With three years of National Science Foundation support, Dr. Herbert Haas will continue the operation of the Southern Methodist University radiocarbon laboratory and increase its ability to date archaeologically significant samples. Through his widespread contacts with the anthropological community, Dr. Haas collaborates with archaeologists working in many parts of the world and provides absolute ages for organic samples which they submit. Currently, the laboratory supports projects involving over 89 archaeologists working in more than 31 states and countries. With NSF support, this collaboration will continue. Secondly, Dr. Haas will work to refine the radiocarbon dating technique itself and will concentrate in two areas. He will develop better procedures for dating the humic acids in soils. To achieve this, he will date samples from secure stratigraphic contexts where independent means for age evaluation are available. He will also analyze multiple samples from a single soil horizons which extend over large geographical areas. Secondly, Dr. Haas will focus on dates which lie near the limits of the radiocarbon technique. While in theory determinations up to 55,000 years old are possible, most laboratories are equipped to work accurately over only a ca. 35-40,000 time span. Dr. Haas will concentrate on the 35-55,000 interval. He will develop techniques for sample evaluation and for elimination of sources of potential contamination which may be introduced during the dating process. The goal of anthropological archaeology is to trace the process of cultural development over time. To accomplish this, it is essential that materials and excavated sites be chronologically accurately placed. The radiocarbon technique provides an important way to accomplish this and it is crucial to the discipline that laboratories sympathetic to these goal be supported. The SMU laboratory is well known both for the carefulness of its work and its willingness to analyze difficult samples. With NSF support, this important resource will be maintained. The research conducted will not only provide dates for archaeological use but also refine the dating technique itself.