Stable lead isotope ratios were determined on sixty-four samples taken from sixty of the Buddhist bronze images which were examined and chemically analyzed by Jett and Douglas [preceding paper]. The data were grouped using multivariate techniques and were compared with an accumulated data base of lead isotope measurements on more than 700 ancient Chinese artifacts and more than 200 Chinese and Korean ores. One group of ten images which were all datable to a period of less than one century, Eastern Wei through Sui dynasties, form a nearly unique isotopic group which coincides only with an unusual group of Lengshuichong bronze drums. A second large group of thirty-two isotopically matching images contains almost all, fifteen out of sixteen, of the images attributed to the Northern Wei dynasty. The remaining members of this group are of later date, extending into the Tang dynasty, or are animal figures attributed more generally to the Six Dynasties. This group partially overlaps somewhat the isotope fields of some Western and Eastern Han mirrors and some of the Sackler ritual bronze vessels of the Shang and Zhou dynasties, but appears to have been derived from a different ore source from them. The remaining specimens break up into some very tentatively defined small groups of two to four specimens each and a small residue of four unique, unmatched specimens.

Archaeologists, art historians and art conservators are almost constantly concerned with the questions of where, when and by whom the objects within their care were made. Knowledge of the conditions under which the objects were found may not answer these questions, as the objects may have traveled extensively or have existed for some time before they arrived at sites where they were discovered. Stylistic considerations often can provide answers, but not infallibly, as styles were sometimes copied at locations and at times quite different from those for which they were most characteristic. Compositional analysis can often help provide answers to these questions because traditions in the use of particular materials have often persisted in and accordingly have been characteristic of particular regions, periods and even of particular workshops. For example, the deliberate alloying of copper with tin, arsenic, antimony, lead and/or zinc has varied greatly from region to region and from time to time.