Researchers use LiDAR data to study the subsistence of the Olmecs

Researchers use LiDAR data to study the subsistence of the Olmecs

A multidisciplinary team has used Digital Terrain Models generated from LiDAR data to evaluate the potential of available resources in the areas around the Olmec site of San Lorenzo, which is located in the south of the state of Veracruz, Mexico.

The Olmec culture settled in the south of the state of Veracruz and in the west of the state of Tabasco, and is recognized for its impressive monumental sculptures, among which those known as “colossal heads”, Which are large volcanic stone monoliths in which the faces of their rulers were possibly portrayed.

The settlement of San Lorenzo has been named as "the first Olmec capital”, Since it was one of the first sites to have monumental sculptures and to concentrate a large number of the population. It is estimated that between the years 1200 to 1100 BC San Lorenzo had a population of 11,800 inhabitants.

Questions about the Olmec culture

One of the main questions archaeologists had about the Olmec culture was about their livelihood, the initial approaches assumed that the Olmecs must have depended on corn as their main source of food, in the same way that later societies did. However, multiple studies have determined that corn was not very relevant in the diet of the inhabitants of Mesoamerica in dates before 1000 BC.

That is why it has been proposed that the early olmecs, as well as other contemporary Mesoamerican societies, they should depend on hunting, fishing and gathering. However, this raised the question of how San Lorenzo could have such a large population based on this type of economy.

The terrain study

Researchers from the National Autonomous University of Mexico and the University of Heidelberg analyzed Digital Terrain Models derived from LiDAR data of the National Institute of Statistics and Geography (INEGI) of Mexico, to study the northern plain of San Lorenzo.

Using data from archaeological excavations and algorithms, they were able to generate models that allow evaluate flood patterns and the evolution of ground depth through time.

The studies focused on the northern plain because in this area are the increased number of low-lying mounds, known as "islets", Which were possibly used as temporary base camps, where the hunter-fishermen of San Lorenzo processed the resources they captured.

Similarly, geomorphological and paleobotanical investigations they suggested that the northern plain must have been a wetland area in ancient times rich in aquatic flora and fauna.

The results of this research concluded that the northern plain of the site was deeper in ancient times, where a permanent wetland of great extension could be formed, which could have been a source of abundant aquatic resources, such as fish, crustaceans, reptiles and aquatic birds, which could be the basis of the subsistence of the inhabitants of San Lorenzo.

LiDAR, acronym from English Light Detection and Ranging, is a technology that uses a pulse laser beam to determine the distance between the laser emitter and an object or surface, which allows to generate high definition topographic maps.

This technology has been used by archaeologists mainly to detect archaeological sites in difficult-to-access areas, however this study presents an alternative and novel way in which LiDAR data can be used to study archaeological sites and the environment in the that were developed.

Bibliography:

Ramírez-Núñez, Carolina, Ann Cyphers, Jean-François Parrot & Bernhard Höfle. "Multidirectional Interpolation of Lidar Data from Southern Veracruz, Mexico: Implications for Early Olmec Subsistence”. In Ancient Mesoamerica, Cambridge University Press. pp. 1–14. http://doi.org/10.1017/S0956536118000263.


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