LEAD ISOTOPES AS CHRONOLOGICAL MARKERS FOR COLONIAL-PERIOD CEREMONIAL DRINKING VESSELS IN THE ANDES

Ritual drinking vessels called qeros have been produced and used in Andes for millennia. Prior to the arrival of Spanish in 1532, these objects were manufactured from a variety of materials, including gold, silver, ceramic, stone and wood. In the colonial period, Andean artists continued to produce wooden qeros, many of which were decorated using a polychrome inlay technique. Almost all extant polychromed wooden qeros attributed to the colonial period derive from museum and private collections and lack provenience and precise means of dating. Thus, current understanding of these objects’ chronology has largely relied on stylistic and iconographic analyses. However, it is also possible to investigate the chronology and production of the qeros by characterizing the materials used in their manufacture. For example, by the late 1500s or early 1600s, native artists began to use lead white pigment (lead hydroxycarbonate or lead carbonate, introduced to the Andes by the Spanish) in the decoration of these vessels. Here, we demonstrate that the isotopic composition of lead white pigment may function as a chronological marker for colonial period qeros. We analyzed the Pb isotopic composition of lead white pigments taken from 21 qeros representing various stages of a stylistic chronology derived from Cummins (2002): early colonial (~1600-1650), middle colonial (~1650-1750), and late colonial (~1750-1800). We identify three distinct Pb isotopic fingerprints among these objects. We interpret two of these fingerprints to indicate an Iberian origin for Pb, and these correspond to stylistically early colonial qeros. We interpret the third fingerprint, associated mainly with stylistically middle to late period qeros, to indicate the pigment was manufactured from Andean Pb. Given the reproducibility of Pb isotope ratios among qeros decorated with Andean-attributed Pb, it is possible that these qeros were inlayed with lead white pigment synthesized from a single source (or single batch) of Pb metal. Overall, the results suggest that Andean artists initially used lead white pigment imported from Spain (or manufactured from Spanish ores) during the early colonial period. In contrast, later period qeros were decorated with lead white pigment that was likely synthesized from local ore sources.