Cave paintings of the Tierradentro tombs in Colombia

Experts from the National Archaeomagnetic Service (SAN) of the UNAM analyzed the red painting of a shaft tomb or hypogeum in Colombia and found that the site could be located between 1070 and 1150 A.D., a first approximation in the dating of these places, since these paintings, in these contexts, are not common in that country or elsewhere in the world, hence the importance of advancing in their study.

Avto Goguitcghaichvili, head of the SAN and researcher at the Institute of Geophysics of the UNAM, and Fernando Montejo, from the Colombian Institute of Anthropology and History, headed the work and explained that although the reported dates were controversial, they coincide with another similar burial dated with the Carbon 14 technique; and previous data that said that the hypogeum dated before Christ was rejected.

"We have concluded that the tentative date we report, under existing dating constraints, in this case, is very different from others previously reported. The interval is between 1070 and 1150 AD, thus discarding earlier dates, but it is contemporary with a similar burial in another place in the region called Rancho Grande, which gives a certain certainty to this dating that we are promoting", commented Goguitcghaichvili.

In turn, Montejo detailed that the hypogeum or shaft tombs (chamber and shaft tombs) are representative of Colombia in the Andean zone, in particular of the chieftainship season in the continent. As in Mexico, this type of structure is a particular type of funerary architecture where the deceased of the pre-Hispanic societies were deposited in the company of offerings, among which are splendid sculptures and ceramic vessels.

The sites had been investigated for some time, but the dating of the Alto de Segovia site was uncertain because the pieces previously analyzed were contaminated by materials from the volcanic tuff.

"This collaboration that we have just started with the UNAM experts has allowed us to have a first approximation, which is very interesting and coincides with the ceramic typologies that have been obtained in the region," he emphasized.

For the work with the SAN, he added, the main object of analysis was the rupestrian painting of the place, because until now it had not been tried to date it directly and due to the type of complex measurements that the university Service carries out, these turned out to be encouraging.

Goguitchaichvili explained that for the Service it is important to work with the sites considered World Heritage and those in charge of their care in each one of the nations, which reason why for five years it initiated the collaboration with experts to support the studies from Mesoamerica to South America. In this sense, the fruitful collaboration with the Colombian Institute of Anthropology and History is noteworthy.

One of the oldest ceramics in the American continent is in Colombia and from there arises the interest of making a regional curve of variation of the geomagnetic field, since it is not possible to use one of Mesoamerica or Europe because the terrestrial magnetic field is quite 'localist' or 'regionalist' and changes from one place to another of our planet.

Despite the enormous importance of this place, there has not been a consensus in terms of when they were painted or when their maximum splendor was, since the radiometric ages, including Carbon 14, give different results; some said that it was 4,000 years before Christ, which is undoubtedly an error due to contamination, he pointed out.

Usually, he commented, we work with archaeological objects burned at high temperatures, where the magnetization is analyzed thermoremanently. However, there is the possibility of working with mural paintings, which are artistic elements widely distributed throughout the world, but rarely dated directly.

To check the so-called pictorial remanent magnetization in these, the SAN researchers looked for iron oxides such as hematite, especially contained in the red paint.

Goguitcghaichvili emphasized that the collaboration will continue now with the ceramics associated with the site, but this would no longer be direct dating but of the archaeological context, so in that case, they will try to connect the results with the hypogeum.

Montejo added that they are interested in continuing with the cooperation because the gaps at the chronological level persist in several contexts of the country and they will continue reviewing the hypogeums of other emblematic parts in Colombia.

"This site of Tierra Adentro is included in the list of World Heritage Sites, and there are others that fall into this category, located in the Colombian Amazon, and we would like to have the collaboration of the SAN. There are several questions we still have in the country in chronological terms... there are still many questions about occupation sequences and important periods of pre-Hispanic archeology in the country (Colombia) that deserve the application of these techniques," he concluded.