Mineral beads in an early domestic space of Northwest Argentina: Complementary non-invasive analytical techniques for findings from the Soria 2 site in the Yocavil Valley, Catamarca, Argentina

The work contributes to the body of knowledge on beads crafted from semi-precious stones that circulated in Northwest Argentina and Northern Chile for thousands of years. We present a compositional characterization of the only two beads, found at the Soria 2 site (Mesada de Andalhuala-Banda, Yocavil Valley, Catamarca, Argentina). The results were obtained through the integration of four complementary and minimally invasive analytical techniques: EDS, pXRF, XRD and nanoindentation, the latter being applied for the first time to this type of object in Northwest Argentina.

The results are temporally and spatially contextualized, as both beads were recovered during systematic excavations. They come from documented contexts within a residential structure dating to the early first millennium AD, the oldest known so far for the Yocavil Valley, although they belong to different social times: one represents the context when the space functioned as a household dwelling, while the other is associated with a later period, during which the abandoned house was transformed into a burial site for young children.

The complementary and critical combination of these four analytical techniques, approached from an interdisciplinary perspective, yielded novel information about the green-toned minerals selected to craft the beads. It was established that one bead is primarily composed of turquoise, while the other consists of chromium-rich muscovite. The possible sources of these raw materials are presented and discussed based on currently available data, aiming to achieve a deeper understanding of the ancient interaction networks through which these objects circulated during the first millennium AD.