Geochemical characterisation of Otumba obsidian sub-sources (Central Mexico) by inductively coupled plasma mass spectrometry and density-based spatial clustering of applications with noise statistical analysis

Several obsidian sources that were significant to the lithic industry all over Mesoamerica are contained in the Central Mexico highlands. Many archaeological investigations have suggested that the economical and political expansion of important Mesoamerican cultures was related to the control of obsidian sources and its commercial routes. One of these sources was Otumba, located west of the Teotihuacan Valley. This region has several sub-sources, some of which have been studied in more detail than others. The most studied subsource is the one located on Soltepec Hill, but other related sub-sources within Otumba region that have not been studied include the Ixtete, Pacheco, Malpais and Tepayo domes. We have analysed samples from these four sub-sources with inductively coupled plasma mass spectrometry (ICP-MS) method to determine their chemical similarities and differences and classify them. The individual correlation of different archaeological artifacts with each sub-source could tell us about exploitation preferences of the diverse cultures controlling the source or even sequence in time of its utilisation.