Our Research interests are two-fold: archaeological chemistry, emphasizing dating and DNA/phylogenetic analysis of prehistoric rock paintings (pictographs) for which we have developed the only general direct technique currently available for dating pictographs; and cosmochemistry, emphasizing noble gas mass spectrometry of meteorites. These diverse studies have one thing in common; each involves using ancient, extremely rare minute samples. Experimental techniques often used are scanning electron microscopy, electron micrprobe analysis, isotope mass spectrometry, plasma chemical reactions and polymerase chain reactions (PCR) and phylogegenetic analysis of DNA.

            Until recently, rock art was largely ignored by archaeologists because there was no means for accurately placing them into the temporal record for association with other material remains at a site. The method we recently developed allows such small samples to be dated that determining the age of an ancient pictograph is now feasible. Pictograph samples from all over the world are being dated. We have also shown in the last year, using DNA and phylogenetic analysis, that an organic material from a hoofed mammal, probably bison, was added to the paint as a binder/vehicle of pictographs from southwest
Texas. The area near the confluences of the Devils, Pecos, and Rio Grande Rivers, has some of the world's most impressive rock paintings (pictographs).

            Two radioactive isotopes are particularly important for dating events concerning meteorites: 244Pu which fissions into 131-136Xe and 129I which decays into 129Xe. Meteorites offer the oldest known material in our solar system. Measurement of the noble gases permits us to determine the age of meteorites, the time when the elements were formed and the length of time the meteorite spent in space as a meter-sized body.
 
 

            Radiocarbon Dates on the All American Man Pictograph, S. D. Chaffee, M. Hyman, M. W. Rowe, N. J. Coulam, A. Schroedl, and K. Hogue, American Antiquity, 59, 769-781 (1994).

            Radiocarbon Dating of Rock Art, J. Russ, M. Hyman, and M. W. Rowe, Archaeology and Natural Science, 1, 127-142 (1993).

            Oxygen Isotopes in Separated Components of CI and CM Meteorites," M. W. Rowe, R. N. Clayton, and T. K. Mayeda, Geochimica et Cosmochimica Acta, 58, 5341-5347 (1994).

            Direct Radiocarbon Dating of Rock Art, J. Russ, M. Hyman and M. W. Rowe, Radiocarbon, 34, 867-872 (1992).

            Dating a Pictograph in the Pryor Mountains, Montana, S. D. Chaffee, L. L. Loendorf, M. Hyman, and M. W. Rowe, Plains Anthropologist, 39, 195-201 (1994).

            Radiocarbon Dating of Prehistoric Rock Paintings by Selective Oxidation of Organic Carbon, J. Russ, M. Hyman, H. J. Shafer, and M. W. Rowe, Nature, 348, 710-711 (1990).

            Radiocarbon Dating of Roc Paintings," S. D. Chaffee, M. Hyman, and M. W. Rowe, New Light on Old Art, Eds. D. S. Whitley and L. L .Loendorf, Institute of Archaeology, UCLA, Monograph 36, 9-12 (1994).