives of this project were to locate preserved packrat middens in North Dakota, to date the middens using both AMS radiocarbon techniques and through OSL analysis, and finally to catalog the macrofossils represented within the middens. During this investigation several moderately-indurated middens were successfully located in the Little Missouri National Grasslands of southwestern North Dakota. Three of these middens were sampled for further analysis. The sampled middens contained high portions of sand within the amberat matrix, which provided an opportunity for OSL dating and ample fecal pellets for AMS radiocarbon dating. This presentation will discuss the occurrence, context and general characteristics of the North Dakota middens, but is primarily focused on the age dating results. Future work will target macrofossil analysis and paleoenvironmental reconstruction for the sites in western North Dakota that expectantly include a record of biotic assemblages prior to European settlement.