Forms the basis of archaeomagnetic dating
For the first time archaeomagnetic dating of the red pictorial layer was carried out at a Maya archaeological site, providing a direct date to the pigmented lime plasters.The method is based on the findings of Chiari and Lanza  who reported that the direction of the magnetic field persisted in the hematite of the red pigments of the pictorial layer in the Sistine Chapel.The pictorial layer of Structure 2 was the earliest (AD 274–316 and the stuccoes and plasters of the other two buildings were dated to the Middle Classic (AD 422–531), but we obtained different archaeomagnetic dates for the red pigment layers found in the buildings of the Pequeña Acrópolis and thus we were able to determine their chronological order of construction.The raw materials and proportions were carefully chosen to fulfil the mechanical necessities of the architectonic function: different proportions were found in plasters of floors, in the external walls, and inside the buildings; differences between earlier and later plasters were also detected.The analysis of lime mortars in the Maya area is difficult because the minerals (including composition, size, and textures) of aggregates and the binder (referred to in this paper as matrix) are the same or similar, with calcite being their main component, mainly in a micritic form.
Certain antecedents exist for radiocarbon dating the neoformed carbonates within the plaster matrix.
Although archaeometric studies of Maya lime mortars have been conducted since 1950 [1,2,3,4,5,6,7,8,9], information is scarce regarding production techniques and dating of lime mortars in the region of southern Quintana Roo.
There are some key publications [10,11,12,13,14,15,16] establishing the ways in which the Maya created their plasters, mortars, and stuccoes in a broad way.
We use mainly thin sections for the study and other types of analysis to reinforce the results.
Thus, combining the data on composition and structure of the plasters with their instrumental dating and archaeological characteristics, we intended to answer the following questions: Special attention was paid to the controversial issue of interpretation of the organic compounds in the plasters: our purpose was to identify them and to understand whether they were introduced intentionally as part of technological manipulations or appeared accidentally due to natural processes.