Prehispanic (Guanches) mummies and natrium salts in burial caves of Las Cañadas del Teide (Tenerife).

The prehispanic population of Tenerife (Guanches) buried their dead in caves. Many corpses are totally or partially mummified. Embalming procedures are largely unknown, besides some information recorded by chroniclers and the general idea that environmental conditions in some areas may favour natural mummification. Detailed observation of burial caves containing mummified corpses revealed the presence of a white mineral in form of crusts or powder that was not present in the vast majority of non-burial caves, especially in basaltic and trachybasaltic lava flows. We analysed these crusts and they consist of natrium carbonate salts. Therefore, we conducted a search visiting 30 caves, 3 of them harbouring mummified corpses, and made analyses if there were natrium salts in these caves and their amount. One burial cave was located in trachyphonolitic lava flow, and two further caves in trachybasaltic and basaltic lava flows. There was a significant association between presence of natrium salts and use of the cave as a burial site (χ2 = 9.37; p = 0.0259). The semiquantitatively assessed amount of natrium salts was also by far higher in burial caves than in non-burial ones (Z = 2.58, p = 0.01). There are no reports that support the use of natrium salts in the embalming process among the Guanches, but we found a clear-cut relationship between the presence and/or amount of natrium salts in caves and their use as burial sites by the prehispanic population buried in the central highlands, suggesting an intentional use of caves containing this mineral as burial caves, based perhaps on the observation of the ability of natrium salts to preserve corpses.