In 2012 we started a program of chemical analysis on organic extracts of 14 samples of fills, adobes, floors and renders, dated AD 200–400, obtained during the excavations of monumental earthen buildings at the archaeological site of La Joya, Veracruz, Mexico, located on the humid tropical coastal plain of the Gulf of Mexico. The interest in identifying organic additives derives from the observation that the conservation conditions of buildings is better than expected, considering the mineral composition of construction materials in which smectite (montmorillonite), an expansive clay, dominates. This brought us to suspect the presence of certain compounds which served as consolidant and/or water-repellent. The organic compounds from the building samples are extracted in hexane and methanol, and analyzed by Thin Layer Chromatography [TLC], Fourier Transform Infrared Spectroscopy [FTIR], Nuclear Magnetic Resonance Spectroscopy [NMR] (1H and 13C) and Mass Spectrometry [MS] (Fast Atom Bombardment [FAB+]). The results of these analyses confirm the presence of the same organic compounds in all samples, especially more abundant in adobe samples. The compounds identified up to now are hydrocarbons, a triglyceride and a sugar. At the same time, the mucilage of plants used in the vernacular construction in humid tropical environments in Central America is analyzed using a similar process in order to compare it with the organic substances of the original materials. The importance of identifying additives in pre-Columbian earthen buildings resides not only in understanding what made a tradition of earth construction possible in humid tropical environments, which contributes to the history of technology, but also in the possible use of such an additive in the conservation of archaeological remains, as well as in modern construction
organic additives archaeology Veracruz México Classic Period adobe Nuclear
Diğer ID | JA56NN98UE |
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Bölüm | Makaleler |
Yazarlar | |
Yayımlanma Tarihi | 23 Temmuz 2016 |
Yayımlandığı Sayı | Yıl 2013 Cilt: 3 Sayı: 1 |